升级spring-kafka-test至2.4.13.RELEASE时EmbeddedKafkaBroker报错

问题背景 #

之前使用spring-kafka-test 2.1.4.RELEASE搭配KafkaEmbedded组件，升级spring-kafka-test到2.4.13.RELEASE时，迁移至EmbeddedKafkaBroker并使用@EmbeddedKafka注解，出现如下错误：

java.lang.NoClassDefFoundError: org/springframework/core/log/LogAccessor 
  at org.springframework.kafka.test.EmbeddedKafkaBroker.<clinit>(EmbeddedKafkaBroker.java:92)
  at org.springframework.kafka.test.context.EmbeddedKafkaContextCustomizer.customizeContext(EmbeddedKafkaContextCustomizer.java:71)
  at org.springframework.boot.test.context.SpringBootContextLoader$ContextCustomizerAdapter.initialize(SpringBootContextLoader.java:336)
  at org.springframework.boot.SpringApplication.applyInitializers(SpringApplication.java:626)
  at org.springframework.boot.SpringApplication.prepareContext(SpringApplication.java:366)
  at org.springframework.boot.SpringApplication.run(SpringApplication.java:325)
  at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:138)
  at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99)
  at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:117)
  at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:107)
  at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:117)
  at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)
  at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:242)
  at org.springframework.test.context.testng.AbstractTestNGSpringContextTests.springTestContextPrepareTestInstance(AbstractTestNGSpringContextTests.java:145)
  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.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:85)
  at org.testng.internal.Invoker.invokeConfigurationMethod(Invoker.java:510)
  at org.testng.internal.Invoker.invokeConfigurations(Invoker.java:211)
  at org.testng.internal.Invoker.invokeConfigurations(Invoker.java:138)
  at org.testng.internal.TestMethodWorker.invokeBeforeClassMethods(TestMethodWorker.java:170)
  at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:104)
  at org.testng.TestRunner.privateRun(TestRunner.java:774)
  at org.testng.TestRunner.run(TestRunner.java:624)
  at org.testng.SuiteRunner.runTest(SuiteRunner.java:359)
  at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:354)
  at org.testng.SuiteRunner.privateRun(SuiteRunner.java:312)
  at org.testng.SuiteRunner.run(SuiteRunner.java:261)
  at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
  at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
  at org.testng.TestNG.runSuitesSequentially(TestNG.java:1215)
  at org.testng.TestNG.runSuitesLocally(TestNG.java:1140)
  at org.testng.TestNG.run(TestNG.java:1048)
  at com.intellij.rt.testng.IDEARemoteTestNG.run(IDEARemoteTestNG.java:66)
  at com.intellij.rt.testng.RemoteTestNGStarter.main(RemoteTestNGStarter.java:109)
 
Caused by: java.lang.ClassNotFoundException: org.springframework.core.log.LogAccessor
  at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
  at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
  at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
  at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
  37 more

当前环境：spring-boot-starter-parent 2.0.0.RELEASE，spring-kafka 2.1.4.RELEASE，已尝试过不同版本的spring-kafka-test。

错误原因 #

• org.springframework.core.log.LogAccessor是Spring Core 5.1及以上版本才新增的类，而spring-boot-starter-parent 2.0.0.RELEASE对应的Spring Core版本为5.0.x，版本不匹配导致找不到该类。
• spring-kafka与spring-kafka-test版本不一致（2.1.4 vs 2.4.13），进一步加剧了依赖兼容性问题。

解决方案 #

方案一：统一升级Spring Boot与Kafka相关依赖（推荐） #

将Spring Boot版本升级至与spring-kafka-test 2.4.13.RELEASE兼容的版本，同时同步升级spring-kafka版本，保证依赖版本一致：

1. 修改pom.xml中的父依赖版本为2.2.x（spring-kafka 2.4.x对应Spring Boot 2.2.x官方适配）：

   <parent>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-parent</artifactId>
       <version>2.2.13.RELEASE</version>
       <relativePath/> <!-- lookup parent from repository -->
   </parent>
   

2. 同步调整spring-kafka与spring-kafka-test版本一致：

   <dependency>
       <groupId>org.springframework.kafka</groupId>
       <artifactId>spring-kafka</artifactId>
       <version>2.4.13.RELEASE</version>
   </dependency>
   <dependency>
       <groupId>org.springframework.kafka</groupId>
       <artifactId>spring-kafka-test</artifactId>
       <version>2.4.13.RELEASE</version>
       <scope>test</scope>
   </dependency>
   

3. 验证@EmbeddedKafka与EmbeddedKafkaBroker的使用，此时Spring Core版本已升级至5.2.x，包含LogAccessor类，可解决错误。

方案二：降低spring-kafka-test版本适配现有Spring Boot #

如果无法升级Spring Boot，需将spring-kafka-test版本降至与spring-boot-starter-parent 2.0.0.RELEASE及spring-kafka 2.1.4.RELEASE兼容的2.1.x系列，但此版本仍使用KafkaEmbedded而非EmbeddedKafkaBroker：

<dependency>
    <groupId>org.springframework.kafka</groupId>
    <artifactId>spring-kafka-test</artifactId>
    <version>2.1.4.RELEASE</version>
    <scope>test</scope>
</dependency>

注意：此方案无法使用EmbeddedKafkaBroker，若必须使用该组件，只能选择方案一升级Spring Boot。

内容的提问来源于stack exchange，提问作者Charles Antony Raja