使用maven执行clean报错详情：

[ERROR] Plugin org.codehaus.mojo:build-helper-maven-plugin:1.10 or one of its dependencies could not be resolved: Failed to read artifact descriptor for org.codehaus.mojo:build-helper-maven-plugin:jar:1.10: Cannot access central (https://repo.maven.apache.org/maven2) in offline mode and the artifact org.codehaus.mojo:mojo-parent:pom:38 has not been downloaded from it before. -> [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/PluginResolutionException

报错关键：
“Cannot access central (https://repo.maven.apache.org/maven2) in offline mode and the artifact org.codehaus.mojo:mojo-parent:pom:38 has not been downloaded from it before.”

解决办法：
关闭offline按钮