springboot升级： Failed to initialize DiscoveryClient

目标版本

<spring.boot.version>2.5.15</spring.boot.version>

<spring-framework.version>5.3.39</spring-framework.version>

<spring-cloud.version>2020.0.6</spring-cloud.version>                

这应该是在jdk8下 的最大能力了，再升级就要升级到jdk17了

问题

贴一段报错

 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'scopedTarget.eurekaClient' defined in class path resource [org/springframework/cloud/netflix/eureka/EurekaClientAutoConfiguration$RefreshableEurekaClientConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.netflix.discovery.EurekaClient]: Factory method 'eurekaClient' threw exception; nested exception is java.lang.RuntimeException: Failed to initialize DiscoveryClient!
   at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:646)
   at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:626)
   at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352)
   at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195)
   at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582)
   at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542)
   at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$1(AbstractBeanFactory.java:375)
   at org.springframework.cloud.context.scope.GenericScope$BeanLifecycleWrapper.getBean(GenericScope.java:376)
   at org.springframework.cloud.context.scope.GenericScope.get(GenericScope.java:179)
   at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:372)
   at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:209)
   at org.springframework.aop.target.SimpleBeanTargetSource.getTarget(SimpleBeanTargetSource.java:35)
   at org.springframework.cloud.netflix.eureka.serviceregistry.EurekaRegistration.getTargetObject(EurekaRegistration.java:127)
   at org.springframework.cloud.netflix.eureka.serviceregistry.EurekaRegistration.getEurekaClient(EurekaRegistration.java:115)
   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:498)
   at org.springframework.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:282)
   at org.springframework.cloud.context.scope.GenericScope$LockedScopedProxyFactoryBean.invoke(GenericScope.java:485)
   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
   at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:762)
   at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:707)
   at org.springframework.cloud.netflix.eureka.serviceregistry.EurekaRegistration$$EnhancerBySpringCGLIB$$c2ad3cf.getEurekaClient(<generated>)
   at org.springframework.cloud.netflix.eureka.serviceregistry.EurekaServiceRegistry.maybeInitializeClient(EurekaServiceRegistry.java:54)
   at org.springframework.cloud.netflix.eureka.serviceregistry.EurekaServiceRegistry.register(EurekaServiceRegistry.java:38)
   at org.springframework.cloud.netflix.eureka.serviceregistry.EurekaAutoServiceRegistration.start(EurekaAutoServiceRegistration.java:83)
   at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:183)
   at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:58)
   at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:365)
   at java.lang.Iterable.forEach(Iterable.java:75)
   at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:160)
   at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:128)
   at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:949)
   at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:594)
   at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145)
   at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:780)
   at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:453)
   at org.springframework.boot.SpringApplication.run(SpringApplication.java:343)
   at org.springframework.boot.SpringApplication.run(SpringApplication.java:1370)
   at org.springframework.boot.SpringApplication.run(SpringApplication.java:1359)
   at com.******.SystemAdminApplication.main(SystemAdminApplication.java:24)
   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:498)
   at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:49)
   at org.springframework.boot.loader.Launcher.launch(Launcher.java:108)
   at org.springframework.boot.loader.Launcher.launch(Launcher.java:58)
   at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:88)
 Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.netflix.discovery.EurekaClient]: Factory method 'eurekaClient' threw exception; nested exception is java.lang.RuntimeException: Failed to initialize DiscoveryClient!
   at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)
   at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:641)
   ... 49 common frames omitted
 Caused by: java.lang.RuntimeException: Failed to initialize DiscoveryClient!
   at com.netflix.discovery.DiscoveryClient.<init>(DiscoveryClient.java:436)
   at com.netflix.discovery.DiscoveryClient.<init>(DiscoveryClient.java:283)
   at com.netflix.discovery.DiscoveryClient.<init>(DiscoveryClient.java:279)
   at org.springframework.cloud.netflix.eureka.CloudEurekaClient.<init>(CloudEurekaClient.java:66)
   at org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration$RefreshableEurekaClientConfiguration.eurekaClient(EurekaClientAutoConfiguration.java:295)
   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:498)
   at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
   ... 50 common frames omitted
 Caused by: java.lang.NoClassDefFoundError: com/sun/jersey/client/apache4/ApacheHttpClient4
   at com.netflix.discovery.shared.transport.jersey.Jersey1TransportClientFactories.newTransportClientFactory(Jersey1TransportClientFactories.java:59)
   at com.netflix.discovery.DiscoveryClient.scheduleServerEndpointTask(DiscoveryClient.java:528)
   at com.netflix.discovery.DiscoveryClient.<init>(DiscoveryClient.java:423)
   ... 59 common frames omitted
 Caused by: java.lang.ClassNotFoundException: com.sun.jersey.client.apache4.ApacheHttpClient4
   at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
   at org.springframework.boot.loader.LaunchedURLClassLoader.loadClass(LaunchedURLClassLoader.java:151)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
   ... 62 common frames omitted
 2025-03-18 16:58:09 --- [main] WARN  org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.context.ApplicationContextException: Failed to start bean 'eurekaAutoServiceRegistration'; nested exception is java.lang.NullPointerException
 2025-03-18 16:58:09 --- [main] INFO  com.alibaba.druid.pool.DruidDataSource - {dataSource-1} closing ...
 2025-03-18 16:58:09 --- [main] INFO  com.alibaba.druid.pool.DruidDataSource - {dataSource-1} closed
 2025-03-18 16:58:09 --- [main] INFO  org.apache.catalina.core.StandardService - Stopping service [Tomcat]
 2025-03-18 16:58:09 --- [main] ERROR org.springframework.boot.SpringApplication - Application run failed
 org.springframework.context.ApplicationContextException: Failed to start bean 'eurekaAutoServiceRegistration'; nested exception is java.lang.NullPointerException
   at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:186)
   at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:58)
   at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:365)
   at java.lang.Iterable.forEach(Iterable.java:75)
   at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:160)
   at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:128)
   at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:949)
   at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:594)
   at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145)
   at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:780)
   at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:453)
   at org.springframework.boot.SpringApplication.run(SpringApplication.java:343)
   at org.springframework.boot.SpringApplication.run(SpringApplication.java:1370)
   at org.springframework.boot.SpringApplication.run(SpringApplication.java:1359)
   at com.*****.SystemAdminApplication.main(SystemAdminApplication.java:24)
   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:498)
   at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:49)
   at org.springframework.boot.loader.Launcher.launch(Launcher.java:108)
   at org.springframework.boot.loader.Launcher.launch(Launcher.java:58)
   at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:88)
 Caused by: java.lang.NullPointerException: null
   at org.springframework.cloud.netflix.eureka.serviceregistry.EurekaServiceRegistry.maybeInitializeClient(EurekaServiceRegistry.java:54)
   at org.springframework.cloud.netflix.eureka.serviceregistry.EurekaServiceRegistry.register(EurekaServiceRegistry.java:38)
   at org.springframework.cloud.netflix.eureka.serviceregistry.EurekaAutoServiceRegistration.start(EurekaAutoServiceRegistration.java:83)
   at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:183)
   ... 22 common frames omitted
 

