解压重打包Spring Boot FatJar后启动失败：请求映射冲突

环境信息 #

• Ubuntu 15.8
• Spring Boot版本：2.7.14

操作步骤 #

1. 解压Spring Boot FatJar：

jar -xf a.jar 

2. 重新打包：

jar cf0M a.jar BOOT-INF META-INF org

3. 启动应用：

java -jar a.jar

报错信息 #

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'requestMappingHandlerMapping' defined in class path resource [org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: Ambiguous mapping. Cannot map 'codegenTableController' method 
cn.luo.yudao.module.infra.controller.admin.codegen.CodegenTableController#listByIds(Collection)
to {GET [/admin-api/infra/codegenTable]}: There is already 'codegenTableController' bean method
cn.luo.yudao.module.infra.controller.admin.codegen.CodegenTableController#exportExcel(Object, HttpServletResponse) mapped.
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1804)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:620)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542)
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:955)
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:921)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583)
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147)
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:731)
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:408)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:307)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1303)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1292)
        at cn.luo.yudao.ServerApplication.main(ServerApplication.java:27)
        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:65)
Caused by: java.lang.IllegalStateException: Ambiguous mapping. Cannot map 'codegenTableController' method 
cn.luo.yudao.module.infra.controller.admin.codegen.CodegenTableController#listByIds(Collection)
to {GET [/admin-api/infra/codegenTable]}: There is already 'codegenTableController' bean method
cn.luo.yudao.module.infra.controller.admin.codegen.CodegenTableController#exportExcel(Object, HttpServletResponse) mapped.
        at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping$MappingRegistry.validateMethodMapping(AbstractHandlerMethodMapping.java:669)
        at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping$MappingRegistry.register(AbstractHandlerMethodMapping.java:635)
        at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.registerHandlerMethod(AbstractHandlerMethodMapping.java:332)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping.registerHandlerMethod(RequestMappingHandlerMapping.java:420)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping.registerHandlerMethod(RequestMappingHandlerMapping.java:76)
        at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.lambda$detectHandlerMethods$2(AbstractHandlerMethodMapping.java:299)
        at java.util.LinkedHashMap.forEach(LinkedHashMap.java:684)
        at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.detectHandlerMethods(AbstractHandlerMethodMapping.java:297)
        at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.processCandidateBean(AbstractHandlerMethodMapping.java:266)
        at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.initHandlerMethods(AbstractHandlerMethodMapping.java:225)
        at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.afterPropertiesSet(AbstractHandlerMethodMapping.java:213)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping.afterPropertiesSet(RequestMappingHandlerMapping.java:205)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1863)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1800)
        ... 24 common frames omitted

问题补充 #

确认类路径下无同名类，原FatJar可正常启动。此前在RedHat环境对其他FatJar执行相同操作可正常运行，但Ubuntu环境下出现此问题，Windows 11笔记本上执行相同操作却能正常启动，怀疑是类路径相关问题。

排查与解决方案 #

1. 调整打包目录顺序
   Ubuntu下的jar命令对目录顺序敏感，当前打包命令将BOOT-INF放在最前，可能导致Spring Boot加载时重复扫描Controller类。修改打包命令，把META-INF放在首位：

jar cf0M a.jar META-INF BOOT-INF org

META-INF中的MANIFEST.MF是Spring Boot启动的核心配置，优先打包它能保证类加载顺序正确。

2. 检查解压目录是否存在重复类
   执行以下命令查找是否有重复的CodegenTableController.class文件：

find ./a -name "CodegenTableController.class"

若发现多个结果，说明解压或打包过程中引入了重复类，删除多余文件后重新打包。

3. 使用Spring Boot官方工具修改Jar
   手动解压再打包容易破坏FatJar的内部结构，推荐使用spring-boot-loader-tools来修改Jar：

• 在pom.xml中添加依赖：

  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-loader-tools</artifactId>
      <version>2.7.14</version>
      <scope>provided</scope>
  </dependency>
  

• 通过工具类操作Jar，避免手动操作带来的结构问题。

4. 对齐JDK版本
   检查Ubuntu环境的JDK版本是否与RedHat、Windows一致：

java -version

不同JDK版本对类加载的逻辑可能存在差异，切换到与原环境相同的JDK版本后重试启动。

内容的提问来源于stack exchange，提问作者ki Lo