Spirng 循环依赖报错：Is there an unresolvable circular reference?

Posted 2023-04-09

参考技术A

最近在项目中遇到了一次循环依赖报错的问题，虽然解决的很快，但是有些不明白的地方，特此记录。
在此我把 bean 的结构和 注入方式单独拎出来进行演示

点击进入 stack overflow 问题描述

BrokenComponent：

TolenComponent：

TubunComponent：

TwConfig：

DenpaComponent：

除了 tubunComponent 是构造器注入，其他的bean 都是set 注入。
分析bean依赖图可以发现确实是循环依赖的问题。

由于本人对spring bean 的加载机制不是很清晰，这次特意花了几天时间做了梳理。

解决了什么问题？

推荐博客：https://cloud.tencent.com/developer/article/1497692

作用：对通过 BeanFactory 创建的 bean 进行属性填充。

这是AbstractAutowireCapableBeanFactory#populateBean 方法中的某一段代码：

我打出了所有要进行轮询校验的 BeanPostProcessor

brokenComponent 中有两个bean:

一个是通过@Resource 注解注入的，一个是通过@Autowire 进行注入的，奉劝各位同学千万不要两种混用啊！！！

通过翻译及反复debug验证，这个类将对某个bean中所有被 @Resource 注解修饰的属性进行填充。

这个类将对某个bean中所有被 @Autowire@Value 注解修饰的属性进行填充。

1：无论使用@Resource 还是 @Resource，都不影响bean的初始化顺序。

2：@Resource修饰的属性 要优先于 @Autowire修饰的属性 进行初始化。

可以看到 tubunComponent 进行了两次 getSingleton，经过循环依赖检查的时候报错了。

1：Spring 容器先加载 brokenComponent 这个 bean。

2：brokenComponent依赖了tubunComponent（@Resource修饰），因此优先填充 tubunComponent，因此去初始化tubunComponent 这个bean，并将tubunComponent 存放在 DefaultSingletonBeanRegistry.singletonsCurrentlyInCreation 集合中。

3：tubunComponent依赖了depenComponent，因此去初始化depenComponent 这个bean，并将depenComponent 存放在 DefaultSingletonBeanRegistry.singletonsCurrentlyInCreation 集合中。

4：depenComponent依赖了tolenComponent，因此去初始化depenComponent 这个bean，并将tolenComponent 存放在 DefaultSingletonBeanRegistry.singletonsCurrentlyInCreation 集合中。

5：tolenComponent依赖了tubunComponent，因此去初始化tubunComponent 这个bean， 然而当将tubunComponent 存放在 DefaultSingletonBeanRegistry.singletonsCurrentlyInCreation 集合中时发现 tubunComponent 已经存在了，
从而判断这几个bean 产生了循环依赖并跑出异常。

beforeSingletonCreation(String beanName) 方法源码：

1：使用@Lazy 修饰。

2：这其实是一个操作不当造成的问题，因为spring的三级缓存已经解决了set注入导致的循环依赖，而这几个bean并不是全部都是使用构造器注入。

实验证明：

偏偏使用了会报错的一种组合......

springboot 异常： Requested bean is currently in creation: Is there an unresolvable circular reference?

2018-07-31 11:56:18.812  WARN 10316 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name ‘adminController‘: Unsatisfied dependency expressed through field ‘adminUserService‘; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name ‘adminUserService‘: Unsatisfied dependency expressed through field ‘baseMapper‘; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name ‘adminUserDao‘ defined in file [E:antdWorkspacepayadminv5	argetclassescompaycloudxdaoAdminUserDao.class]: Unsatisfied dependency expressed through bean property ‘sqlSessionFactory‘; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name ‘sqlSessionFactory‘ defined in class path resource [com/baomidou/mybatisplus/spring/boot/starter/MybatisPlusAutoConfiguration.class]: Unsatisfied dependency expressed through method ‘sqlSessionFactory‘ parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name ‘dataSource‘ defined in class path resource [com/paycloudx/datasources/DynamicDataSourceConfig.class]: Unsatisfied dependency expressed through method ‘dataSource‘ parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘firstDataSource‘ defined in class path resource [com/paycloudx/datasources/DynamicDataSourceConfig.class]: Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘org.springframework.boot.autoconfigure.jdbc.DataSourceInitializerInvoker‘: Invocation of init method failed; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name ‘dataSource‘: Requested bean is currently in creation: Is there an unresolvable circular reference?
2018-07-31 11:56:18.825  INFO 10316 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2018-07-31 11:56:18.834  WARN 10316 --- [ost-startStop-1] o.a.c.loader.WebappClassLoaderBase       : The web application [ROOT] appears to have started a thread named [Abandoned connection cleanup thread] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 java.lang.Object.wait(Native Method)
 java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
 com.mysql.cj.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:43)
2018-07-31 11:56:18.845  INFO 10316 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with ‘debug‘ enabled.
2018-07-31 11:56:18.847 ERROR 10316 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

The dependencies of some of the beans in the application context form a cycle:

   adminController (field private com.paycloudx.service.AdminUserService com.paycloudx.controller.AdminController.adminUserService)
      ↓
   adminUserService (field protected com.baomidou.mybatisplus.mapper.BaseMapper com.baomidou.mybatisplus.service.impl.ServiceImpl.baseMapper)
      ↓
   adminUserDao defined in file [E:antdWorkspacepayadminv5	argetclassescompaycloudxdaoAdminUserDao.class]
      ↓
   sqlSessionFactory defined in class path resource [com/baomidou/mybatisplus/spring/boot/starter/MybatisPlusAutoConfiguration.class]
┌─────┐
|  dataSource defined in class path resource [com/paycloudx/datasources/DynamicDataSourceConfig.class]
↑     ↓
|  firstDataSource defined in class path resource [com/paycloudx/datasources/DynamicDataSourceConfig.class]
↑     ↓
|  org.springframework.boot.autoconfigure.jdbc.DataSourceInitializerInvoker
└─────┘



Process finished with exit code 1

异常信息

 

项目框架：

springboot + Mybatis + Mybatis Plus 

配置了druid多数据源，刚搭建的时候启动正常，写好Controller，Service，Dao等代码后，启动报错。

百度不到对应的错了，问了公司大神，一下子就解决了，唉。

解决方案：

　　启动类注解：

    @SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})