追踪

通过标注黄色的报错，我们知道 报错是由于 scopedTarget.eurekaClient' 这个bean无法创建引起的

而这个 scopedTarget.eurekaClient'   是由于  DiscoveryClient  无法初始化导致的

 DiscoveryClient  无法初始化是由于 java.lang.NoClassDefFoundError: com/sun/jersey/client/apache4/ApacheHttpClient4  没有这个类导致的

那么我们只需要解决这个类的问题就好了

这类的maven坐标如下

<dependency>
    <groupId>com.sun.jersey.contribs</groupId>
    <artifactId>jersey-apache-client4</artifactId>
</dependency>

一般 NoClassDefFoundError  这种报错一般由于以下原因导致

1、没有引入

一般直接引入对应的版本即可

2、引入多个版本导致冲突

通过统一版本解决，如果是间接引入可以在直接引入的包下面排除掉这个依赖

  <dependency>
    <groupId>com.example.group</groupId>
    <artifactId>dependency-A</artifactId>
    <version>1.0.0</version>   
    <exclusions>
      <exclusion>
        <groupId>com.example.group</groupId>
        <artifactId>dependency-C</artifactId>
      </exclusion>
    </exclusions>
  </dependency>

tips: 提供一个命令 帮助 查看依赖树 

mvn dependency:tree

解决

具体到升级spring boot这个问题

Spring Cloud 2020.0.x（Ilford）与 Jersey 的兼容性
在 Spring Cloud 2020.0.x 版本中，Eureka 客户端默认已弃用 Jersey 1.x，并改为使用 Spring 的 WebClient（基于 Reactor Netty）。

所以我们需要手动引入

<dependency>
    <groupId>com.sun.jersey.contribs</groupId>
    <artifactId>jersey-apache-client4</artifactId>
    <version>1.19.4</version>
</dependency>