福州网站制作外包,全能网站建设完全自学手册,网站设计 英文,咸宁网站开发Spring MVC Java 是第一大编程语言和开发平台。它有助于企业降低成本、缩短开发周期、推动创新以及改善应用服务。如今全球有数百万开发人员运行着超过 51 亿个 Java 虚拟机#xff0c;Java 仍是企业和开发人员的首选开发平台。 课程内容的介绍 1. Spring MVC 入门案例 2. 基…Spring MVC Java 是第一大编程语言和开发平台。它有助于企业降低成本、缩短开发周期、推动创新以及改善应用服务。如今全球有数百万开发人员运行着超过 51 亿个 Java 虚拟机Java 仍是企业和开发人员的首选开发平台。 课程内容的介绍 1. Spring MVC 入门案例 2. 基于注解的使用方式 3. 处理及响应请求 4. 文件上传下载操作 5. 静态资源处理 6. 服务端数据校验 7. 数据回写操作 8. 异常处理 9. JSON数据操作 10. Restful风格编程 11. 拦截器 12. Spring和Spring MVC整合操作 一、Spring MVC 入门案例 1. 什么是MVC 模型-视图-控制器MVC 是一个众所周知的以设计界面应用程序为基础的设计模式。它主要通过分离模型、视图及控制器在应用程序中的角色将业务逻辑从界面中解耦。通常模型负责封装应用程序数据在视图层展示。视图仅仅只是展示这些数据不包含任何业务逻辑。控制器负责接收来自用户的请求并调用后台服务manager或者dao来处理业务逻辑。处理后后台业务层可能会返回了一些数据在视图层展示。控制器收集这些数据及准备模型在视图层展示。MVC模式的核心思想是将业务逻辑从界面中分离出来允许它们单独改变而不会相互影响。 2. Spring MVC Spring Web MVC是一种基于Java的实现了Web MVC设计模式的请求驱动类型的轻量级Web框架。 使用了MVC架构模式的思想将Web层进行职责解耦。 基于请求驱动指的就是使用请求-响应模型。 框架的目的就是帮助我们简化开发。 Spring Web MVC也是要简化我们日常Web开发的。 SpringMVC的优点 性能比Struts2好。 简单、便捷易学。 和Spring无缝衔接【IoCAOP】。 使用约定优于配置。 支持Restful。 异常处理国际化数据验证类型转换等。 使用的人多使用的公司多。 3.第一个Spring MVC 案例 3.1 创建一个Web项目 创建一个基于Maven的Web项目添加相关的项目结构。 3.2 添加对应的依赖 dependencygroupIdorg.springframework/groupIdartifactIdspring-webmvc/artifactIdversion4.3.2.RELEASE/version
/dependency
dependencygroupIdjavax.servlet/groupIdartifactIdservlet-api/artifactIdversion2.5/versionscopeprovided/scope
/dependency Maven的依赖管理具有传递性。 3.3 添加一个Spring MVC的配置文件 添加一个Spring MVC的配置文件该配置文件的内容和我们前面介绍的Spring的配置文件的内容是一致的。 ?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd/beans 然后在配置文件中向Spring IoC容器中注入两个实例。 ?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd!-- 注入一个处理器映射器 --bean
classorg.springframework.web.servlet.handler.BeanNameUrlHandlerMapping /!-- 注入一个处理器适配器 --bean
classorg.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter //beans 3.4 配置前端控制器 Spring MVC是一个控制层框架那么需要处理所有的请求那么我们需要在web.xml文件中配置对应的拦截。 !DOCTYPE web-app PUBLIC-//Sun Microsystems, Inc.//DTD Web Application 2.3//ENhttp://java.sun.com/dtd/web-app_2_3.dtd web-appdisplay-nameArchetype Created Web Application/display-name!--配置一个Spring MVC 的前端控制器目的是所有的客户端的请求都会被 DispatcherServlet 处理--servletservlet-namespringmvc/servlet-nameservlet-classorg.springframework.web.servlet.DispatcherServlet/servlet-class!-- 关联自定义的Spring MVC的配置文件 --init-paramparam-namecontextConfigLocation/param-nameparam-valueclasspath:spring-mvc.xml/param-value/init-param/servletservlet-mappingservlet-namespringmvc/servlet-nameurl-pattern//url-pattern/servlet-mapping
/web-app 3.5 创建自定义的控制器 package com.bobo.controller;import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;public class UserController implements Controller {/*** 具体处理请求的方法* param httpServletRequest* param httpServletResponse* return* throws Exception*/Overridepublic ModelAndView handleRequest(HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse) throws Exception {System.out.println(请求进来了...);ModelAndView mm new ModelAndView();mm.setViewName(/index.jsp);return mm;}
}3.6 自定义控制器的注入 ?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd!-- 注入一个处理器映射器 --bean
classorg.springframework.web.servlet.handler.BeanNameUrlHandlerMapping /!-- 注入一个处理器适配器 --bean
classorg.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter /!-- 将自定义的控制器注入到IoC容器中 name/user 用户访问的请求地址 --bean classcom.bobo.controller.UserController name/user //beans 3.7 Tomcat插件 通过Tomcat插件来运行项目 plugins!-- tomcat插件 --plugingroupIdorg.apache.tomcat.maven/groupIdartifactIdtomcat7-maven-plugin/artifactIdversion2.2/versionconfiguration!-- 端口号 --port8082/port!-- /表示访问路径 省略项目名 --path//path!-- 设置编码方式 --uriEncodingutf-8/uriEncoding/configuration/plugin
/plugins 3.8 测试 启动成功 http://localhost:8082/user 访问成功 4. 基于注解的实现 通过上一个普通实现的方式大家会发现其实现步骤比较繁琐而且自定义的Controller也只有一个默认的方法被调用不是很方便。我们在开发中常用的是基于注解的方式实现的接下来就实现。 4.1 修改Spring MVC 的配置文件 ?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:contexthttp://www.springframework.org/schema/contextxmlns:mvchttp://www.springframework.org/schema/mvcxsi:schemaLocationhttp://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc.xsd
!-- 添加对应的扫描路径 --context:component-scan base-packagecom.bobo.controller/!-- 开启Spring MVC 注解的使用方式 --mvc:annotation-driven /
/beans 4.2 创建控制器 package com.bobo.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;import javax.jws.WebParam;Controller // 将当前类的对象交给容器管理
RequestMapping(/user) // 配置的而是请求的路径
public class UserController {/*** 查询方法* 请求地址* http://localhost:8082/user/query* return*/RequestMapping(/query)public ModelAndView query(){System.out.println(query);ModelAndView mm new ModelAndView();mm.setViewName(/index.jsp);return mm;}/*** 添加方法* 请求地址* http://localhost:8082/user/addUser* return*/RequestMapping(/addUser)public ModelAndView addUser(){System.out.println(add User ...);ModelAndView mm new ModelAndView();mm.setViewName(/index.jsp);return mm;}
} 4.3测试 5.Spring MVC 的工作原理 5.1 Spring MVC 原理图 Spring MVC 默认的配置信息 # Default implementation classes for DispatcherServlets strategy interfaces.
# Used as fallback when no matching beans are found in the DispatcherServletcontext.
# Not meant to be customized by application developers.org.springframework.web.servlet.LocaleResolverorg.springframework.web.servlet.i18n.AcceptHeaderLocaleResolverorg.springframework.web.servlet.ThemeResolverorg.springframework.web.servlet.theme.FixedThemeResolverorg.springframework.web.servlet.HandlerMappingorg.springframework.web.servlet.handler.BeanNameUrlHandlerMapping,\org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMappingorg.springframework.web.servlet.HandlerAdapterorg.springframework.web.servlet.mvc.HttpRequestHandlerAdapter,\org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter,\org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapterorg.springframework.web.servlet.HandlerExceptionResolverorg.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerExceptionResolver,\org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver,\org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolverorg.springframework.web.servlet.RequestToViewNameTranslatororg.springframework.web.servlet.view.DefaultRequestToViewNameTranslatororg.springframework.web.servlet.ViewResolverorg.springframework.web.servlet.view.InternalResourceViewResolverorg.springframework.web.servlet.FlashMapManagerorg.springframework.web.servlet.support.SessionFlashMapManager 5.2 工作原理文字说明 用户向服务器发送请求请求被Spring 前端控制Servelt DispatcherServlet捕获 DispatcherServlet对请求URL进行解析得到请求资源标识符URI。然后根据该URI调用HandlerMapping获得该Handler配置的所有相关的对象包括Handler对象以及Handler对象对应的拦截器最后以HandlerExecutionChain对象的形式返回 DispatcherServlet 根据获得的Handler选择一个合适的HandlerAdapter。附注如果成功获得HandlerAdapter后此时将开始执行拦截器的preHandler(…)方法 提取Request中的模型数据填充Handler入参开始执行HandlerController)。 在填充Handler的入参过程中根据你的配置Spring将帮你做一些额外的工作 HttpMessageConveter 将请求消息如Json、xml等数据转换成一个对象将对象转换为指定的响应信息。 数据转换对请求消息进行数据转换。如String转换成Integer、Double等。 数据根式化对请求消息进行数据格式化。 如将字符串转换成格式化数字或格式化日期等。 数据验证 验证数据的有效性长度、格式等验证结果存储到BindingResult或Error中。 Handler执行完成后向DispatcherServlet 返回一个ModelAndView对象 根据返回的ModelAndView选择一个适合的ViewResolver必须是已经注册到Spring容器中的ViewResolver)返回给DispatcherServlet ViewResolver 结合Model和View来渲染视图。 将渲染结果返回给客户端。 5.3 相关核心组件的说明 二、Spring MVC的核心操作 1.响应请求 1.1 ModelAndView 前面案例中使用的就是ModelAndView方式。 /*** 查询方法* 请求地址* http://localhost:8082/user/query* return*/RequestMapping(/query)public ModelAndView query(){System.out.println(query);ModelAndView mm new ModelAndView();mm.setViewName(/index.jsp);return mm;} 1.2 返回void 接收请求的方法如果没有要响应的资源这时我们可以将方法的返回结果设置为 void。 RequestMapping(/update)
public void updateUser(){System.out.println(update .... );
} 客户端发送了一个请求服务器获取到请求后没有给客户端响应那么课后会有错误提示如果确实是服务器没有要响应的内容那么我们需要添加一个 ResponseBody 注解表示请求到此为止。 /*** 返回结果信息为空* void ResponseBody*/RequestMapping(/update)ResponseBodypublic void updateUser(){System.out.println(update .... );} 1.3 返回一个字符串 为了简化响应操作我们可以直接返回一个要调整的页面对应的字符串即可。 *** 要跳转到哪个页面我们直接返回该页面对应的字符串即可** return*/RequestMapping(/deleteUser)public String deleteUser(){System.out.println(delete .....);// /index.jsp中的 / 表示的是绝对路径return redirect:/index.jsp;} 视图解析器在解析我们要返回的页面的时候我们可以给视图解析器配置对应的前后缀。来简化我们的响应。 ?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:contexthttp://www.springframework.org/schema/contextxmlns:mvchttp://www.springframework.org/schema/mvcxsi:schemaLocationhttp://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc.xsd
!-- 添加对应的扫描路径 --context:component-scan base-packagecom.bobo.controller/!-- 开启Spring MVC 注解的使用方式 --mvc:annotation-driven /!-- 配置视图解析器 --bean
classorg.springframework.web.servlet.view.InternalResourceViewResolver !-- 配置视图解析器的前后缀--property nameprefix value/ /property namesuffix value.jsp //bean
/beans 响应页面的时候就可以简写了。 /*** 要跳转到哪个页面我们直接返回该页面对应的字符串即可** return*/RequestMapping(/deleteUser1)public String deleteUser1(){System.out.println(delete1 .....);// /index.jsp中的 / 表示的是绝对路径return index;} 我们发现返回字符串的方式默认的跳转方式是请求转发如果我们要实现重定向只需要在响应的字符串前面添加 redirect: 即可。 RequestMapping(/deleteUser)
