Maven分模块开发执行指令失败的问题

Maven工程分模块开发完成 父工程配置了 tomcat7插件，运行 run命令

执行run指令时失败，报错信息如下：

D:\java\JDK8\bin\java.exe "-Dmaven.multiModuleProjectDirectory=D:\Idea2020\IntelliJ IDEA 2020.1\MavenProject_parent" -Dmaven.home=D:\apache-maven-3.6.3
-Dclassworlds.conf=D:\apache-maven-3.6.3\bin\m2.conf "
-Dmaven.ext.class.path=D:\Idea2020\IntelliJ IDEA 2020.1\plugins\maven\lib\maven-event-listener.jar" "
-javaagent:D:\Idea2020\IntelliJ IDEA 2020.1\lib\idea_rt.jar=50388:D:\Idea2020\IntelliJ IDEA 2020.1\bin"
-Dfile.encoding=UTF-8 -classpath D:\apache-maven-3.6.3\boot\plexus
-classworlds-2.6.0.jar;D:\apache-maven-3.6.3\boot\plexus
-classworlds.license org.codehaus.classworlds.Launcher
-Didea.version2020.1 -s D:\apache-maven-3.6.3\conf\settings.xml
-Dmaven.repo.local=D:\apache-maven-3.6.3\my_maven_local_repository install
[INFO] Scanning for projects...
[ERROR] [ERROR] Some problems were encountered while processing the POMs:
[ERROR] 'modules.module[3]' specifies duplicate child module maven_dao @ line 29, column 17
 @
[ERROR] The build could not read 1 project -> [Help 1]
[ERROR]  
[ERROR]   The project com.idea.maven:MavenProject_parent:1.0-SNAPSHOT (D:\Idea2020\IntelliJ IDEA 2020.1\MavenProject_parent\pom.xml) has 1 error
[ERROR]     'modules.module[3]' specifies duplicate child module maven_dao @ line 29, column 17
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/ProjectBuildingException

分析报错原因：

[ERROR] [ERROR] Some problems were encountered while processing the POMs:
[ERROR] 'modules.module[3]' specifies duplicate child module maven_dao @ line 29, column 17

原因： 在父工程的Pom.xml 文件中，指定了重复了子模块 maven_dao

<modules>
  <module>maven_dao</module>
  <module>maven_service</module>
  <module>maven_web</module>
  <module>maven_dao</module>
 </modules>
 <packaging>pom</packaging>

解决： 直接将重复的部分删除即可正常运行Maven命令

总结