新年上班，开始新的搬砖之旅。这天需要将一个系统从Springboot 1.6.5升级到2.1.x版本，于是照着网上的一些教程改了一些配置，修改了一些类，然后点击Run，结果一顿操作猛如虎，一Run就GG～～

🙋 问题现场

直接上异常：

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'abcApiService' defined in class path resource [com/xxx/ag/backend/BackendBizBeanConfiguration.class]: Unexpected exception during bean creation; nested exception is java.lang.reflect.UndeclaredThrowableException
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:529)
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:207)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.resolveBeanByName(AbstractAutowireCapableBeanFactory.java:453)
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.autowireResource(CommonAnnotationBeanPostProcessor.java:527)
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.getResource(CommonAnnotationBeanPostProcessor.java:497)
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor$ResourceElement.getResourceToInject(CommonAnnotationBeanPostProcessor.java:650)
	at org.springframework.beans.factory.annotation.InjectionMetadata$InjectedElement.inject(InjectionMetadata.java:228)
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:119)
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessProperties(CommonAnnotationBeanPostProcessor.java:318)
	... 17 common frames omitted
Caused by: java.lang.reflect.UndeclaredThrowableException: null
	at com.sun.proxy.$Proxy145.hashCode(Unknown Source)
	at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:936)
	at java.util.concurrent.ConcurrentHashMap.containsKey(ConcurrentHashMap.java:964)
	at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.requiresDestruction(PersistenceAnnotationBeanPostProcessor.java:392)
	at org.springframework.beans.factory.support.DisposableBeanAdapter.hasApplicableProcessors(DisposableBeanAdapter.java:405)
	at org.springframework.beans.factory.support.AbstractBeanFactory.requiresDestruction(AbstractBeanFactory.java:1856)
	at org.springframework.beans.factory.support.AbstractBeanFactory.registerDisposableBeanIfNecessary(AbstractBeanFactory.java:1873)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:635)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516)
	... 28 common frames omitted
Caused by: java.util.concurrent.ExecutionException: com.xxx.ag.nrpc.client.NrpcInvocationException: MethodInfo not found
	at com.google.common.util.concurrent.AbstractFuture.getDoneValue(AbstractFuture.java:503)
	at com.google.common.util.concurrent.AbstractFuture.get(AbstractFuture.java:404)
	at com.google.common.util.concurrent.AbstractFuture$TrustedFuture.get(AbstractFuture.java:86)
	at com.xxx.ag.nrpc.client.NrpcClient.invokeMethod(NrpcClient.java:129)
	at com.xxx.ag.nrpc.spring.NrpcInvocationHandler.invoke(NrpcInvocationHandler.java:53)
	... 37 common frames omitted
Caused by: com.xxx.ag.nrpc.client.NrpcInvocationException: MethodInfo not found
	at com.xxx.ag.nrpc.client.NrpcClient.lambda$internalInvoke$2(NrpcClient.java:195)
	at com.google.common.util.concurrent.AbstractTransformFuture$TransformFuture.doTransform(AbstractTransformFuture.java:239)
	at com.google.common.util.concurrent.AbstractTransformFuture$TransformFuture.doTransform(AbstractTransformFuture.java:229)
	at com.google.common.util.concurrent.AbstractTransformFuture.run(AbstractTransformFuture.java:130)
	at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:399)
	at com.google.common.util.concurrent.AbstractFuture.executeListener(AbstractFuture.java:911)
	at com.google.common.util.concurrent.AbstractFuture.complete(AbstractFuture.java:822)
	at com.google.common.util.concurrent.AbstractFuture.set(AbstractFuture.java:664)
	at io.grpc.stub.ClientCalls$GrpcFuture.set(ClientCalls.java:446)
	at io.grpc.stub.ClientCalls$UnaryStreamToFuture.onClose(ClientCalls.java:425)
	at io.grpc.internal.ClientCallImpl.closeObserver(ClientCallImpl.java:419)
	at io.grpc.internal.ClientCallImpl.access$100(ClientCallImpl.java:60)
	at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl.close(ClientCallImpl.java:493)
	at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl.access$500(ClientCallImpl.java:422)
	at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInContext(ClientCallImpl.java:525)
	at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
	at io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:102)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:748)

啥情况，为啥应用启动后立即就调用远程接口的方法？而且还是没有注册的方法，所以才导致Bean创建失败。异常堆栈中没有显示出具体调用的远程方法，那就DEBUG一下看看，将断点打在RPC框架客户端的invoke方法上：

执行到断点，可以看到，是Spring JPA中的代码在初始化时调用了远程接口的hashcode方法，而这种Object方法在远程的服务中是不会注册的，所以就会导致客户端调用失败，进而引起客户端的Bean创建失败。

🛠️ 解决方案

出现上面问题的原因很简单，就是JPA在初始化bean的时候，把远程服务接口也初始化了，但是这个服务接口是一个动态代理类，调用它的方法就会直接通过RPC框架调用远程方法，进而导致连锁失败。

解决的方法很简单，既然JPA会初始化远程服务接口，那就不让他这么做就行了。

1. 首先重写bean的加载顺序，创建一个新类。当一个bean是代理类且是接口时，就直接不进行初始化。

/**
 * @author xxx
 */
public class RpcPersistenceAnnotationBeanPostProcessor extends PersistenceAnnotationBeanPostProcessor {
    @Override
    public boolean requiresDestruction(Object bean) {
        Class<?> clazz = bean.getClass();
        //是代理接口类
        if (Proxy.isProxyClass(clazz) && clazz.getInterfaces().length == 1) {
            return false;
        }
        return super.requiresDestruction(bean);
    }
}

2. 第二步,将RpcPersistenceAnnotationBeanPostProcessor类设置为默认的PersistenceAnnotationBeanPostProcessor bean，并且将bean的名称也设置成Spring中默认实现类的名称，进行覆盖

    @Bean(AnnotationConfigUtils.PERSISTENCE_ANNOTATION_PROCESSOR_BEAN_NAME)
    @Primary
    public PersistenceAnnotationBeanPostProcessor persistenceAnnotationBeanPostProcessor(){
        return new RpcPersistenceAnnotationBeanPostProcessor();
    }

3. 第三步，重写BeanPostProcessor，如果发现spring容器开始初始化默认的PersistenceAnnotationBeanPostProcessor ，那就把我们上面自定义的bean先初始化，从而达到优先初始化的目的

@Component
public class RpcBeanPostProcessor extends InstantiationAwareBeanPostProcessorAdapter implements BeanFactoryAware {
    private ConfigurableListableBeanFactory beanFactory;

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        if (!(beanFactory instanceof ConfigurableListableBeanFactory)) {
            throw new IllegalArgumentException("AutowiredAnnotationBeanPostProcessor requires a ConfigurableListableBeanFactory: " + beanFactory);
        }
        this.beanFactory = (ConfigurableListableBeanFactory) beanFactory;
    }

    @Override
    public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException {
        if (AnnotationConfigUtils.PERSISTENCE_ANNOTATION_PROCESSOR_BEAN_NAME.equals(beanName)) {
            beanFactory.getBean(RpcPersistenceAnnotationBeanPostProcessor.class);
        }
        return null;
    }

    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        return super.postProcessBeforeInitialization(bean, beanName);
    }
}

4. 最后，还需要在配置文件增加一个配置,即允许覆盖相同名称的bean

spring.main.allow-bean-definition-overriding=true

OK，到这里就修改完成了，把应用Run起来，顺利启动。

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