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前言
我们做项目迁移时候，不免会遇到各种各样的问题，特别是不同库、同文件名、同表之类，会导致连启动都会失败，那么今天我们来一探究竟其中一个常见问题
问题
2022-05-25 09:40:04,044 INFO DruidDataSource:930 - {dataSource-2} inited
2022-05-25 09:40:13,398 INFO DruidDataSource:930 - {dataSource-3} inited
2022-05-25 09:40:15,374 WARN AnnotationConfigEmbeddedWebApplicationContext:550 - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'productController': Unsatisfied dependency expressed through field 'projectService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'appProjectServiceImpl': Unsatisfied dependency expressed through field 'proRelationService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'proRelationServiceImpl': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named 'projectMapper' is expected to be of type 'com.mapper.AppProjectMapper' but was actually of type 'com.sun.proxy.$Proxy160'
2022-05-25 09:40:15,377 INFO DruidDataSource:1825 - {dataSource-3} closed
2022-05-25 09:40:15,379 INFO DruidDataSource:1825 - {dataSource-2} closed
2022-05-25 09:40:15,379 WARN CommonAnnotationBeanPostProcessor:162 - Invocation of destroy method failed on bean with name 'scheduledTask': java.lang.NullPointerException
2022-05-25 09:40:15,387 INFO DruidDataSource:1825 - {dataSource-1} closed
2022-05-25 09:40:15,387 INFO AnnotationConfigApplicationContext:987 - Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@53b43413: startup date [Wed May 25 09:39:44 CST 2022]; parent: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@12bbf8b1
2022-05-25 09:40:15,395 INFO AutoConfigurationReportLoggingInitializer:101 -
***************************
APPLICATION FAILED TO START
***************************
Description:
The bean 'projectMapper' could not be injected as a 'com.system.mapper.AppProjectMapper' because it is a JDK dynamic proxy that implements:
com.test.system.core.Mapper
Action:
Consider injecting the bean as one of its interfaces or forcing the use of CGLib-based proxies by setting proxyTargetClass=true on @EnableAsync and/or @EnableCaching.
上面包名不用注意，已经被我删除修改过。
发现
从上可以看得出，我们一个projectMapper报错，因为主要配置基于JDK的代理还是基于类的动态代理的配置，这种错误提示需要设置基于类的代理才行。
解决
1、网上常见办法
过proxy-target-class=true或者transactional
2、修改命名
private AppProjectMapper projectMapper;
private ProjectMapper projectMapper;
在两个类类似情况下,假如你命名一样的话，jdk会默认去找下面那个类，最终发现找不到对应方法，也就报错了
你可以看上面报错信息
你现在应该知道了吧，该问题在哪个类，还能定义到那个bean出现问题。
后言
因为jdk动态代理对类进行包装后，原生类隐藏了（->target），冒出来一个只代表接口实现的新生类；即接口申明的方法，新生类才会有。 如果你执意要以此新生类注入至其他bean实例，那么在runtime过程中，可能因为你调用的方法未在接口中声明而抛出异常；
遇到问题不要慌，慢慢来肯定会发现问题所在。我是人见人爱的爱玩基金的秀总，如果你觉得对你有帮助，请点个赞吧
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后语
如果本文对你哪怕有一丁点帮助，请帮忙点好看。你的好看是我坚持写作的动力。 另外，关注免费学习。
The bean 'projectMapper' could not be injected as a 'com.vivo.qa.test.system.pqm.mapper.AppProjectMapper' because it is a JDK dynamic proxy that implements: com.vivo.qa.test.system.core.Mapper
