No goals have been specified for this build. You must specify a valid lifecycle phase or a goal ...

eclipse打包springboot项目，打成jar包报错。

[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.417 s
[INFO] Finished at: 2020-03-20T11:59:00+08:00
[INFO] ------------------------------------------------------------------------
[ERROR] Plugin org.apache.maven.plugins:maven-clean-plugin:3.1.0 or one of its dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-clean-plugin:jar:3.1.0: Could not transfer artifact org.apache.maven.plugins:maven-clean-plugin:pom:3.1.0 from/to Central (http://repo1.maven.org/maven2): Failed to transfer http://repo1.maven.org/maven2/org/apache/maven/plugins/maven-clean-plugin/3.1.0/maven-clean-plugin-3.1.0.pom. Error code 501, HTTPS Required -> [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

解决方法： 
删除自己修改的仓库的的插件目录下的所有文件，重新build 
如：maven仓库位置\org\apache\maven\plugins 
删除此目录下的所有文件，然后重新build，如：mvn clean

 

另外，阿里最近更新了，不再支持http下载，只支持https，你需要把maven配置中的http://换成https://。

阿里云镜像如下：

<mirror>
<id>alimaven-new</id>
<mirrorOf>central</mirrorOf>
<name>aliyun maven</name>
<url>https://maven.aliyun.com/repository/central/</url>
</mirror>