maven编译问题之 -The POM for XXX is invalid, transitive dependencies (if any) will not be available

问题一： 把父工程tao-parent install 到maven本地仓后，接着install tao-common工程，然后报错

报错信息如下：

[WARNING] The POM for com.fasterxml.jackson.core:jackson-databind:jar:2.4.2 is invalid, transitive dependencies (if any) will not be available，enable debug logging for more details

错误信息意思是 com.fasterxml.jackson.core:jackson-databind:jar:2.4.2 这个jar包的POM文件无效，依赖传递不可用；

解决办法：在install 时，使用调试模式， install -X ，将控制台的信息拷贝出来，查找[WARNING]信息，可以看到如下错误提示：

[WARNING] The POM for com.fasterxml.jackson.core:jackson-databind:jar:2.4.2 is invalid, transitive dependencies (if any) will not be available: 1 problem was encountered while building the effective model for com.fasterxml.jackson.core:jackson-databind:2.4.2

[FATAL] Non-parseable POM D:\apache-maven-3.5.2\Maven\com\fasterxml\jackson\jackson-parent\2.4\jackson-parent-2.4.pom: processing instruction can not have PITarget with reserved xml name (position: END_TAG seen ...</build>\n\n</project>\n<?xml ... @180:7)  @ D:\apache-maven-3.5.2\Maven\com\fasterxml\jackson\jackson-parent\2.4\jackson-parent-2.4.pom, line 180, column 7

提示信息指向了 D:\apache-maven-3.5.2\Maven\com\fasterxml\jackson\jackson-parent\2.4\目录下的  jackson-parent-2.4.pom文件

找到该POM文件 180行，看到有提示信息，将jackson-parent\2.4目录下的所有文件删除，然后重新使用install命令把tao-common打包到本地maven仓正常，正常仓库下的文件如下，这个 jackson-parent-2.4.pom文件和之前的 jackson-parent-2.4.pom文件的内容也不相同 ！

问题二：上面问题解决后，install tao-manager时，报如下告警信息：

[WARNING] The POM for org.mybatis:mybatis-spring:jar:1.2.2 is invalid, transitive dependencies (if any) will not be available, enable debug logging for more details

[WARNING] The POM for commons-logging:commons-logging:jar:1.2 is invalid, transitive dependencies (if any) will not be available, enable debug logging for more details

选中项目，右键->run as ，选择maven build ...，然后在对话框中的Goals项填入" dependency:tree",再在"debug output"打上勾，并将此项启动的名字改为"showDependency-tree",然后点击Run按钮， 获取maven依赖关系，执行后，将控制台的调试信息拷贝出来，查找FATAL级别的，如下：

[WARNING] The POM for org.mybatis:mybatis-spring:jar:1.2.2 is invalid, transitive dependencies (if any) will not be available: 1 problem was encountered while building the effective model for org.mybatis:mybatis-spring:1.2.2
[FATAL] Non-parseable POM D:\apache-maven-3.5.2\Maven\org\mybatis\mybatis-parent\20\mybatis-parent-20.pom: only whitespace content allowed before start tag and not o (position: START_DOCUMENT seen o... @1:1) @ D:\apache-maven-3.5.2\Maven\org\mybatis\mybatis-parent\20\mybatis-parent-20.pom, line 1, column 1

[WARNING] The POM for commons-logging:commons-logging:jar:1.2 is invalid, transitive dependencies (if any) will not be available: 1 problem was encountered while building the effective model for commons-logging:commons-logging:1.2

[FATAL] Non-parseable POM D:\apache-maven-3.5.2\Maven\org\apache\commons\commons-parent\34\commons-parent-34.pom: start tag not allowed in epilog but got p (position: END_TAG seen ...</properties>\r\n\r\n</project>\r\n              <p... @1387:17)  @ D:\apache-maven-3.5.2\Maven\org\apache\commons\commons-parent\34\commons-parent-34.pom, line 1387, column 17

[WARNING] The POM for commons-logging:commons-logging:jar:1.2 is invalid, transitive dependencies (if any) will not be available: 1 problem was encountered while building the effective model for commons-logging:commons-logging:1.2

[FATAL] Non-parseable POM D:\apache-maven-3.5.2\Maven\org\apache\commons\commons-parent\34\commons-parent-34.pom: start tag not allowed in epilog but got p (position: END_TAG seen ...</properties>\r\n\r\n</project>\r\n              <p... @1387:17)  @ D:\apache-maven-3.5.2\Maven\org\apache\commons\commons-parent\34\commons-parent-34.pom, line 1387, column 17

可以得知D:\apache-maven-3.5.2\Maven\org\apache\commons\commons-parent\34\路径下的 commons-parent-34.pom文件

和D:\apache-maven-3.5.2\Maven\org\mybatis\mybatis-parent\20路径下的  mybatis-parent-20.pom文件损坏。删除后更新maven仓库，然后install正常

经验提升：

1.maven编译问题，有可能是某些需要的文件坏了，删除后右键单击工程名==》maven ==》 update project ， 更新 一下maven仓就解决了

2.遇到maven编译问题，可以使用maven调试模式，获取更精确的问题信息，从而快速定位问题  具体步骤是： 右键单击工程名==》run as ==》maven build...(选择带...的这个)，

在Goals后面输入clean install -X ，之所以加上clean命令，是为了清除之前打到本地仓的包

3. 如何查lib下的jar来自哪个maven依赖（用于解决jar版本冲突，第三方依赖jar包pom文件损坏问题)：

选中项目，右键->run as ，选择maven build ...，然后在对话框中的Goals项填入" dependency:tree",再在"debug output"打上勾，并将此项启动的名字改为"showDependency-tree",然后点击“Debug"/Run按钮， console里面会很详细地显示每个pom里面配置的依赖它们会带来哪些jar文件，以及jar包，pom错误信息

参考资料：

https://www.cnblogs.com/woshicckk/p/6410477.html

https://blog.csdn.net/rocklee/article/details/51691617