运行Maven插件的命令提示插件版本在仓库中找不到

例：运行 mvn dependency:copy-dependencies -DoutputDirectory=lib 命令出现异常：

[WARNING] The POM for org.apache.maven.plugins:maven-dependency-plugin:jar:3.1.2 is missing, no dependency information available
[WARNING] Failed to retrieve plugin descriptor for org.apache.maven.plugins:maven-dependency-plugin:3.1.2: Plugin org.apache.maven.plugins:maven-dependency-plugin:3.1.2 or one of its dependencies could not be resolved: Failure to find org.apache.maven.plugins:maven-dependency-plugin:jar:3.1.2 in http://maven.aliyun.com/nexus/content/groups/public/ was cached in the local repository, resolution will not be reattempted until the update interval of alimaven has elapsed or updates are forced
[WARNING] The POM for org.apache.maven.plugins:maven-dependency-plugin:jar:3.1.2 is missing, no dependency information available

原因：该插件版本在本地及远程仓库中未找到。

解决：

    方案1：
        切换 Maven 远程仓库。

    方案2：
        修改 运行的插件版本：

        方式① 运行时指定版本：

mvn org.apache.maven.plugins:maven-dependency-plugin:3.1.1:copy-dependencies -DoutputDirectory=lib

        方式② pom 依赖中指定版本：

    
        
            
                org.apache.maven.plugins
                maven-dependency-plugin
                3.1.1
            
        
    

            然后再运行：

mvn dependency:copy-dependencies -DoutputDirectory=lib