问题：
执行mvn clean packege 时总有一个包打包不过去，说找不主类，错误如下：
[ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:2.1.4.RELEASE:repackage (repackage) on project loan-common: Execution repackage of goal org.springframework.boot:spring-boot-maven-plugin:2.1.4.RELEASE:repackage failed: Unable to find main class -> [Help 1] org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:2.1.4.RELEASE:repackage (repackage) on project my-common: Execution repackage of goal org.springframework.boot:spring-boot-maven-plugin:2.1.4.RELEASE:repackage failed: Unable to find main class at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:215) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81) at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56) at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128) at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305) at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192) at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105) at org.apache.maven.cli.MavenCli.execute (MavenCli.java:956) at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:288) at org.apache.maven.cli.MavenCli.main (MavenCli.java:192) 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:483) at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282) at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225) at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406) at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347) Caused by: org.apache.maven.plugin.PluginExecutionException: Execution repackage of goal org.springframework.boot:spring-boot-maven-plugin:2.1.4.RELEASE:repackage failed: Unable to find main class at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:148)
查找原因
最终检查所有模块配置，发现总pom.xml文件中有打包插件。
而该插件只能在需要启动的web模块，最终启动的（jar或者war包的）pom文件中，其他模块是不需要的，总pom中也不需要。
否则会导致打包的时候报错。
解决方案：
删掉除web模块下，其他所有pom文件中的打包插件，整理清楚依赖关系。
1、只有总pom文件 打包为：<packaging>pom</packaging>
主要配置为：
<modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.4.RELEASE</version> <relativePath/> </parent> <groupId>com.ylj.student</groupId> <artifactId>myproject</artifactId> <version>1.0-SNAPSHOT</version> <packaging>pom</packaging> <name>myproject</name> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <modules> <module>my-web</module> <module>my-service</module> <module>my-dao</module> <module>my-common</module> </modules> <dependencyManagement> <dependencies> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.18.8</version> </dependency> </dependencies> </dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> <version>2.1.4.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <version>2.1.4.RELEASE</version> <scope>test</scope> </dependency> </dependencies>2、其他子模块pom文件 打包为: <packaging>jar</packaging>
<modelVersion>4.0.0</modelVersion> <parent> <groupId>com.ylj.student</groupId> <artifactId>myproject</artifactId> <version>1.0-SNAPSHOT</version> </parent> <artifactId>my-common</artifactId> <packaging>jar</packaging> <name>my-common</name> <dependencies> <dependency> <groupId>com.ylj.student</groupId> <artifactId>my-dao</artifactId> <version>1.0-SNAPSHOT</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> </dependency> </dependencies>3、web模块pom文件 打包为: <packaging>jar</packaging>，同时添加maven 插件。
<modelVersion>4.0.0</modelVersion> <parent> <groupId>om.ylj.student</groupId> <artifactId>myproject</artifactId> <version>1.0-SNAPSHOT</version> </parent> <artifactId>my-web</artifactId> <name>my-web</name> <packaging>jar</packaging> <dependencies> <dependency> <groupId>com.ylj.student</groupId> <artifactId>my-common</artifactId> <version>1.0-SNAPSHOT</version> </dependency> <dependency> <groupId>om.ylj.student</groupId> <artifactId>my-service</artifactId> <version>1.0-SNAPSHOT</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build>
