深圳团购网站设计公司,网站建设排行公司,云游戏网站在线玩,wordpress安装php5.4上篇说的是无需半行xml配置完成bean的自动化注入。这篇仍然不要任何xml配置#xff0c;通过Java代码也能达到同样的效果。 这么说#xff0c;是要把上篇的料拿出来再煮一遍#xff1f; 当然不是#xff0c;上篇我们几乎都在用注解的方式如ComponentScan Component等就完成了… 上篇说的是无需半行xml配置完成bean的自动化注入。这篇仍然不要任何xml配置通过Java代码也能达到同样的效果。 这么说是要把上篇的料拿出来再煮一遍 当然不是上篇我们几乎都在用注解的方式如ComponentScan Component等就完成了自动化注入但是这些注解不是无所不能的有些地方它也是望尘莫及的比如第三方类库你总不能跑到人家jar包或者库里面悄悄的加上这些注解再伪装成原来的样子用吧太丑了 所以Spring可以通过显示配置的方式来解决第一种前面有介绍过就是通过xml来显示声明bean第二种就是这里要介绍的基于Java代码方式装配bean。 基于注解的自动化注入固然优雅但是它也有鞭长莫及的时候这时候就来看看Java代码如何装配bean的。 还记的上篇的配置类CDPlayerConfig是长这样的 Configuration
ComponentScan
public class CDPlayerConfig {
}有了这个万能的组件扫描注解一切都是那么只能只需要在bean类上加上如Component注解Spring就会自动为该类创建相应的bean类。 但是现在因为我们有一些第三方类库我们没办法去深入类中加上这些标记了所以ComponentScan就失去了威力和意义。 这篇的CDPlayerConfig应该长这样 Configuration
public class CDPlayerConfig {
}Configuration注解表示该类是一个配置类。显然要创建的bean的信息是要放到这个类中的。 基于其他类以及类中的方法不变比如CompactDisc, CDPlayer, SgtPeppers等。编写测试方法如下 RunWith(SpringJUnit4ClassRunner.class)
ContextConfiguration(classesCDPlayerConfig.class)
public class CDPlayerTest {Rulepublic final StandardOutputStreamLog log new StandardOutputStreamLog();Autowiredprivate MediaPlayer player;Autowiredprivate CompactDisc cd;Testpublic void cdShouldNotBeNull() {assertNotNull(cd);}Testpublic void play() {player.play();assertEquals(Playing Sgt. Peppers Lonely Hearts Club Band by The Beatles\r\n,log.getLog());}}首先从代码来看就会出现如下的注入错误 这里显示MediaPlayer无法注入。同时运行程序得到结果如下 Testing started at 0:20 ...
0:20:03: Executing external tasks cleanTest test...
:cleanTest
:compileJava
:processResources UP-TO-DATE
:classes
:compileTestJava
:processTestResources UP-TO-DATE
:testClasses
:test
一月 15, 2017 12:20:06 上午 org.springframework.test.context.TestContextManager retrieveTestExecutionListeners
信息: Could not instantiate TestExecutionListener [org.springframework.test.context.web.ServletTestExecutionListener]. Specify custom listener classes or make the default listener classes (and their required dependencies) available. Offending class: [javax/servlet/ServletContext]
一月 15, 2017 12:20:06 上午 org.springframework.test.context.TestContextManager retrieveTestExecutionListeners
信息: Could not instantiate TestExecutionListener [org.springframework.test.context.transaction.TransactionalTestExecutionListener]. Specify custom listener classes or make the default listener classes (and their required dependencies) available. Offending class: [org/springframework/transaction/interceptor/TransactionAttributeSource]
一月 15, 2017 12:20:06 上午 org.springframework.context.support.GenericApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.GenericApplicationContext6adf0b01: startup date [Sun Jan 15 00:20:06 CST 2017]; root of context hierarchy
一月 15, 2017 12:20:06 上午 org.springframework.test.context.TestContextManager prepareTestInstance
严重: Caught exception while allowing TestExecutionListener [org.springframework.test.context.support.DependencyInjectionTestExecutionListener61c715e8] to prepare test instance [soundsystem.CDPlayerTest1081b08c]
org.springframework.beans.factory.BeanCreationException: Error creating bean with name soundsystem.CDPlayerTest: Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private soundsystem.MediaPlayer soundsystem.CDPlayerTest.player; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [soundsystem.MediaPlayer] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {org.springframework.beans.factory.annotation.Autowired(requiredtrue)}at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:293)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1186)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireBeanProperties(AbstractAutowireCapableBeanFactory.java:384)at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:110)at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:75)at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:331)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:213)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:290)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:292)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:233)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)at org.junit.runners.ParentRunner.run(ParentRunner.java:309)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:176)at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.runTestClass(JUnitTestClassExecuter.java:105)at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.execute(JUnitTestClassExecuter.java:56)at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassProcessor.processTestClass(JUnitTestClassProcessor.java:64)at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:50)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:497)at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)at org.gradle.messaging.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:32)at org.gradle.messaging.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:106)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:497)at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)at org.gradle.messaging.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:360)at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:54)at org.gradle.internal.concurrent.StoppableExecutorImpl$1.run(StoppableExecutorImpl.java:40)at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)at java.lang.Thread.run(Thread.java:745)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private soundsystem.MediaPlayer soundsystem.CDPlayerTest.player; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [soundsystem.MediaPlayer] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {org.springframework.beans.factory.annotation.Autowired(requiredtrue)}at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:509)at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:290)... 46 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [soundsystem.MediaPlayer] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {org.springframework.beans.factory.annotation.Autowired(requiredtrue)}at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1118)at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:967)at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:862)at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:481)... 48 moreError creating bean with name soundsystem.CDPlayerTest: Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private soundsystem.MediaPlayer soundsystem.CDPlayerTest.player; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [soundsystem.MediaPlayer] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {org.springframework.beans.factory.annotation.Autowired(requiredtrue)}