public String deleteUser(){System.out.println(delete .....);// /index.jsp中的 / 表示的是绝对路径return redirect:/index.jsp;
} 1.4 通过Servlet处理响应 Spring MVC中的 DispatcherServlet本质上就是一个Servlet所以我们当然也可以在控制器中使用Servlet来处理响应请求只是这种方式比较繁琐一般不用。 RequestMapping(/queryAll)
public void queryAll(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {System.out.println(query All ... );request.getRequestDispatcher(/index.jsp).forward(request,response);//response.sendRedirect(/index.jsp);
} 2.接收请求数据 介绍用户发送请求中携带的各种参数。 2.1 简单数据类型 如果客户端传递的简单数据类型我们可以直接在形参中声明要接收的信息。但是要注意声明的类型我们建议搭建都使用对应的包装类因为传递过来的参数有可能为null。 /*** 接收的参数为简单数据类型* param userName* param age* return*/RequestMapping(/query1)public String query1(String userName, Integer age){System.out.println(query1 ..... userName age);return /index.jsp;} 前面的方式要求形参和传递的参数名称要一致如果不一致我们需要通过 RequestParam 注解来设置映射。 /*** 接收的参数为简单数据类型* param userName* param age* return*/RequestMapping(/query1)public String query1(RequestParam(value name,defaultValue lisi) String userName,RequestParam(value userAge,defaultValue 18) Integer age){System.out.println(query1 ..... userName age);return /index.jsp;} 客户端访问的地址http://localhost:8082/stu/query1?namezhangsanuserAge22。 如果没有传递参数http://localhost:8082/stu/query1 会使用设置的默认值覆盖。 2.2 简单对象 如果客户端传递的参数比较多我们可以将传递的数据封装到自定义的对象中。 package com.bobo.bean;import org.springframework.web.bind.annotation.RequestParam;import java.util.List;public class StudentBean {private Integer id;private String userName;private Integer age;private String address;private ListString favrites;public ListString getFavrites() {return favrites;}public void setFavrites(ListString favrites) {this.favrites favrites;}// 包装类private Book book;public Book getBook() {return book;}public void setBook(Book book) {this.book book;}public Integer getId() {return id;}public void setId(Integer id) {this.id id;}public String getUserName() {return userName;}public void setUserName(String userName) {this.userName userName;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age age;}public String getAddress() {return address;}public void setAddress(String address) {this.address address;}Overridepublic String toString() {return StudentBean{ id id , userName userName \ , age age , address address \ , book book };}
}接收请求 /*** 通过自定义对象来接收参数* param stu* return*/RequestMapping(/addStudent)public String addStudent(StudentBean stu){System.out.println(stu);return /index.jsp;} http://localhost:8082/stu/addStudent?id666userNameaaaage18addresschangsha。 Book package com.bobo.bean;public class Book {private Integer bookId;private String bookName;private String author;public Integer getBookId() {return bookId;}public void setBookId(Integer bookId) {this.bookId bookId;}public String getBookName() {return bookName;}public void setBookName(String bookName) {this.bookName bookName;}public String getAuthor() {return author;}public void setAuthor(String author) {this.author author;}Overridepublic String toString() {return Book{ bookId bookId , bookName bookName \ , author author \ };}
}http://localhost:8082/stu/addBook?bookId123bookNamehelloWorldauthorbobo。 2.3 包装对象 我们自定义的对象中的属性是另一个对象(自定义对象)那这种情况我们应该怎么传递及接收相关的数据。 请求http://localhost:8082/stu/addStudentid666userNameaaaage18addresschangshabook.bookId999book.bookNameJavabianchengrumenbook.authorbobo 2.4 数组和集合类型 当我们在客户端通过表单提交复选框的数据的时候我们可以通过数组的形式来接收。 %--Created by IntelliJ IDEA.User: dpbDate: 2021/1/29Time: 16:36To change this template use File | Settings | File Templates.
--%
% page contentTypetext/html;charsetUTF-8 languagejava %
html
headtitleTitle/title
/head
bodyh1学生管理/h1form action/stu/addStudentNew methodpost label学生姓名:/labelinput typetext nameuserNamebrlabel兴趣爱好:/labelinput typecheckbox namefavrites valuefooterball足球input typecheckbox namefavrites valuebasketball篮球brinput typesubmit value提交/form
/body
/html RequestMapping(/addStudentNew)
public String addStudentNew(String userName,String[] favrites){System.out.println(userName : Arrays.toString(favrites) );return /index.jsp;
} 页面效果 那如果我们不用数组而是使用List集合呢 RequestMapping(/addStudentList)
public String addStudentList(String userName, ListString favrites){System.out.println(userName : favrites );return /index.jsp;
} 报错 也就是告诉大家我们不能在形参中直接通过集合来接收参数 我们也可以通过自定义对来接收在对象中声明数组或者集合类型的变量来接收。 属性声明为List类型也可以。 2.5 Date类型 如果我们需要接收一个时间类型数据直接在形参中声明 Date 类型会抛出类型转换的异常。 自己实现转换器 package com.bobo.convert;import org.springframework.core.convert.converter.Converter;import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;/*** 自定义一个转换器* 实现 String到Date类型的转换*/
public class DateConvert implements ConverterString, Date {Overridepublic Date convert(String s) {SimpleDateFormat sdf new SimpleDateFormat(yyyy-MM-dd);Date date null;try {date sdf.parse(s);} catch (ParseException e) {e.printStackTrace();}return date;}
}配置自定义的转换器 ?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:contexthttp://www.springframework.org/schema/contextxmlns:mvchttp://www.springframework.org/schema/mvcxsi:schemaLocationhttp://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc.xsd
!-- 添加对应的扫描路径 --context:component-scan base-packagecom.bobo.controller/!-- 开启Spring MVC 注解的使用方式 --mvc:annotation-driven conversion-serviceconversionServiceFactoryBean/!-- 配置视图解析器 --bean classorg.springframework.web.servlet.view.InternalResourceViewResolver !-- 配置视图解析器的前后缀property nameprefix value/ /property namesuffix value.jsp /--/bean!-- 注册自定义的转换器 --bean classorg.springframework.format.support.FormattingConversionServiceFactoryBeanidconversionServiceFactoryBeanproperty nameconverterssetbean classcom.bobo.convert.DateConvert//set/property/bean
/beans 测试 http://localhost:8082/stu/addUser1?birth2021-01-29 接收请求碰到的参数相关的类型小结。 3.响应用户数据 Maven项目创建的web.xml的schema不完整我们修改如下。 !DOCTYPE web-app PUBLIC-//Sun Microsystems, Inc.//DTD Web Application 2.3//ENhttp://java.sun.com/dtd/web-app_2_3.dtd web-app version2.5xmlnshttp://java.sun.com/xml/ns/javaeexmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://java.sun.com/xml/ns/javaeehttp://java.sun.com/xml/ns/javaee/web-app_2_5.xsddisplay-nameArchetype Created Web Application/display-name!--配置一个Spring MVC 的前端控制器目的是所有的客户端的请求都会被 DispatcherServlet 处理--servletservlet-namespringmvc/servlet-nameservlet-classorg.springframework.web.servlet.DispatcherServlet/servlet-class!-- 关联自定义的Spring MVC的配置文件 --init-paramparam-namecontextConfigLocation/param-nameparam-valueclasspath:spring-mvc.xml/param-value/init-param/servletservlet-mappingservlet-namespringmvc/servlet-nameurl-pattern//url-pattern/servlet-mapping!-- 配置设置编码的过滤器 --filterfilter-nameencodingFilter/filter-namefilter-classorg.springframework.web.filter.CharacterEncodingFilter/filter-classinit-paramparam-nameencoding/param-nameparam-valueUTF-8/param-value/init-paraminit-paramparam-nameforceRequestEncoding/param-nameparam-valuetrue/param-value/init-paraminit-paramparam-nameforceResponseEncoding/param-nameparam-valuetrue/param-value/init-param/filterfilter-mappingfilter-nameencodingFilter/filter-nameurl-pattern/*/url-pattern/filter-mapping
/web-app3.1 通过ModelAndView方式 RequestMapping(/fun1)public ModelAndView fun1(){System.out.println(fun1...);ModelAndView mm new ModelAndView();mm.setViewName(/person1.jsp);// 绑定一个回传信息mm.addObject(msg,Hello World);return mm;} 在页面中通过EL表达获取。 %--Created by IntelliJ IDEA.User: dpbDate: 2021/1/29Time: 17:20To change this template use File | Settings | File Templates.
--%
% page contentTypetext/html;charsetUTF-8 languagejava %
html
headtitleTitle/title
/head
body
h1Person管理/h1labelmsg:/label ${ msg } br
/body
/html效果 3.2 Map集合 我们可以在形参中声明一个Map类型的变量然后将要传递的数据保存在该变量中注意我们自己不用去实例化该Map容器。 /*** 响应数据我们可以在形参中声明一个Map集合* 来保存要响应的数据* return*/RequestMapping(/fun2)public String fun2(MapString,Object map){map.put(msg,map类型数据);map.put(username,张三);System.out.println(fun2....);return /person2.jsp;} 页面获取 %--Created by IntelliJ IDEA.User: dpbDate: 2021/1/29Time: 17:20To change this template use File | Settings | File Templates.
--%
% page contentTypetext/html;charsetUTF-8 languagejava %
html
headtitleTitle/title
/head
body
h1Person管理/h1labelmsg:/label ${ requestScope.msg } brlabelmsg:/label ${ sessionScope.msg } brlabelmsg:/label ${ applicationScope.msg } brlabeluserName:/label ${ username } br
/body
/html3.3 Model对象 RequestMapping(/fun3)public String fun3(Model model){model.addAttribute(msg,msg--model);model.addAttribute(username,bobo);System.out.println(fun3....);return /person2.jsp;} 3.4 ModelMap对象 ModelMap可以看成是Model和Map的组合因为ModelMap提供了Model和Map的API。 RequestMapping(/fun4)public String fun4(ModelMap model){model.addAttribute(msg,msg--modelMap你好啊);model.addAttribute(username,bobo);System.out.println(fun4....);return /person2.jsp;} 注意以上几种方式传递的数据都是保存在request作用域中的。 验证 %--Created by IntelliJ IDEA.User: dpbDate: 2021/1/29Time: 17:20To change this template use File | Settings | File Templates.
