专业做网站联系电话,wordpress做网店,制作微信公众号的网站,凡科网上传网站转载自 Spring Boot自动配置原理、实战
Spring Boot自动配置原理
Spring Boot的自动配置注解是EnableAutoConfiguration#xff0c;从上面的Import的类可以找到下面自动加载自动配置的映射。
org.springframework.core.io.support.SpringFactoriesLoader.loadFactoryNames(Cla…转载自 Spring Boot自动配置原理、实战
Spring Boot自动配置原理
Spring Boot的自动配置注解是EnableAutoConfiguration从上面的Import的类可以找到下面自动加载自动配置的映射。
org.springframework.core.io.support.SpringFactoriesLoader.loadFactoryNames(Class?, ClassLoader)
public static ListString loadFactoryNames(Class? factoryClass, ClassLoader classLoader) {String factoryClassName factoryClass.getName();try {EnumerationURL urls (classLoader ! null ? classLoader.getResources(FACTORIES_RESOURCE_LOCATION) :lassLoader.getSystemResources(FACTORIES_RESOURCE_LOCATION));ListString result new ArrayListString();while (urls.hasMoreElements()) {URL url urls.nextElement();Properties properties PropertiesLoaderUtils.loadProperties(new UrlResource(url));String factoryClassNames properties.getProperty(factoryClassName);result.addAll(Arrays.asList(StringUtils.commaDelimitedListToStringArray(factoryClassNames)));}return result;}catch (IOException ex) {throw new IllegalArgumentException(Unable to load [ factoryClass.getName() ] factories from location [ FACTORIES_RESOURCE_LOCATION ], ex);}
}
这个方法会加载类路径及所有jar包下META-INF/spring.factories配置中映射的自动配置的类。
/*** The location to look for factories.* pCan be present in multiple JAR files.*/
public static final String FACTORIES_RESOURCE_LOCATION META-INF/spring.factories;
查看Spring Boot自带的自动配置的包spring-boot-autoconfigure-1.5.6.RELEASE.jar打开其中的META-INF/spring.factories文件会找到自动配置的映射。
# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration\
org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\
org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\
org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration,\
org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration,\
org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration,\
org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration,\
org.springframework.boot.autoconfigure.cloud.CloudAutoConfiguration,\
...
再来看看数据源自动配置的实现注解
Configuration
ConditionalOnClass({ DataSource.class, EmbeddedDatabaseType.class })
EnableConfigurationProperties(DataSourceProperties.class)
Import({ Registrar.class, DataSourcePoolMetadataProvidersConfiguration.class })
public class DataSourceAutoConfiguration {
...
Configuration,ConditionalOnClass就是自动配置的核心首先它得是一个配置文件其次根据类路径下是否有这个类去自动配置。
自动配置实战
所以了解了自动配置的原理来自己实现一个自动配置的玩意其实很简单。
添加配置类
import org.slf4j.Logger;
import org.springframework.context.EnvironmentAware;
import org.springframework.core.env.Environment;import com.oceanpayment.common.utils.logger.LoggerUtils;public class EnvConfig implements EnvironmentAware {private final Logger logger LoggerUtils.getLogger(this);private Environment env;public String getStringValue(String key) {return env.getProperty(key);}public Long getLongValue(String key) {String value getStringValue(key);try {return Long.parseLong(value);} catch (Exception e) {logger.error(字符串转换Long失败{} {}, key, value);}return 0L;}public int getIntValue(String key) {return getLongValue(key).intValue();}Overridepublic void setEnvironment(Environment environment) {this.env environment;}}
添加自动配置类
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.PropertyResolver;Configuration
ConditionalOnClass(PropertyResolver.class)
public class EnvAutoConfig {Beanpublic EnvConfig envConfig() {return new EnvConfig();}}
创建META-INF/spring.factories文件添加自动配置映射
org.springframework.boot.autoconfigure.EnableAutoConfiguration\\
com.oceanpayment.common.config.env.EnvAutoConfig
这样就搞定了。
查看自动配置报告
怎么查看自己加的自动配置类有没有被加载或者查看所有自动配置激活的和未激活的可以通过以下几种试查看。
spring-boot:run运行的在对话框Enviroment中加入debugtrue变量 java -jar xx.jar --debugmain方法运行在VM Argumanets加入-Ddebug直接在application文件中加入debugtrue如果集成了spring-boot-starter-actuator监控通过autoconfig端点也可以查看。
启动后会在控制台看到以下自动配置报告信息AUTO-CONFIGURATION REPORTPositive matches:
-----------------AopAutoConfiguration matched:- ConditionalOnClass found required classes org.springframework.context.annotation.EnableAspectJAutoProxy, org.aspectj.lang.annotation.Aspect, org.aspectj.lang.reflect.Advice; ConditionalOnMissingClass did not find unwanted class (OnClassCondition)- ConditionalOnProperty (spring.aop.autotrue) matched (OnPropertyCondition)...EnvAutoConfig matched:- ConditionalOnClass found required class org.springframework.core.env.PropertyResolver; ConditionalOnMissingClass did not find unwanted class (OnClassCondition)ErrorMvcAutoConfiguration matched:- ConditionalOnClass found required classes javax.servlet.Servlet, org.springframework.web.servlet.DispatcherServlet; ConditionalOnMissingClass did not find unwanted class (OnClassCondition)- ConditionalOnWebApplication (required) found StandardServletEnvironment (OnWebApplicationCondition)ErrorMvcAutoConfiguration#basicErrorController matched:- ConditionalOnMissingBean (types: org.springframework.boot.autoconfigure.web.ErrorController; SearchStrategy: current) did not find any beans (OnBeanCondition)...Negative matches:
-----------------ActiveMQAutoConfiguration:Did not match:- ConditionalOnClass did not find required classes javax.jms.ConnectionFactory, org.apache.activemq.ActiveMQConnectionFactory (OnClassCondition)AopAutoConfiguration.JdkDynamicAutoProxyConfiguration:Did not match:- ConditionalOnProperty (spring.aop.proxy-target-classfalse) found different value in property proxy-target-class (OnPropertyCondition)ArtemisAutoConfiguration:Did not match:- ConditionalOnClass did not find required classes javax.jms.ConnectionFactory, org.apache.activemq.artemis.jms.client.ActiveMQConnectionFactory (OnClassCondition)BatchAutoConfiguration:Did not match:- ConditionalOnClass did not find required class org.springframework.batch.core.launch.JobLauncher (OnClassCondition)...
Positive matches已经启用的自动配置
Negative matches未启用的自动配置
从报告中看到自己添加的EnvAutoConfig已经自动配置了。
