有那些专门做职业统计的网站,网站防盗链怎么做,附近免费手工活拿回家,免费深圳企业名录这个以前分析过了#xff0c;但是再看的时候感觉写的太乱了(流水账)#xff0c;这个是精简版本。 bug复现
先上bug#xff0c;众所周知#xff0c;spring通过实例化和属性注入分开解决了循环依赖#xff0c;理论上也不会有问题。但是意外就那么来了#xff0c;经过排查是… 这个以前分析过了但是再看的时候感觉写的太乱了(流水账)这个是精简版本。 bug复现
先上bug众所周知spring通过实例化和属性注入分开解决了循环依赖理论上也不会有问题。但是意外就那么来了经过排查是Async导致报错如下所示。
java.lang.IllegalStateException: Failed to load ApplicationContextat org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:132)at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:124)at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:190)at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:132)at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:244)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:227)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:246)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)at org.junit.runners.ParentRunner.run(ParentRunner.java:413)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)at org.junit.runner.JUnitCore.run(JUnitCore.java:137)at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name testA: Bean with name testA has been injected into other beans [testB] in its raw version as part of a circular reference, but has eventually been wrapped. This means that said other beans do not use the final version of the bean. This is often the result of over-eager type matching - consider using getBeanNamesForType with the allowEagerInit flag turned off, for example.at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:631)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524)at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335)at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333)at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:944)at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918)at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583)at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:769)at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:761)at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:426)at org.springframework.boot.SpringApplication.run(SpringApplication.java:326)at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:123)at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99)at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124)... 25 more
源码分析
引发原因
简单的说BeanA为了解决循环依赖实例化后注入给了BeanBBeanB实例化属性注入完后轮到BeanA属性注入注入完后的引用和注入给BeanB的引用不一致了封装了一层代理spring就报错了 Aop为没有
不走循环依赖的Aop分析
抛开源码不看async如果有问题理论上aop也有问题都是返回代理你说对吧。但是如果aop没有问题aop对循环依赖做了特殊处理这里先分析下正常aop代理懂哥可以跳过 如果没有循环依赖那么也是通过AbstractAutoProxyCreator::applyBeanPostProcessorsAfterInitialization来创建的
走依循环依赖的Aop分析
如果遇到依赖循环那么就会在实例化的时候就创建代理了这里还有一个重要的就是他会把依赖循环中创建代理的bean给缓存起来图中已经标注了后续执行到applyBeanPostProcessorsAfterInitialization的时候也不会再创建一遍代理而是跳过 再回到最上层简单的分析下
属性注入完成引用地址是一样的代理对象引用在缓存中
通过一个简单的if判断换下指针就可以给spring容器交差了。
至此aop分析完成
Async分析
翻阅了AsyncAnnotationBeanPostProcessor没有实现SmartInstantiationAwareBeanPostProcessor 创建代理对象都是在applyBeanPostProcessorsAfterInitialization中创建的 总结
原理总结
AsyncAnnotationBeanPostProcessor未做特殊处理
解决方案
网上解决方案很多
Lazy不使用Async自己用线程池实现解决循环依赖