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% page contentTypetext/html;charsetUTF-8 languagejava %
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headtitleTitle/title
/head
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h1Person管理/h1labelmsg:/label ${ requestScope.msg } brlabelmsg:/label ${ sessionScope.msg } brlabelmsg:/label ${ applicationScope.msg } brlabeluserName:/label ${ username } br
/body
/html如果我们需要将某个参数保存到session作用域中我们只需要在类的头部添加 SessionAttributes 注解即可。 效果 4.中文乱码问题 接收请求中的数据-- POST方式提交【在Request中设置对应的编码方式】 GET方式提交【在Web容器中设置 Tomcat】 响应请求中的数据-- Response设置对应的编码方式 GET方式提交设置编码 POST方式提交及响应Response的设置。 在CharacterEncodingFilter这个过滤器中提供的有设置Request和response对应编码的方法。 protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {String encoding this.getEncoding();if (encoding ! null) {if (this.isForceRequestEncoding() || request.getCharacterEncoding() null) {request.setCharacterEncoding(encoding);}if (this.isForceResponseEncoding()) {response.setCharacterEncoding(encoding);}}filterChain.doFilter(request, response);
} 在web.xml文件中配置编码过滤器的设置。 !DOCTYPE web-app PUBLIC-//Sun Microsystems, Inc.//DTD Web Application 2.3//ENhttp://java.sun.com/dtd/web-app_2_3.dtd web-app version2.5xmlnshttp://java.sun.com/xml/ns/javaeexmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://java.sun.com/xml/ns/javaeehttp://java.sun.com/xml/ns/javaee/web-app_2_5.xsddisplay-nameArchetype Created Web Application/display-name!--配置一个Spring MVC 的前端控制器目的是所有的客户端的请求都会被 DispatcherServlet 处理--servletservlet-namespringmvc/servlet-nameservlet-classorg.springframework.web.servlet.DispatcherServlet/servlet-class!-- 关联自定义的Spring MVC的配置文件 --init-paramparam-namecontextConfigLocation/param-nameparam-valueclasspath:spring-mvc.xml/param-value/init-param/servletservlet-mappingservlet-namespringmvc/servlet-nameurl-pattern//url-pattern/servlet-mapping!-- 配置设置编码的过滤器 --filterfilter-nameencodingFilter/filter-namefilter-classorg.springframework.web.filter.CharacterEncodingFilter/filter-classinit-paramparam-nameencoding/param-nameparam-valueUTF-8/param-value/init-paraminit-paramparam-nameforceRequestEncoding/param-nameparam-valuetrue/param-value/init-paraminit-paramparam-nameforceResponseEncoding/param-nameparam-valuetrue/param-value/init-param/filterfilter-mappingfilter-nameencodingFilter/filter-nameurl-pattern/*/url-pattern/filter-mapping
/web-app服务端获取的中文信息就没有乱码了。 三、常见应用 1.文件上传操作 1.1 添加fileUpload的依赖 !-- 添加fileUpload的依赖 --
dependencygroupIdcommons-fileupload/groupIdartifactIdcommons-fileupload/artifactIdversion1.3.1/version
/dependency 因为依赖的传递性会自动添加commons-io这个jar 1.2 创建表单 要实现文件上传操作那么表单的提交方式必须是 POST 方式同时enctype必须是multipart/form-data 二进制方式提交。 %--Created by IntelliJ IDEA.User: dpbDate: 2021/1/29Time: 20:03To change this template use File | Settings | File Templates.
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% page contentTypetext/html;charsetUTF-8 languagejava %
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headtitleTitle/title
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bodyh1文件上传/h1form action/user/fileUpload methodpost enctypemultipart/form-datalabel用户名:/labelinput typetext nameusernamebrlabel头像:/labelinput typefile nameheadFilebrinput typesubmit value上传/form
/body
/html1.3 修改配置文件 我们可以在Spring MVC的配置文件中设置上传的相关参数。设置上传文件的大小限制上传文件的类型等。 ?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:contexthttp://www.springframework.org/schema/contextxmlns:mvchttp://www.springframework.org/schema/mvcxsi:schemaLocationhttp://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc.xsd
!-- 添加对应的扫描路径 --context:component-scan base-packagecom.bobo.controller/!-- 开启Spring MVC 注解的使用方式 --mvc:annotation-driven /!-- 配置文件上传的解析器 --bean classorg.springframework.web.multipart.commons.CommonsMultipartResolveridmultipartResolver!--通过设值注入的方式设置上传的相关参数 --property namemaxUploadSize value5232880//bean!-- 防止资源文件被Spring MVC拦截。我们在Spring MVC设置资源的映射关系 --!-- 防止资源文件被spring MVC拦截mvc:resources mapping/img/** location/img/ cache-period31556926/mvc:resources mapping/js/** location/js/ cache-period31556926/mvc:resources mapping/css/** location/css/ cache-period31556926/--/beans 注意: CommonsMultipartResolver这个Bean的id必须为multipartResolver 原因CommonsMultipartResolver Bean是在DispatcherServlet中加载的而DispatcherServlet是通过名字来查找这个Bean的。而其他的则是按照类型查找。 1.4 控制器中处理文件 在控制器中我们要接收上传的文件我们只需要在形参中声明 MultipartFile类型即可。 package com.bobo.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;import java.io.File;
import java.io.IOException;Controller
RequestMapping(/user)
public class UserController {/*** 文件上传操作* return*/RequestMapping(/fileUpload)public String fileUpload(String username, MultipartFile headFile) throws IOException {System.out.println(username : headFile.getOriginalFilename() );headFile.transferTo(new File(d:/tools/,123.jpg));return /index.jsp;}
} 2.文件下载操作 文件下载的操作关键是在服务端的处理。 /*** 文件下载*/RequestMapping(/download)public void fileDownload(HttpServletRequest request, HttpServletResponse response) throws Exception {File file new File(d:/tools/,123.jpg);// 设置响应头信息response.setCharacterEncoding(utf-8);response.setContentType(multipart/form-data);response.setHeader(Content-Disposition, attachment;fileName file.getName());// 打开需要下载的文件InputStream in new FileInputStream(file);// 激活下载的操作ServletOutputStream outputStream response.getOutputStream();// 实现下载操作-- 本质就是一个文件的复制操作byte[] b new byte[1024*1024];int length 0;while((length in.read(b)) 0){outputStream.write(b,0,length);}// 关闭连接outputStream.close();in.close();} SpringMVC中提供的下载方式 /*** 使用SpringMVC中提供的下载方式* param request* return* throws Exception*/RequestMapping(/download2)public ResponseEntitybyte[] download2(HttpServletRequest request) throws Exception{File file new File(d:/tools/,123.jpg);byte[] body null;InputStream in new FileInputStream(file);body new byte[in.available()];in.read(body);HttpHeaders headers new HttpHeaders();headers.add(Content-Disposition,attachment;fileName file.getName());HttpStatus status HttpStatus.OK;ResponseEntitybyte[] entity new ResponseEntity(body,headers,status);return entity;}3.静态资源文件处理 其实我们在前面的课程里面都没有在Web项目中使用静态资源文件(html,css,js,图片等资源)。当我们添加了html页面后访问的时候发现404了。 原因是什么呢 我们自己配置的web.xml中的信息覆盖掉了Tomcat默认的配置。 找到原因了怎么解决了我们在自己的web.xml专门制定不用覆盖的请求类型。 !-- 防止资源文件被Spring MVC的前端控制器拦截 --servlet-mappingservlet-namedefault/servlet-nameurl-pattern*.html/url-pattern/servlet-mappingservlet-mappingservlet-namedefault/servlet-nameurl-pattern*.css/url-pattern/servlet-mappingservlet-mappingservlet-namedefault/servlet-nameurl-pattern*.js/url-pattern/servlet-mappingservlet-mappingservlet-namedefault/servlet-nameurl-pattern*.jpg/url-pattern/servlet-mappingservlet-mappingservlet-namedefault/servlet-nameurl-pattern*.png/url-pattern/servlet-mapping 重启在访问就可以了。 当然我们还可以在SpringMVC的配置文件中设置 资源的映射关系。 !-- 防止资源文件被Spring MVC拦截。我们在Spring MVC设置资源的映射关系 --
!-- 防止资源文件被spring MVC拦截 --
mvc:resources mapping/img/** location/img/ cache-period31556926/
mvc:resources mapping/js/** location/js/ cache-period31556926/
mvc:resources mapping/css/** location/css/ cache-period31556926/ 4.服务端数据校验 4.1 为什么需要服务端校验 最早的校验就是服务端校验。早期的网站用户输入一个邮箱地址校验邮箱地址需要将地址发送到服务端服务端进行校验校验成功后给前端一个响应。有了JavaScript校验工作可以放在前端去执行。那么为什么还需要服务端校验呢 因为前端传来的数据不可信。前端很容易获取都后端的数据接口如果有人绕过页面就会出现非法数据所以服务端也要数据校验总的来说 1. 前端校验要做目的是为了提高用户体验。 2. 后端校验也要做目的是为了数据安全。 4.2 普通校验 Springmvc本身没有校验功能它使用Hibernate的校验框架Hibernate的校验框架和orm没有关系。 引入hibernate相关的依赖 dependencygroupIdorg.hibernate/groupIdartifactIdhibernate-validator/artifactIdversion5.3.0.Alpha1/version
/dependency 将验证框架引入SpringMVC中 ?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:contexthttp://www.springframework.org/schema/contextxmlns:mvchttp://www.springframework.org/schema/mvcxsi:schemaLocationhttp://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc.xsd
!-- 添加对应的扫描路径 --context:component-scan base-packagecom.bobo.controller/!-- 开启Spring MVC 注解的使用方式 --mvc:annotation-driven validatorvalidatorFactoryBean/!-- 配置Hibernate-validator验证框架 --bean classorg.springframework.validation.beanvalidation.LocalValidatorFactoryBean idvalidatorFactoryBeanproperty nameproviderClass valueorg.hibernate.validator.HibernateValidator/property namevalidationMessageSource refbundleMessageSource//bean!-- 添加Hibernate验证框架的相关属性信息 --bean classorg.springframework.context.support.ReloadableResourceBundleMessageSource idbundleMessageSourceproperty namefileEncodings valueutf-8/property namecacheSeconds value120 //bean/beans bean对象中设置验证规则 Controller设置校验 package com.bobo.controller;import com.bobo.bean.UserBean;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.validation.ObjectError;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.RequestMapping;import java.util.List;Controller
RequestMapping(/user)
public class UserController {/**** param user Validated 修饰表示user会被校验* param br 校验的结果* return*/RequestMapping(/addUser)public String addUser(Validated UserBean user, BindingResult br, Model m) {// 对客户端提交的用户数据检验/*if(user ! null){if(user.getUserName().length() 3 ){}}*/// 获取校验结果ListObjectError allErrors br.getAllErrors();for (ObjectError allError : allErrors) {System.out.println(allError.getDefaultMessage());}m.addAttribute(errors,allErrors);return /index.jsp;}
} 测试提交的表单数据都为空的情况。 4.3 分组校验 为什么要使用分组校验 因为一个对象有多个属性而不同的controller校验的需求是不一样的必须c1只需要校验对象的账号是否为空就可以了而c2不光要校验账号为空还需要校验手机号必须不能为空这时分组校验就能解决这个问题了。实现步骤如下 定义分组 校验规则中使用分组 Controller中使用 package com.bobo.controller;import com.bobo.bean.UserBean;
import com.bobo.group.GroupInterface1;
import com.bobo.group.GroupInterface2;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.validation.ObjectError;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.RequestMapping;import java.util.List;Controller
RequestMapping(/user)
public class UserController {/**** param user Validated 修饰表示user会被校验* param br 校验的结果* return*/RequestMapping(/addUser)public String addUser(Validated(value GroupInterface2.class) UserBean user, BindingResult br, Model m) {// 对客户端提交的用户数据检验/*if(user ! null){if(user.getUserName().length() 3 ){}}*/// 获取校验结果ListObjectError allErrors br.getAllErrors();for (ObjectError allError : allErrors) {System.out.println(allError.getDefaultMessage());}m.addAttribute(errors,allErrors);return /index.jsp;}RequestMapping(/udpateUser)public String udpate(Validated(value GroupInterface1.class) UserBean user, BindingResult br, Model m){return /index.jsp;}}5.数据回写 5.1 普通实现方式 Controller
RequestMapping(/user)
public class UserController {RequestMapping(/doLogin)public String doLogin(String userName, String password, Model model){model.addAttribute(userName,userName);model.addAttribute(password,password);return forward:/login.jsp;}
} %--Created by IntelliJ IDEA.User: dpbDate: 2021/1/30Time: 14:14To change this template use File | Settings | File Templates.