org.springframework.beans.factory.BeanCreationException: Error creating bean with name soundsystem.CDPlayerTest: Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private soundsystem.MediaPlayer soundsystem.CDPlayerTest.player; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [soundsystem.MediaPlayer] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {org.springframework.beans.factory.annotation.Autowired(requiredtrue)}at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:293)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1186)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireBeanProperties(AbstractAutowireCapableBeanFactory.java:384)at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:110)at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:75)at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:331)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:213)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:290)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:292)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:233)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)at org.junit.runners.ParentRunner.run(ParentRunner.java:309)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:176)at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.runTestClass(JUnitTestClassExecuter.java:105)at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.execute(JUnitTestClassExecuter.java:56)at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassProcessor.processTestClass(JUnitTestClassProcessor.java:64)at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:50)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:497)at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)at org.gradle.messaging.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:32)at org.gradle.messaging.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:106)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:497)at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)at org.gradle.messaging.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:360)at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:54)at org.gradle.internal.concurrent.StoppableExecutorImpl$1.run(StoppableExecutorImpl.java:40)at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)at java.lang.Thread.run(Thread.java:745)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private soundsystem.MediaPlayer soundsystem.CDPlayerTest.player; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [soundsystem.MediaPlayer] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {org.springframework.beans.factory.annotation.Autowired(requiredtrue)}at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:509)at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:290)... 46 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [soundsystem.MediaPlayer] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {org.springframework.beans.factory.annotation.Autowired(requiredtrue)}at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1118)at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:967)at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:862)at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:481)... 48 moresoundsystem.CDPlayerTest play FAILEDorg.springframework.beans.factory.BeanCreationExceptionCaused by: org.springframework.beans.factory.BeanCreationExceptionCaused by: org.springframework.beans.factory.NoSuchBeanDefinitionException
1 test completed, 1 failed
:test FAILED
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task :test.There were failing tests. See the report at: file:///C:/Users/Administrator/Desktop/spring_video/SpringiA4_SourceCode/Chapter_02/stereo-javaconfig/build/reports/tests/index.html
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
BUILD FAILED
Total time: 4.59 secs
There were failing tests. See the report at: file:///C:/Users/Administrator/Desktop/spring_video/SpringiA4_SourceCode/Chapter_02/stereo-javaconfig/build/reports/tests/index.html究其原因主要是既没有在xml中没有声明相应的bean也没有添加ComponentScan启动自动扫描组件机制。 所以这里还是需要在CDPlayerConfig配置类中做文章。 声明bean 通过注解Bean声明一个bean对象。 Beanpublic CompactDisc compactDisc() {return new SgtPeppers();}该声明好比在xml中添加 bean idsgtPeppers classsoundsystem.SgtPeppers/ 通过这种方式Spring会默认为SgtPeppers创建一个名为sgtPeppers的bean如果你想换个名字只需要在Bean后面加上类似(namelonelyHeartClubBand)这样的属性即可。 如果你的野心远不止满足于通过Java代码创建一个bean的话其实你还试试如何在CDPlayer中播放CompactDisc那就需要在CDPlayer中注入CompactDisc的bean了。于是我们可以这样声明 Beanpublic CDPlayer cdPlayer(CompactDisc compactDisc) {return new CDPlayer(compactDisc);}加上Bean注解表明cdPlayer()方法会创建一个bean实例并将其注册到Spring的应用上下文中显然bean的名字默认就是cdPlayer。在执行这个方法的时候Spring会拦截所有对方法的调用当然这里会传入Spring注册好的CompactDisc的实例bean给cdPlayer方法来确保返回的是创建好的cdPlayer的bean。注意这里的bean是单例的其实在xml中配置的bean如果没有特殊声明默认也是单例的。也就是说即使这里创建了多个类似cdPlayer的方法得到的仍然是同一个cdPlayer的bean。 这时候运行测试类CDPlayerTest RunWith(SpringJUnit4ClassRunner.class)
ContextConfiguration(classesCDPlayerConfig.class)
public class CDPlayerTest {Rulepublic final StandardOutputStreamLog log new StandardOutputStreamLog();Autowiredprivate MediaPlayer player;Testpublic void play() {player.play();assertEquals(Playing Sgt. Peppers Lonely Hearts Club Band by The Beatles\r\n,log.getLog());}}测试通过。 表明CDPlayer注入成功。前面通过Java代码注册的Bean有效。 如果您觉得阅读本文对您有帮助请点一下“推荐”按钮您的“推荐”将是我最大的写作动力如果您想持续关注我的文章请扫描二维码关注JackieZheng的微信公众号我会将我的文章推送给您并和您一起分享我日常阅读过的优质文章。 转载于:https://www.cnblogs.com/bigdataZJ/p/SpringInAction2.html
