Maven打包错误：Failed to execute goal on project client: Could not resolve dependencies for project

我先说下我的打包步骤

一、复现

我的应用中有两个模块：client和common
其中client依赖common

打包步骤

先打包common，build success
再打包client，此时出错！错误信息如下

[INFO] Scanning for projects...
[INFO] 
[INFO] -------------------------< org.example:client >-------------------------
[INFO] Building client 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  0.309 s
[INFO] Finished at: 2020-06-17T16:58:00+08:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal on project client: Could not resolve dependencies for project org.example:client:jar:1.0-SNAPSHOT: Failed to collect dependencies at org.example:common:jar:1.0-SNAPSHOT: Failed to read artifact descriptor for org.example:common:jar:1.0-SNAPSHOT: Could not find artifact org.example:project-test:pom:1.0-SNAPSHOT -> [Help 1]
[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/DependencyResolutionException

二、排查

上面错误信息中，有两行提示，我们摘出来

## 查看完整错误栈信息，可以添加-e 参数
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
## 查看完整的debug日志，可以添加-X 参数
[ERROR] Re-run Maven using the -X switch to enable full debug logging.

1. 使用-e参数重新install

我们进入到client文件夹下，使用-e参数重新打包试试，看看它的异常栈信息

cd client
mvn clean install -e

2. 查看异常栈

异常栈很长查看最后一个即可，错误栈截图如下

清晰明了，打包异常的原因，就是因为没有找到org.example:project-test:pom:1.0-SNAPSHOT这个包！

三、解决

上面异常栈中org.example:project-test:pom:1.0-SNAPSHOT这个包，也就是子模块的父项目，即项目本身project-test。打包一下这个父项目，就能解决了。

结论

client打包时依赖common，而common依赖父工程project-test。
所以client先去本地查找project-test这个包；没找到就去私服中找，肯定还没找到；进而去*仓库查找，还是没找到，就报错了！

四、授之以渔

1. 遇到打包错误的情况不要慌，直接加-X或者-e参数重新打包，看看错误日志是什么，一般都会显示很清楚的。
   -X 参数：显示打包过程中的debug日志
   -e 参数：显示完成错误栈信息
2. 仔细看错误信息
   我们把最初的报错信息再摘出来一段：
   [ERROR] Failed to execute goal on project client: Could not resolve dependencies for project org.example:client:jar:1.0-SNAPSHOT: Failed to collect dependencies at org.example:common:jar:1.0-SNAPSHOT: Failed to read artifact descriptor for org.example:common:jar:1.0-SNAPSHOT: Could not find artifact org.example:project-test:pom:1.0-SNAPSHOT -> [Help 1]
   直接看最后一个错误，也能很清晰的看到提示缺少project-test:pom:1.0-SNAPSHOT这个包。