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% page contentTypetext/html;charsetUTF-8 languagejava %
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headtitleTitle/title
/head
bodyh1登录页面/h1获取全局配置信息:${as} brform action/user/doLogin methodpostlabel用户名:/labelinput typetext nameuserName value${userName}brlabel密码:/labelinput typetext namepassword value${password}brinput typesubmit value提交/form
/body
/html5.2 通过Model方式实现 如果使用对象去接收客户端传递的参数那么对象默认会被自动放到Model中(Request作用域中)在前端页面可以直接使用对象的数据。这样开发效率会更高。 /*** 如果我们用对象去接收请求传递的参数。* 那么该对象默认会被保存到Model对象中* model.addAttribute(userBean,user)* param user* return*/RequestMapping(/addUser)public String addUser(UserBean user) {System.out.println(user);return /user.jsp;} 前端页面中的信息 %--Created by IntelliJ IDEA.User: dpbDate: 2021/1/29Time: 20:03To change this template use File | Settings | File Templates.
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% page contentTypetext/html;charsetUTF-8 languagejava %
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headtitleTitle/title
/head
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获取全局配置信息:${as} brform action/user/addUser methodpost label编号:/labelinput typetext nameid value${user.id}brlabel用户名:/labelinput typetext nameuserName value${user.userName}brinput typesubmit value添加/form
/body
/html效果 5.3 ModelAttribute注解的实现 修改参数回写变量名 在需要回传的对象前添加ModelAttribute注解可以设置对象在Model中的key值。实现更加灵活的操作。 配置全局变量名 /*** 配置全局的信息* 该类中的其他方法在处理请求后都会绑定本方法的返回信息* return*/ModelAttribute(as)public ListString getAllAddress(){return Arrays.asList(深圳,长沙,北京);} 6.异常处理 如果我们对系统没有做统一的异常管理那么当系统抛出异常信息的时候会给客户很不好的体验。 全局异常处理器处理 package com.bobo.resolver;import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** 全局异常处理器*/
Component
public class MyExceptionResolver implements HandlerExceptionResolver {/*** 处理异常* param httpServletRequest* param httpServletResponse* param o* param e* return*/Overridepublic ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) {System.out.println(e.getMessage());ModelAndView mm new ModelAndView();mm.setViewName(/500.jsp);return mm;}
}不要忘了添加扫描路径 这时再抛出异常看到的就是我们自定义的错误页面了。 7.JSON数据操作 7.1 响应JSON数据 我们在本课程中使用的是Jackson. 添加依赖 dependencygroupIdcom.fasterxml.jackson.core/groupIdartifactIdjackson-core/artifactIdversion2.5.2/version
/dependency
dependencygroupIdcom.fasterxml.jackson.core/groupIdartifactIdjackson-databind/artifactIdversion2.5.2/version
/dependency 控制层中响应数据 Controller
RequestMapping(/person)
public class PersonController {RequestMapping(/getUser)ResponseBodypublic UserBean getUser(){UserBean user new UserBean();user.setId(666);user.setUserName(波波);user.setGender(男);user.setAddress(湖南长沙);return user;}
} RequestMapping(/getAllUser)ResponseBodypublic ListUserBean getAllUser(){UserBean user new UserBean();user.setId(666);user.setUserName(波波);user.setGender(男);user.setAddress(湖南长沙);UserBean user2 new UserBean();user2.setId(123);user2.setUserName(波波1);user2.setGender(男1);user2.setAddress(湖南长沙1);ListUserBean list new ArrayList();list.add(user);list.add(user2);return list;} 通过以上案例可知我们返回的任意的Java对象数据Jackson都会将其转换为JSON数据。 注意 对于Gson和Jackson这两个json处理依赖直接添加即可。 除此之外其他的JSON解析器如Fastjson都需要手动配置HttpMessageConverter. 实际上在SpringMVC中是由一个名叫HttpMessageConverter的类来提供对象到JSON字符串的转换的。而SpringMVC默认就提供了Gson和Jackson的HttpMessageConverter分别是org.springframework.http.converter.json.GsonHttpMessageConverter和MappingJackson2HttpMessageConverter。对于其他的JSON解析器只需要开发者手动配置一 下HttpMessageConverter即可。 本案例使用 Jackson处理 FastJSON的配置案例 mvc:annotation-driven validatorvalidatorFactoryBeanmvc:message-convertersbeanclasscom.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter/bean/mvc:message-converters/mvc:annotation-driven 7.2 接收JSON数据 注意JSON只能是在请求体中因此JSON只能放在POST获取PUT请求中。 /*** 客户端发送的是JSON格式的字符串* param user*/RequestMapping(/addUser2)ResponseBodypublic void addUser2(RequestBody UserBean user){System.out.println(user);} 通过JQuery的ajax发送json数据 %--Created by IntelliJ IDEA.User: dpbDate: 2021/1/30Time: 16:23To change this template use File | Settings | File Templates.
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headtitleTitle/titlescript srchttps://s3.pstatp.com/cdn/expire-1-M/jquery/3.3.1/jquery.min.js/script
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input typebutton value提交JSON数据 onclickfun1();
script typetext/javascriptfunction fun1(){$.ajax({type: POST,url: person/addUser2,contentType: application/json,//如果想以json格式把数据提交到后台的话这个必须有否则只会当做表单提交data: JSON.stringify({userName:bobo,password:12345}),//JSON.stringify()必须有,否则只会当做表单的格式提交dataType: json,//期待返回的数据类型success: function(data){alert(success:data);},error:function(data){alert(errordata);}});}
/script
/body
/html测试当我们点击提交按钮会把JSON数据发送给服务器Jackson会将我们的JSON字符串转换为UserBean对象。 8、Restful风格 RESTful是一种软件设计规范是客户端和服务端进行数据交互的一个规范。 早期使用JSP页面开发网页时数据交互基本都是通过表单提交然后通过内置对象传递。当HTML5兴起移动互联网兴起网站后端服务不仅要考虑PC端的网页也要考虑移动端数据的展示、小程序、HTML5页面等。如果需要多个终端Android、iOS、小程序、Pad、HTML5页面共用一个后端一般来说主流方案就是使用JSON进行传递。RESTful则规范了请求的URL注意RESTful只是一个规范不是一个技术。 在RESTful中 1. 一个URL操作一个资源。 2. 请求的URL中不能有动词。 3. 使用HTTP的请求方式来描述请求行为例如 在RESTful接口中所有的方法都是返回JSON没有返回页面的(ModelAndView)因此所有的方法上都需要添加ResponseBody注解。一个替代的简化方案是使用 RestController 代替Controller。RestController实际上是一个组合注解是Controller和ResponseBody的组合 Target({ElementType.TYPE})
Retention(RetentionPolicy.RUNTIME)
Documented
Controller
ResponseBody
public interface RestController {String value() default ;
} Restful风格是使用 控制器中的编码 package com.bobo.controller;import com.bobo.bean.UserBean;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;import java.util.ArrayList;
import java.util.List;/*** Restful风格编程介绍*/
/*ResponseBody
Controller*/
RestController
public class StudentController {/*** 查询用户的方法* 基于Restf风格的规范该请求只能接受GET方式提交的请求* return*///RequestMapping(/getAll)GetMapping(/stus/{id})//RequestMapping(value /stus,method RequestMethod.POST)public ListUserBean getAllUser(PathVariable Integer id){System.out.println(查询数据---id);ListUserBean list new ArrayList();list.add(new UserBean(1,root,123456));list.add(new UserBean(2,admin,123456));return list;}/*** 添加用户数据* 接受POST方式提交* param user* return*/PostMapping(/stus)public String addUser(RequestBody UserBean user){System.out.println(添加数据user);return 数据添加成功...;}DeleteMapping(/stus/{id})public String deleteUser(PathVariable Integer id){System.out.println(删除的编号: id);return 删除数据成功...;}PutMapping(/stus)public String updateUser(RequestBody UserBean user){System.out.println(更新数据: user);return 更新数据成功...;}
}POSTMan中的提交设置 9、拦截器 9.1 简介 SpringMVC中的拦截器对应了Web基础中的过滤器。 拦截器和过滤器的区别 9.2 使用 创建拦截器 package com.bobo.interceptor;import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** 自定义的拦截器*/
public class MyInterceptor implements HandlerInterceptor {/*** 自定义处理器处理请求之前执行的方法* param httpServletRequest* param httpServletResponse* param o* return* true 表示放过请求* false 表示拦截请求* throws Exception*/Overridepublic boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {System.out.println(preHandle .... );return true;}/*** 在目标方法执行完成后执行的方法* postHandle 在afterCompletion之前执行* 返回ModelAndView之前执行* 我们可以修改ModelAndView中的信息* param httpServletRequest* param httpServletResponse* param o* param modelAndView* throws Exception*/Overridepublic void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o,ModelAndView modelAndView) throws Exception {System.out.println(ModelAndView执行之前操作...);modelAndView.setViewName(/index.jsp);System.out.println(postHandle ....);}/*** 在目标方法执行完成后执行的方法* 返回ModelAndView之后执行* 改变不了ModelAndView中的信息* 只能做一些资源回收相关的工作* param httpServletRequest* param httpServletResponse* param o* param e* throws Exception*/Overridepublic void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {System.out.println(afterCompletion ... );}
}需要将自定义的拦截器添加到IoC容器中修改配置文件。 ?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:contexthttp://www.springframework.org/schema/contextxmlns:mvchttp://www.springframework.org/schema/mvcxsi:schemaLocationhttp://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc.xsd
!-- 添加对应的扫描路径 --context:component-scan base-packagecom.bobo.controller,com.bobo.resolver/!-- 开启Spring MVC 注解的使用方式 --mvc:annotation-driven /!-- 配置自定义的拦截器 --mvc:interceptorsmvc:interceptor!-- 拦截的映射地址 /** 表示拦截根目录及其子目录下的所有的请求 --mvc:mapping path/user/**/bean classcom.bobo.interceptor.MyInterceptor //mvc:interceptor/mvc:interceptors/beans 拦截器工作原理 四、Spring MVC 整合Spring框架 1.整合实现步骤 1.1 创建Web项目 补全相关的目录结构 1.2 添加相关的依赖 我们需要在pom文件中添加对应的依赖。 dependencygroupIdorg.springframework/groupIdartifactIdspring-webmvc/artifactIdversion4.3.4.RELEASE/version
/dependency
dependencygroupIdjavax.servlet/groupIdartifactIdservlet-api/artifactIdversion2.5/versionscopeprovided/scope
/dependency 1.3 添加Spring的配置文件 在Spring的配置文件中添加扫描路径。 ?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:contexthttp://www.springframework.org/schema/contextxsi:schemaLocationhttp://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsd
!-- 配置扫描路径 --context:component-scan base-packagecom.bobo.service.impl,com.bobo.dao.impluse-default-filterstrue!-- 排除掉Controller注解的使用 --context:exclude-filter typeannotation expressionorg.springframework.stereotype.Controller//context:component-scan/beans 1.4 添加Spring MVC的配置文件 在Spring MVC 的配置文件中添加扫描和开启注解的使用。 ?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:contexthttp://www.springframework.org/schema/contextxmlns:mvchttp://www.springframework.org/schema/mvcxsi:schemaLocationhttp://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc.xsd
!-- 配置扫描路径 --context:component-scan base-packagecom.bobo.controller use-default-filtersfalse context:include-filter typeannotation expressionorg.springframework.stereotype.Controller//context:component-scan!-- 开启注解 --mvc:annotation-driven /mvc:annotation-driven
