Maven工程分模組開發完成

父工程配置了 tomcat7外掛，執行 run命令

執行run指令時失敗，報錯資訊如下：

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

分析報錯原因：

[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 檔案中，指定了重複了子模組 maven_dao

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

解決：

• 直接將重複的部分刪除即可正常執行Maven命令