/beans 1.5 添加Tomcat的插件 plugins!-- tomcat插件 --plugingroupIdorg.apache.tomcat.maven/groupIdartifactIdtomcat7-maven-plugin/artifactIdversion2.2/versionconfiguration!-- 端口号 --port8082/port!-- /表示访问路径 省略项目名 --path//path!-- 设置编码方式 --uriEncodingutf-8/uriEncoding/configuration/plugin/plugins 1.6 web.xml文件的配置 !DOCTYPE web-app PUBLIC-//Sun Microsystems, Inc.//DTD Web Application 2.3//ENhttp://java.sun.com/dtd/web-app_2_3.dtd web-app version2.5xmlnshttp://java.sun.com/xml/ns/javaeexmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://java.sun.com/xml/ns/javaeehttp://java.sun.com/xml/ns/javaee/web-app_2_5.xsddisplay-nameArchetype Created Web Application/display-name!-- 配置Spring --context-paramparam-namecontextConfigLocation/param-nameparam-valueclasspath:applicationContext.xml/param-value/context-paramlistenerlistener-classorg.springframework.web.context.ContextLoaderListener/listener-class/listener!-- 配置Servlet的前端控制器 --servletservlet-namespringmvc/servlet-nameservlet-classorg.springframework.web.servlet.DispatcherServlet/servlet-class!-- 关联自定义的Spring MVC的配置文件 --init-paramparam-namecontextConfigLocation/param-nameparam-valueclasspath:spring-mvc.xml/param-value/init-param/servletservlet-mappingservlet-namespringmvc/servlet-name!-- 支持Restful风格编程 --url-pattern//url-pattern/servlet-mapping!-- 配置字符编码的过滤器 --!-- 配置设置编码的过滤器 --filterfilter-nameencodingFilter/filter-namefilter-classorg.springframework.web.filter.CharacterEncodingFilter/filter-classinit-paramparam-nameencoding/param-nameparam-valueUTF-8/param-value/init-paraminit-paramparam-nameforceRequestEncoding/param-nameparam-valuetrue/param-value/init-paraminit-paramparam-nameforceResponseEncoding/param-nameparam-valuetrue/param-value/init-param/filterfilter-mappingfilter-nameencodingFilter/filter-nameurl-pattern/*/url-pattern/filter-mapping!-- default 防止静态资源拦截 --servlet-mappingservlet-namedefault/servlet-nameurl-pattern*.html/url-pattern/servlet-mappingservlet-mappingservlet-namedefault/servlet-nameurl-pattern*.css/url-pattern/servlet-mappingservlet-mappingservlet-namedefault/servlet-nameurl-pattern*.js/url-pattern/servlet-mappingservlet-mappingservlet-namedefault/servlet-nameurl-pattern*.jpg/url-pattern/servlet-mappingservlet-mappingservlet-namedefault/servlet-nameurl-pattern*.png/url-pattern/servlet-mapping
/web-app1.7创建对应的逻辑代码 创建JavaBean对象 package com.bobo.bean;public class UserBean {private Integer id;private String userName;public Integer getId() {return id;}public void setId(Integer id) {this.id id;}public String getUserName() {return userName;}public void setUserName(String userName) {this.userName userName;}Overridepublic String toString() {return UserBean{ id id , userName userName \ };}public UserBean(Integer id, String userName) {this.id id;this.userName userName;}public UserBean() {}
}创建Dao层 package com.bobo.dao;import com.bobo.bean.UserBean;public interface IUserDao {UserBean getUserBean();
}创建实现 package com.bobo.dao.impl;import com.bobo.bean.UserBean;
import com.bobo.dao.IUserDao;
import org.springframework.stereotype.Repository;Repository
public class UserDaoImpl implements IUserDao {Overridepublic UserBean getUserBean() {return new UserBean(666,bobo);}
}创建Service接口 package com.bobo.service;import com.bobo.bean.UserBean;public interface IUserService {UserBean getUserBean();
}创建对应的实现 package com.bobo.service.impl;import com.bobo.bean.UserBean;
import com.bobo.dao.IUserDao;
import com.bobo.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;Service
public class UserServiceImpl implements IUserService {Autowiredprivate IUserDao dao;Overridepublic UserBean getUserBean() {return dao.getUserBean();}
}创建Controller package com.bobo.controller;import com.bobo.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;RestController
public class UserController {Autowiredprivate IUserService service;GetMapping(/user/query)public String query(){return service.getUserBean().toString();}
}1.8 测试效果 能够获取到Dao中返回的信息那就说明访问到来Controller中的方法说明Spring MVC没有问题同时Controller可以获取Service对象Service可以获取Dao中的对象那说明Spring的IoC容器也是OK的 2.Spring IoC 源码浅析 分析的入口代码 package com.bobo.test;import com.bobo.bean.UserBean;
import com.bobo.service.IUserService;
import com.bobo.service.impl.UserServiceImpl;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class Test01 {Testpublic void fun1(){// 进入源码 Ctrl鼠标点击 进入ApplicationContext ac new ClassPathXmlApplicationContext(applicationContext.xml);System.out.println(ac.getBean(IUserService.class));}
}进入ClassPathXmlApplicationContext构造方法 public ClassPathXmlApplicationContext(String configLocation) throws BeansException {this(new String[]{configLocation}, true, (ApplicationContext)null);
} 再进入 public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh,ApplicationContext parent) throws BeansException {// 初始化父类super(parent);// 设置本地配置信息this.setConfigLocations(configLocations);// 完成Spring容器的初始化操作if (refresh) {this.refresh();}
} 看源码的时候如果要回退那么就 CtrlAlt 方向键 public void refresh() throws BeansException, IllegalStateException {synchronized(this.startupShutdownMonitor) {// 准备工作this.prepareRefresh();// 获取BeanFactory工厂对象并且完成 配置文件的而加重解析操作ConfigurableListableBeanFactory beanFactory this.obtainFreshBeanFactory();this.prepareBeanFactory(beanFactory);try {this.postProcessBeanFactory(beanFactory);this.invokeBeanFactoryPostProcessors(beanFactory);this.registerBeanPostProcessors(beanFactory);this.initMessageSource();this.initApplicationEventMulticaster();this.onRefresh();this.registerListeners();this.finishBeanFactoryInitialization(beanFactory);this.finishRefresh();} catch (BeansException var9) {if (this.logger.isWarnEnabled()) {this.logger.warn(Exception encountered during contextinitialization - cancelling refresh attempt: var9);}this.destroyBeans();this.cancelRefresh(var9);throw var9;} finally {this.resetCommonCaches();}}
} 重点查看obtainFreshBeanFactory方法。 protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {// 刷新BeanFactory对象this.refreshBeanFactory();// 获取BeanFactory对象 说明已经完成了 BeanFactory的创建和 配置文件的加载解析操作ConfigurableListableBeanFactory beanFactory this.getBeanFactory();if (this.logger.isDebugEnabled()) {this.logger.debug(Bean factory for this.getDisplayName() : beanFactory);}return beanFactory;
} 进入 protected final void refreshBeanFactory() throws BeansException {// 判断BeanFactory是否已经存在if (this.hasBeanFactory()) {// 存在 就销毁和关闭this.destroyBeans();this.closeBeanFactory();}try {// 创建BeanFactory对象DefaultListableBeanFactory beanFactory this.createBeanFactory();beanFactory.setSerializationId(this.getId());this.customizeBeanFactory(beanFactory);// 加载解析配置文件this.loadBeanDefinitions(beanFactory);synchronized(this.beanFactoryMonitor) {this.beanFactory beanFactory;}} catch (IOException var5) {throw new ApplicationContextException(I/O error parsing bean definition source for this.getDisplayName(), var5);}
} 创建BeanFactory对象的具体方法。 protected DefaultListableBeanFactory createBeanFactory() {return new DefaultListableBeanFactory(this.getInternalParentBeanFactory());
} protected void loadBeanDefinitions(DefaultListableBeanFactory beanFactory)
throws BeansException, IOException {XmlBeanDefinitionReader beanDefinitionReader new XmlBeanDefinitionReader(beanFactory);beanDefinitionReader.setEnvironment(this.getEnvironment());beanDefinitionReader.setResourceLoader(this);beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(this));this.initBeanDefinitionReader(beanDefinitionReader);// 核心代码 直接进入this.loadBeanDefinitions(beanDefinitionReader);
} protected void loadBeanDefinitions(XmlBeanDefinitionReader reader) throws BeansException, IOException {Resource[] configResources this.getConfigResources();if (configResources ! null) {reader.loadBeanDefinitions(configResources);}String[] configLocations this.getConfigLocations();if (configLocations ! null) {reader.loadBeanDefinitions(configLocations);}
} 进入loadBeanDefinitions public int loadBeanDefinitions(Resource... resources) throws BeanDefinitionStoreException {Assert.notNull(resources, Resource array must not be null);int counter 0;Resource[] var3 resources;int var4 resources.length;for(int var5 0; var5 var4; var5) {Resource resource var3[var5];counter this.loadBeanDefinitions((Resource)resource);}// 统计解析的配置文件的个数return counter;
} 进入loadBeanDefinitions方法中。 public int loadBeanDefinitions(Resource resource) throws BeanDefinitionStoreException {return this.loadBeanDefinitions(new EncodedResource(resource));
} public int loadBeanDefinitions(EncodedResource encodedResource) throws BeanDefinitionStoreException {Assert.notNull(encodedResource, EncodedResource must not be null);if (this.logger.isInfoEnabled()) {this.logger.info(Loading XML bean definitions from encodedResource.getResource());}SetEncodedResource currentResources (Set)this.resourcesCurrentlyBeingLoaded.get();if (currentResources null) {currentResources new HashSet(4);this.resourcesCurrentlyBeingLoaded.set(currentResources);}if (!((Set)currentResources).add(encodedResource)) {throw new BeanDefinitionStoreException(Detected cyclic loading of encodedResource - check your import definitions!);} else {int var5;try {// 获取配置文件对应的字节输入流InputStream inputStream encodedResource.getResource().getInputStream();try {InputSource inputSource new InputSource(inputStream);// 设置对应的编码方式if (encodedResource.getEncoding() ! null) {inputSource.setEncoding(encodedResource.getEncoding());}// 核心代码 执行解析操作var5 this.doLoadBeanDefinitions(inputSource, encodedResource.getResource());} finally {inputStream.close();}} catch (IOException var15) {throw new BeanDefinitionStoreException(IOException parsing XML document from encodedResource.getResource(), var15);} finally {((Set)currentResources).remove(encodedResource);if (((Set)currentResources).isEmpty()) {this.resourcesCurrentlyBeingLoaded.remove();}}return var5;}
}protected int doLoadBeanDefinitions(InputSource inputSource, Resource resource)throws BeanDefinitionStoreException {try {// 将xml中的内容加载到Document对象中Document doc this.doLoadDocument(inputSource, resource);// 完成配置文件的注册操作 将配置文件中的信息载入到BeanDefinition对象中return this.registerBeanDefinitions(doc, resource);} catch (BeanDefinitionStoreException var4) {throw var4;} catch (SAXParseException var5) {throw new XmlBeanDefinitionStoreException(resource.getDescription(),Line var5.getLineNumber() in XML document from resource isinvalid, var5);} catch (SAXException var6) {throw new XmlBeanDefinitionStoreException(resource.getDescription(),XML document from resource is invalid, var6);} catch (ParserConfigurationException var7) {throw new BeanDefinitionStoreException(resource.getDescription(),Parser configuration exception parsing XML from resource, var7);} catch (IOException var8) {throw new BeanDefinitionStoreException(resource.getDescription(),IOException parsing XML document from resource, var8);} catch (Throwable var9) {throw new BeanDefinitionStoreException(resource.getDescription(),Unexpected exception parsing XML document from resource, var9);}
} 关键方法registerBeanDefinitions public int registerBeanDefinitions(Document doc, Resource resource) throws BeanDefinitionStoreException {BeanDefinitionDocumentReader documentReader this.createBeanDefinitionDocumentReader();int countBefore this.getRegistry().getBeanDefinitionCount();// 具体注册的方法documentReader.registerBeanDefinitions(doc, this.createReaderContext(resource));return this.getRegistry().getBeanDefinitionCount() - countBefore;
} public void registerBeanDefinitions(Document doc, XmlReaderContext readerContext) {this.readerContext readerContext;this.logger.debug(Loading bean definitions);// 获取Document对象的root标签Element root doc.getDocumentElement();// 具体操作的方法this.doRegisterBeanDefinitions(root);
} protected void doRegisterBeanDefinitions(Element root) {BeanDefinitionParserDelegate parent this.delegate;this.delegate this.createDelegate(this.getReaderContext(), root, parent);// 对profile标签处理if (this.delegate.isDefaultNamespace(root)) {String profileSpec root.getAttribute(profile);if (StringUtils.hasText(profileSpec)) {String[] specifiedProfiles StringUtils.tokenizeToStringArray(profileSpec, ,; );if(!this.getReaderContext().getEnvironment().acceptsProfiles(specifiedProfiles)) {if (this.logger.isInfoEnabled()) {this.logger.info(Skipped XML bean definition file due to specified profiles [ profileSpec ] not matching: this.getReaderContext().getResource());}return;}}}// 解析配置文件之前的操作this.preProcessXml(root);// 解析配置文件this.parseBeanDefinitions(root, this.delegate);// 解析配置文件之后的操作this.postProcessXml(root);this.delegate parent;
} protected void parseBeanDefinitions(Element root, BeanDefinitionParserDelegate delegate) {if (delegate.isDefaultNamespace(root)) {// 获取根节点下的所有的直接子标签NodeList nl root.getChildNodes();// 循环获取每一个子标签for(int i 0; i nl.getLength(); i) {Node node nl.item(i);if (node instanceof Element) {Element ele (Element)node;if (delegate.isDefaultNamespace(ele)) {// 解析默认的标签this.parseDefaultElement(ele, delegate);} else {// 解析自定义的标签delegate.parseCustomElement(ele);}}}} else {delegate.parseCustomElement(root);}
} 默认标签 protected void processBeanDefinition(Element ele, BeanDefinitionParserDelegate delegate) {// 配置文件的解析BeanDefinitionHolder bdHolder delegate.parseBeanDefinitionElement(ele);if (bdHolder ! null) {bdHolder delegate.decorateBeanDefinitionIfRequired(ele, bdHolder);try {// 注册我们获取的 BeanDefinitionHolder 对象BeanDefinitionReaderUtils.registerBeanDefinition(bdHolder,this.getReaderContext().getRegistry());} catch (BeanDefinitionStoreException var5) {this.getReaderContext().error(Failed to register bean definitionwith name bdHolder.getBeanName() , ele, var5);}this.getReaderContext().fireComponentRegistered(newBeanComponentDefinition(bdHolder));}
} 具体的解析操作 public BeanDefinitionHolder parseBeanDefinitionElement(Element ele,BeanDefinition containingBean) {// 获取bean标签的id属性String id ele.getAttribute(id);// 获取bean标签的name属性String nameAttr ele.getAttribute(name);ListString aliases new ArrayList();if (StringUtils.hasLength(nameAttr)) {String[] nameArr StringUtils.tokenizeToStringArray(nameAttr, ,;);aliases.addAll(Arrays.asList(nameArr));}String beanName id;if (!StringUtils.hasText(id) !aliases.isEmpty()) {beanName (String)aliases.remove(0);if (this.logger.isDebugEnabled()) {this.logger.debug(No XML id specified - using beanName as bean name and aliases as aliases);}}if (containingBean null) {// 检查name是否唯一this.checkNameUniqueness(beanName, aliases, ele);}AbstractBeanDefinition beanDefinition this.parseBeanDefinitionElement(ele, beanName, containingBean);if (beanDefinition ! null) {if (!StringUtils.hasText(beanName)) {try {if (containingBean ! null) {beanName BeanDefinitionReaderUtils.generateBeanName(beanDefinition,this.readerContext.getRegistry(), true);} else {beanName this.readerContext.generateBeanName(beanDefinition);String beanClassName beanDefinition.getBeanClassName();if (beanClassName ! null beanName.startsWith(beanClassName) beanName.length() beanClassName.length() !this.readerContext.getRegistry().isBeanNameInUse(beanClassName)) {aliases.add(beanClassName);}}if (this.logger.isDebugEnabled()) {this.logger.debug(Neither XML id nor name specified - using generated bean name [ beanName ]);}} catch (Exception var9) {this.error(var9.getMessage(), ele);return null;}}String[] aliasesArray StringUtils.toStringArray(aliases);return new BeanDefinitionHolder(beanDefinition, beanName,aliasesArray);} else {return null;}
} 方法registerBeanDefinition public static void registerBeanDefinition(BeanDefinitionHolder definitionHolder, BeanDefinitionRegistry registry) throws BeanDefinitionStoreException {String beanName definitionHolder.getBeanName();// 关键代码registry.registerBeanDefinition(beanName,definitionHolder.getBeanDefinition());String[] aliases definitionHolder.getAliases();if (aliases ! null) {String[] var4 aliases;int var5 aliases.length;for(int var6 0; var6 var5; var6) {String alias var4[var6];registry.registerAlias(beanName, alias);}}
} 我们需要解析的信息要保存到我们前面实例化的BeanFactory的工厂对象中DefaultListableBeanFactory对象。 public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition) throws BeanDefinitionStoreException {Assert.hasText(beanName, Bean name must not be empty);Assert.notNull(beanDefinition, BeanDefinition must not be null);if (beanDefinition instanceof AbstractBeanDefinition) {try {((AbstractBeanDefinition)beanDefinition).validate();} catch (BeanDefinitionValidationException var9) {throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName, Validation of bean definition failed, var9);}}BeanDefinition oldBeanDefinition (BeanDefinition)this.beanDefinitionMap.get(beanName);if (oldBeanDefinition ! null) {if (!this.isAllowBeanDefinitionOverriding()) {throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName, Cannot register bean definition [ beanDefinition ] for bean beanName : There is already [ oldBeanDefinition ] bound.);}if (oldBeanDefinition.getRole() beanDefinition.getRole()) {if (this.logger.isWarnEnabled()) {this.logger.warn(Overriding user-defined bean definition for bean beanName with a framework-generated bean definition: replacing [ oldBeanDefinition ] with [ beanDefinition ]);}} else if (!beanDefinition.equals(oldBeanDefinition)) {if (this.logger.isInfoEnabled()) {this.logger.info(Overriding bean definition for bean beanName with a different definition: replacing [ oldBeanDefinition ] with [ beanDefinition ]);}} else if (this.logger.isDebugEnabled()) {this.logger.debug(Overriding bean definition for bean beanName with an equivalent definition: replacing [ oldBeanDefinition ] with [ beanDefinition ]);}this.beanDefinitionMap.put(beanName, beanDefinition);} else {if (this.hasBeanCreationStarted()) {synchronized(this.beanDefinitionMap) {this.beanDefinitionMap.put(beanName, beanDefinition);ListString updatedDefinitions new ArrayList(this.beanDefinitionNames.size() 1);updatedDefinitions.addAll(this.beanDefinitionNames);updatedDefinitions.add(beanName);this.beanDefinitionNames updatedDefinitions;if (this.manualSingletonNames.contains(beanName)) {SetString updatedSingletons new LinkedHashSet(this.manualSingletonNames);updatedSingletons.remove(beanName);this.manualSingletonNames updatedSingletons;}}} else {this.beanDefinitionMap.put(beanName, beanDefinition);this.beanDefinitionNames.add(beanName);this.manualSingletonNames.remove(beanName);}this.frozenBeanDefinitionNames null;}if (oldBeanDefinition ! null || this.containsSingleton(beanName)) {this.resetBeanDefinition(beanName);}}
} 关键结论SpringIoC容器启动的时候创建的BeanFactory对象的具体实例是(DefultListableBeanFactory)然后我们加载解析的配置文件中的相关标签会保存在BeanDefinition对象中而多个BeanDefinition对象最终都会保存在DefaultListableBeanFactory对象的beanDefinitionMap属性中。 Override
public void refresh() throws BeansException, IllegalStateException {//startupShutdownMonitor对象在spring环境刷新和销毁的时候都会用到确保刷新和销毁不会同时执行synchronized (this.startupShutdownMonitor) {// 准备工作例如记录事件设置标志检查环境变量等并有留给子类扩展的位置用来将属性加入到applicationContext中prepareRefresh();// 创建beanFactory这个对象作为applicationContext的成员变量可以被applicationContext拿来用,// 并且解析资源例如xml文件取得bean的定义放在beanFactory中ConfigurableListableBeanFactory beanFactory obtainFreshBeanFactory();// 对beanFactory做一些设置例如类加载器、SPEL解析器、指定bean的某些类型的成员变量对应某些对象.prepareBeanFactory(beanFactory);try {// 子类扩展用可以设置bean的后置处理器bean在实例化之后这些后置处理器会执行postProcessBeanFactory(beanFactory);// 执行beanFactory后置处理器有别于bean后置处理器处理bean实例beanFactory 后置处理器处理bean定义invokeBeanFactoryPostProcessors(beanFactory);// 将所有的bean的后置处理器排好序但不会马上用bean实例化之后会用到registerBeanPostProcessors(beanFactory);// 初始化国际化服务initMessageSource();// 创建事件广播器initApplicationEventMulticaster();// 空方法留给子类自己实现的在实例化bean之前做一些ApplicationContext相关的操作onRefresh();// 注册一部分特殊的事件监听器剩下的只是准备好名字留待bean实例化完成后再注册registerListeners();// 单例模式的bean的实例化、成员变量注入、初始化等工作都在此完成finishBeanFactoryInitialization(beanFactory);// applicationContext刷新完成后的处理例如生命周期监听器的回调广播通知等finishRefresh();}catch (BeansException ex) {logger.warn(Exception encountered during context initialization -cancelling refresh attempt, ex);// 刷新失败后的处理主要是将一些保存环境信息的集合做清理destroyBeans();// applicationContext是否已经激活的标志设置为falsecancelRefresh(ex);// Propagate exception to caller.throw ex;}}
} 3. Spring MVC 源码浅析 Spring MVC 源码分析的入口是 DispatcherServlet。因为他就是一个Servlet所以我们前提是要清楚Servlet的生命周期。 DispatcherServlet的类图结构 3.1 分析init方法 在父类的HttpServletBean中找到了对应的init方法。 public final void init() throws ServletException {if (this.logger.isDebugEnabled()) {this.logger.debug(Initializing servlet this.getServletName() );}try {PropertyValues pvs new HttpServletBean.ServletConfigPropertyValues(this.getServletConfig(),this.requiredProperties);BeanWrapper bw PropertyAccessorFactory.forBeanPropertyAccess(this);ResourceLoader resourceLoader new ServletContextResourceLoader(this.getServletContext());bw.registerCustomEditor(Resource.class, new ResourceEditor(resourceLoader,this.getEnvironment()));this.initBeanWrapper(bw);bw.setPropertyValues(pvs, true);} catch (BeansException var4) {this.logger.error(Failed to set bean properties on servlet this.getServletName() , var4);throw var4;}// 关键代码this.initServletBean();if (this.logger.isDebugEnabled()) {this.logger.debug(Servlet this.getServletName() configured successfully);}
} 进入initServletBean方法。 protected final void initServletBean() throws ServletException {this.getServletContext().log(Initializing Spring FrameworkServlet this.getServletName() );if (this.logger.isInfoEnabled()) {this.logger.info(FrameworkServlet this.getServletName() : initialization started);}long startTime System.currentTimeMillis();try {// 初始化 Web容器this.webApplicationContext this.initWebApplicationContext();// 预留给我们扩展的方法this.initFrameworkServlet();} catch (ServletException var5) {this.logger.error(Context initialization failed, var5);throw var5;} catch (RuntimeException var6) {this.logger.error(Context initialization failed, var6);throw var6;}if (this.logger.isInfoEnabled()) {long elapsedTime System.currentTimeMillis() - startTime;this.logger.info(FrameworkServlet this.getServletName() : initialization completed in elapsedTime ms);}
} protected WebApplicationContext initWebApplicationContext() {WebApplicationContext rootContext WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());WebApplicationContext wac null;// 如果找到了 rootContextif (this.webApplicationContext ! null) {wac this.webApplicationContext;if (wac instanceof ConfigurableWebApplicationContext) {ConfigurableWebApplicationContext cwac (ConfigurableWebApplicationContext)wac;if (!cwac.isActive()) {if (cwac.getParent() null) {cwac.setParent(rootContext);}this.configureAndRefreshWebApplicationContext(cwac);}}}if (wac null) {// 查找容器wac this.findWebApplicationContext();}if (wac null) {// 创建容器wac this.createWebApplicationContext(rootContext);}if (!this.refreshEventReceived) {// 刷新容器this.onRefresh(wac);}if (this.publishContext) {String attrName this.getServletContextAttributeName();this.getServletContext().setAttribute(attrName, wac);if (this.logger.isDebugEnabled()) {this.logger.debug(Published WebApplicationContext of servlet this.getServletName() as ServletContext attribute with name [ attrName ]);}}
return wac;
} createWebApplicationContext方法 protected WebApplicationContext createWebApplicationContext(ApplicationContext parent) {Class? contextClass this.getContextClass();if (this.logger.isDebugEnabled()) {this.logger.debug(Servlet with name this.getServletName() will try to create custom WebApplicationContext context of class contextClass.getName() , using parent context [ parent ]);}if(!ConfigurableWebApplicationContext.class.isAssignableFrom(contextClass)) {throw new ApplicationContextException(Fatal initialization error in servlet with name this.getServletName() : custom WebApplicationContext class [ contextClass.getName() ] is not of type ConfigurableWebApplicationContext);} else {ConfigurableWebApplicationContext wac (ConfigurableWebApplicationContext)BeanUtils.instantiateClass(contextClass);wac.setEnvironment(this.getEnvironment());wac.setParent(parent);wac.setConfigLocation(this.getContextConfigLocation());// 核心代码this.configureAndRefreshWebApplicationContext(wac);return wac;}
} configureAndRefreshWebApplicationContext方法 protected void configureAndRefreshWebApplicationContext(ConfigurableWebApplicationContext wac){if (ObjectUtils.identityToString(wac).equals(wac.getId())) {if (this.contextId ! null) {wac.setId(this.contextId);} else {wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX ObjectUtils.getDisplayString(this.getServletContext().getContextPath()) / this.getServletName());}}wac.setServletContext(this.getServletContext());wac.setServletConfig(this.getServletConfig());wac.setNamespace(this.getNamespace());wac.addApplicationListener(new SourceFilteringListener(wac, newFrameworkServlet.ContextRefreshListener()));ConfigurableEnvironment env wac.getEnvironment();if (env instanceof ConfigurableWebEnvironment) {((ConfigurableWebEnvironment)env).initPropertySources(this.getServletContext(), this.getServletConfig());}this.postProcessWebApplicationContext(wac);this.applyInitializers(wac);// 关键代码 完成SpringMVC配置文件的加载解析操作 Spring容器初始化操作wac.refresh();
} DispatcherServlet的初始化操作其实就是IoC容器的初始化操作过程完成了Spring MVC配置文件的加载解析操作。 3.2 分析service方法 protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {HttpMethod httpMethod HttpMethod.resolve(request.getMethod());if (HttpMethod.PATCH ! httpMethod httpMethod ! null) {super.service(request, response);} else {// 具体处理请求的方法this.processRequest(request, response);}
} protected final void processRequest(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {long startTime System.currentTimeMillis();Throwable failureCause null;LocaleContext previousLocaleContext LocaleContextHolder.getLocaleContext();LocaleContext localeContext this.buildLocaleContext(request);RequestAttributes previousAttributes RequestContextHolder.getRequestAttributes();ServletRequestAttributes requestAttributes this.buildRequestAttributes(request, response, previousAttributes);WebAsyncManager asyncManager WebAsyncUtils.getAsyncManager(request);asyncManager.registerCallableInterceptor(FrameworkServlet.class.getName(), new FrameworkServlet.RequestBindingInterceptor());this.initContextHolders(request, localeContext, requestAttributes);try {this.doService(request, response);} catch (ServletException var17) {failureCause var17;throw var17;} catch (IOException var18) {failureCause var18;throw var18;} catch (Throwable var19) {failureCause var19;throw new NestedServletException(Request processing failed,var19);} finally {this.resetContextHolders(request, previousLocaleContext,previousAttributes);if (requestAttributes ! null) {requestAttributes.requestCompleted();}if (this.logger.isDebugEnabled()) {if (failureCause ! null) {this.logger.debug(Could not complete request,(Throwable)failureCause);} else if (asyncManager.isConcurrentHandlingStarted()) {this.logger.debug(Leaving response open for concurrent processing);} else {this.logger.debug(Successfully completed request);}}this.publishRequestHandledEvent(request, response, startTime(Throwable)failureCause);}
} 具体处理请求 this.doService(request, response); protected void doService(HttpServletRequest request, HttpServletResponse response) throws Exception {if (this.logger.isDebugEnabled()) {String resumed WebAsyncUtils.getAsyncManager(request).hasConcurrentResult() ? resumed : ;this.logger.debug(DispatcherServlet with name this.getServletName() resumed processing request.getMethod() request for [ getRequestUri(request) ]);}MapString, Object attributesSnapshot null;if (WebUtils.isIncludeRequest(request)) {attributesSnapshot new HashMap();Enumeration attrNames request.getAttributeNames();label108:while(true) {String attrName;do {if (!attrNames.hasMoreElements()) {break label108;}attrName (String)attrNames.nextElement();} while(!this.cleanupAfterInclude !attrName.startsWith(org.springframework.web.servlet));attributesSnapshot.put(attrName,request.getAttribute(attrName));}}// 将Web容器保存到了 Request请求中request.setAttribute(WEB_APPLICATION_CONTEXT_ATTRIBUTE,this.getWebApplicationContext());request.setAttribute(LOCALE_RESOLVER_ATTRIBUTE, this.localeResolver);request.setAttribute(THEME_RESOLVER_ATTRIBUTE, this.themeResolver);request.setAttribute(THEME_SOURCE_ATTRIBUTE, this.getThemeSource());FlashMap inputFlashMap this.flashMapManager.retrieveAndUpdate(request, response);if (inputFlashMap ! null) {request.setAttribute(INPUT_FLASH_MAP_ATTRIBUTE,Collections.unmodifiableMap(inputFlashMap));}request.setAttribute(OUTPUT_FLASH_MAP_ATTRIBUTE, new FlashMap());request.setAttribute(FLASH_MAP_MANAGER_ATTRIBUTE, this.flashMapManager);try {// 处理请求分发this.doDispatch(request, response);} finally {if(!WebAsyncUtils.getAsyncManager(request).isConcurrentHandlingStarted()
attributesSnapshot ! null) {this.restoreAttributesAfterInclude(request, attributesSnapshot);}}
} protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {HttpServletRequest processedRequest request;HandlerExecutionChain mappedHandler null;boolean multipartRequestParsed false;WebAsyncManager asyncManager WebAsyncUtils.getAsyncManager(request);try {try {ModelAndView mv null;Object dispatchException null;try {// 检查是否有文件上传processedRequest this.checkMultipart(request);multipartRequestParsed processedRequest ! request;mappedHandler this.getHandler(processedRequest);if (mappedHandler null || mappedHandler.getHandler() null) {this.noHandlerFound(processedRequest, response);return;}HandlerAdapter ha this.getHandlerAdapter(mappedHandler.getHandler());String method request.getMethod();boolean isGet GET.equals(method);if (isGet || HEAD.equals(method)) {long lastModified ha.getLastModified(request,mappedHandler.getHandler());if (this.logger.isDebugEnabled()) {this.logger.debug(Last-Modified value for [ getRequestUri(request) ] is: lastModified);}if ((new ServletWebRequest(request,response)).checkNotModified(lastModified) isGet) {return;}}if (!mappedHandler.applyPreHandle(processedRequest,response)) {return;}mv ha.handle(processedRequest, response,mappedHandler.getHandler());if (asyncManager.isConcurrentHandlingStarted()) {return;}this.applyDefaultViewName(processedRequest, mv);mappedHandler.applyPostHandle(processedRequest, response,mv);} catch (Exception var20) {dispatchException var20;} catch (Throwable var21) {dispatchException new NestedServletException(Handler dispatch failed, var21);}this.processDispatchResult(processedRequest, response,mappedHandler, mv, (Exception)dispatchException);} catch (Exception var22) {this.triggerAfterCompletion(processedRequest, response,mappedHandler, var22);} catch (Throwable var23) {this.triggerAfterCompletion(processedRequest, response,mappedHandler, new NestedServletException(Handler processing failed, var23));}} finally {if (asyncManager.isConcurrentHandlingStarted()) {if (mappedHandler ! null) {mappedHandler.applyAfterConcurrentHandlingStarted(processedRequest, response);}} else if (multipartRequestParsed) {this.cleanupMultipart(processedRequest);}}
} 文件上传操作 protected HttpServletRequest checkMultipart(HttpServletRequest request) throws MultipartException {if (this.multipartResolver ! null this.multipartResolver.isMultipart(request)) {if (WebUtils.getNativeRequest(request, MultipartHttpServletRequest.class) ! null) {this.logger.debug(Request is already a MultipartHttpServletRequest - if not in a forward, this typically results from an additional MultipartFilter in web.xml);} else {if (!(request.getAttribute(javax.servlet.error.exception)instanceof MultipartException)) {// 文件上传操作的具体执行return this.multipartResolver.resolveMultipart(request);}this.logger.debug(Multipart resolution failed for current request before - skipping re-resolution for undisturbed error rendering);}}return request;
} public MultipartHttpServletRequest resolveMultipart(final HttpServletRequest request) throws MultipartException {Assert.notNull(request, Request must not be null);// 是否需要延迟 处理if (this.resolveLazily) {return new DefaultMultipartHttpServletRequest(request) {protected void initializeMultipart() {MultipartParsingResult parsingResult CommonsMultipartResolver.this.parseRequest(request);this.setMultipartFiles(parsingResult.getMultipartFiles());this.setMultipartParameters(parsingResult.getMultipartParameters());this.setMultipartParameterContentTypes(parsingResult.getMultipartParameterContentTypes());}};} else {// 解析请求MultipartParsingResult parsingResult this.parseRequest(request);return new DefaultMultipartHttpServletRequest(request,parsingResult.getMultipartFiles(), parsingResult.getMultipartParameters(),parsingResult.getMultipartParameterContentTypes());}
} protected MultipartParsingResult parseRequest(HttpServletRequest request)throws MultipartException {String encoding this.determineEncoding(request);FileUpload fileUpload this.prepareFileUpload(encoding);try {// 获取提交的表单中的所有的表单域ListFileItem fileItems ((ServletFileUpload)fileUpload).parseRequest(request);// 解析每一个表单域return this.parseFileItems(fileItems, encoding);} catch (SizeLimitExceededException var5) {throw new MaxUploadSizeExceededException(fileUpload.getSizeMax(),var5);} catch (FileSizeLimitExceededException var6) {throw new MaxUploadSizeExceededException(fileUpload.getFileSizeMax(), var6);} catch (FileUploadException var7) {throw new MultipartException(Failed to parse multipart servlet request, var7);}
} 具体处理表单中提交的各个部分 protected CommonsFileUploadSupport.MultipartParsingResult parseFileItems(ListFileItem fileItems, String encoding) {MultiValueMapString, MultipartFile multipartFiles new LinkedMultiValueMap();MapString, String[] multipartParameters new HashMap();MapString, String multipartParameterContentTypes new HashMap();Iterator var6 fileItems.iterator();while(true) {while(var6.hasNext()) {FileItem fileItem (FileItem)var6.next();// 普通表单域处理if (fileItem.isFormField()) {String partEncoding this.determineEncoding(fileItem.getContentType(), encoding);String value;if (partEncoding ! null) {try {// 获取对应的编码方式value fileItem.getString(partEncoding);} catch (UnsupportedEncodingException var12) {if (this.logger.isWarnEnabled()) {this.logger.warn(Could not decode multipartitem fileItem.getFieldName() with encoding partEncoding : using platform default);}value fileItem.getString();}} else {// 得到提交的值value fileItem.getString();}String[] curParam (String[])multipartParameters.get(fileItem.getFieldName());if (curParam null) {// 将提交的数据保存起来multipartParameters.put(fileItem.getFieldName(), new String[]{value});} else {String[] newParam StringUtils.addStringToArray(curParam, value);multipartParameters.put(fileItem.getFieldName(),newParam);}multipartParameterContentTypes.put(fileItem.getFieldName(), fileItem.getContentType());} else {// 表单提交的文件信息CommonsMultipartFile file new CommonsMultipartFile(fileItem);// 将表单提交的文件信息 封装到了 CommonsMultipartFile 对象中multipartFiles.add(file.getName(), file);if (this.logger.isDebugEnabled()) {this.logger.debug(Found multipart file [ file.getName() ] of size file.getSize() bytes with original filename [ file.getOriginalFilename() ], stored file.getStorageDescription());}}}return new CommonsFileUploadSupport.MultipartParsingResult(multipartFiles, multipartParameters, multipartParameterContentTypes);}
} 文件上传处理完成 继续回到doDispatch方法中 protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {HttpServletRequest processedRequest request;HandlerExecutionChain mappedHandler null;boolean multipartRequestParsed false;WebAsyncManager asyncManager WebAsyncUtils.getAsyncManager(request);try {try {ModelAndView mv null;Object dispatchException null;try {// 检查是否有文件上传processedRequest this.checkMultipart(request);multipartRequestParsed processedRequest ! request;// 处理器映射器mappedHandler this.getHandler(processedRequest);if (mappedHandler null || mappedHandler.getHandler() null) {this.noHandlerFound(processedRequest, response);return;}// 获取处理器适配器HandlerAdapter ha this.getHandlerAdapter(mappedHandler.getHandler());String method request.getMethod();boolean isGet GET.equals(method);if (isGet || HEAD.equals(method)) {long lastModified ha.getLastModified(request,mappedHandler.getHandler());if (this.logger.isDebugEnabled()) {this.logger.debug(Last-Modified value for [ getRequestUri(request) ] is: lastModified);}if ((new ServletWebRequest(request, response)).checkNotModified(lastModified) isGet) {return;}}if (!mappedHandler.applyPreHandle(processedRequest,response)) {return;}// 处理适配器处理请求mv ha.handle(processedRequest, response,mappedHandler.getHandler());if (asyncManager.isConcurrentHandlingStarted()) {return;}this.applyDefaultViewName(processedRequest, mv);mappedHandler.applyPostHandle(processedRequest, response,mv);} catch (Exception var20) {dispatchException var20;} catch (Throwable var21) {dispatchException new NestedServletException(Handlerdispatch failed, var21);}this.processDispatchResult(processedRequest, response,mappedHandler, mv, (Exception)dispatchException);} catch (Exception var22) {this.triggerAfterCompletion(processedRequest, response, mappedHandler, var22);} catch (Throwable var23) {this.triggerAfterCompletion(processedRequest, response, mappedHandler, new NestedServletException(Handler processing failed, var23));}} finally {if (asyncManager.isConcurrentHandlingStarted()) {if (mappedHandler ! null) {mappedHandler.applyAfterConcurrentHandlingStarted(processedRequest, response);}} else if (multipartRequestParsed) {this.cleanupMultipart(processedRequest);}}
} 基于普通的使用方式 public ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {return ((Controller)handler).handleRequest(request, response);
} 通过源码的简单分析论证了我们前面给大家介绍的Spring MVC的工作原理。 4. Spring MVC和Spring IoC的关联关系 Spring容器是一个父容器SpringMVC容器是一个子容器它继承自Spring容器。因此在SpringMVC容器中可以访问到Spring容器中定义的Bean而在Spring容器中无法访问SpringMVC容器中定义的Bean。在Web开发中Controller全部在SpringMVC中扫描除了Controller之外的Bean全部在Spring容器中扫描Service、Dao按这种方式扫描扫描完完成后Controller可以访问到Service。 1. 为什么不全部都在Spring中扫描 因为处理器映射器只会去SpringMVC中查找到Controller如果没有就找不到不会去 Spring中找这就决定了Controller必须在SpringMVC中扫描。 2. 为什么不全部在SpringMVC中扫描 在SSM整合或者SpringSpringMVCJdbcTemplate中可以全部在SpringMVC中扫描但是在SSH整合中这种方式不允许。 分析Spring的初始化应该从web.xml中入手。 !-- 配置Spring --
context-paramparam-namecontextConfigLocation/param-nameparam-valueclasspath:applicationContext.xml/param-value
/context-param
listenerlistenerclassorg.springframework.web.context.ContextLoaderListener/listener-class
/listener ContextLoaderListener这个监听器是系统启动的时候会触发。 public void contextInitialized(ServletContextEvent event) {// 初始化web容器this.initWebApplicationContext(event.getServletContext());
} public WebApplicationContext initWebApplicationContext(ServletContext servletContext) {if(servletContext.getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE) ! null) {throw new IllegalStateException(Cannot initialize context because there is already a root application context present - check whether you have multiple ContextLoader* definitions in your web.xml!);} else {Log logger LogFactory.getLog(ContextLoader.class);servletContext.log(Initializing Spring root WebApplicationContext);if (logger.isInfoEnabled()) {logger.info(Root WebApplicationContext: initialization started);}long startTime System.currentTimeMillis();try {if (this.context null) {// 创建容器对象this.context this.createWebApplicationContext(servletContext);}if (this.context instanceof ConfigurableWebApplicationContext) {ConfigurableWebApplicationContext cwac (ConfigurableWebApplicationContext)this.context;if (!cwac.isActive()) {if (cwac.getParent() null) {ApplicationContext parent this.loadParentContext(servletContext);cwac.setParent(parent);}// 完全Spring IoC容器的初始化操作this.configureAndRefreshWebApplicationContext(cwac, servletContext);}}// 将Spring的IoC容器对象保存在了Servlet容器中 key是ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, this.context);ClassLoader ccl Thread.currentThread().getContextClassLoader();if (ccl ContextLoader.class.getClassLoader()) {currentContext this.context;} else if (ccl ! null) {currentContextPerThread.put(ccl, this.context);}if (logger.isDebugEnabled()) {logger.debug(Published root WebApplicationContext as ServletContext attribute with name [ WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE ]);}if (logger.isInfoEnabled()) {long elapsedTime System.currentTimeMillis() - startTime;logger.info(Root WebApplicationContext: initialization completed in elapsedTime ms);}return this.context;} catch (RuntimeException var8) {logger.error(Context initialization failed, var8);servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, var8);throw var8;} catch (Error var9) {logger.error(Context initialization failed, var9);servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, var9);throw var9;}
}在SpringMVC整合Spring中在ContextLoaderListener完成的是SpringIoC的初始化操作同时将IoC容器保存在了Servlet上下文中。 再看SpringMVC中的处理 protected WebApplicationContext initWebApplicationContext() {// 获取Spring IoC容器对象WebApplicationContext rootContext WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());WebApplicationContext wac null;if (this.webApplicationContext ! null) {wac this.webApplicationContext;if (wac instanceof ConfigurableWebApplicationContext) {ConfigurableWebApplicationContext cwac (ConfigurableWebApplicationContext)wac;if (!cwac.isActive()) {if (cwac.getParent() null) {cwac.setParent(rootContext);}this.configureAndRefreshWebApplicationContext(cwac);}}}if (wac null) {wac this.findWebApplicationContext();}if (wac null) {wac this.createWebApplicationContext(rootContext);}if (!this.refreshEventReceived) {this.onRefresh(wac);}if (this.publishContext) {String attrName this.getServletContextAttributeName();this.getServletContext().setAttribute(attrName, wac);if (this.logger.isDebugEnabled()) {this.logger.debug(Published WebApplicationContext of servlet this.getServletName() as ServletContext attribute with name [ attrName ]);}}return wac;
} 如何获取Spring IoC容器对象的。 public static WebApplicationContext getWebApplicationContext(ServletContext sc){return getWebApplicationContext(sc,WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
} 然后进入createWebApplicationContext方法。 protected WebApplicationContext createWebApplicationContext(ApplicationContext parent) {Class? contextClass this.getContextClass();if (this.logger.isDebugEnabled()) {this.logger.debug(Servlet with name this.getServletName() will try to create custom WebApplicationContext context of class contextClass.getName() , using parent context [ parent ]);}if(!ConfigurableWebApplicationContext.class.isAssignableFrom(contextClass)) {throw new ApplicationContextException(Fatal initialization error in servlet with name this.getServletName() : custom WebApplicationContext class [ contextClass.getName() ] is not of type ConfigurableWebApplicationContext);} else {ConfigurableWebApplicationContext wac (ConfigurableWebApplicationContext)BeanUtils.instantiateClass(contextClass);wac.setEnvironment(this.getEnvironment());// Spring MVC的IoC容器对象设置Spring 的IoC容器对象为父容器wac.setParent(parent);wac.setConfigLocation(this.getContextConfigLocation());this.configureAndRefreshWebApplicationContext(wac);return wac;}
} 得出的重点结论Spring的IoC容器对象是SpringMVC容器的父容器所以SpringMVC中的对象可以将SpringIOC容器中的对象注入但是反过来就不行了 五、Spring和SpringMVC总结 相关专题常见面试题 1. 介绍下Spring的IoC 2. 介绍下Spring的AOP 3. 事务的传播属性 4. 事务的隔离级别 5. 介绍下Spring中用到的设计模式有哪些 6. 介绍下Spring MVC的工作原理 7. Spring和SpringMVC的关系
