Failure to transfer org.apache.maven.plugins:maven-resources-plugin:pom:2.7

导入maven项目时，pom.xml文件报错如下：

Failure to transfer org.apache.maven.plugins:maven-resources-plugin:pom:2.7 from 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. Original error: Could not transfer artifact .......

原因:

maven的plugin并未下载到本地。
查看maven库E:\java12\ProgRepository\maven_repository\org\apache\maven\plugins\maven-resources-plugin\2.7的话,会发现里面只有一个
maven-surefire-plugin-2.7.1.pom.lastUpdated的文件.
而并没有maven-surefire-plugin-2.7.1.jar

解决办法:

1.删除所有以lastUpdated结尾的文件
2.右键点击project -> Maven - Update Dependencies（Update Project...）

如果点击更新后发现
~.m2\repository\org\apache\maven\plugins\maven-surefire-plugin\2.7.1
下还是没有maven-surefire-plugin-2.7.1.jar
去* http://repo1.maven.org/maven2/org/apache/maven/plugins/maven-surefire-plugin/2.7.1/ *下载
maven-surefire-plugin-2.7.1.jar
maven-surefire-plugin-2.7.1.jar.sha1
maven-surefire-plugin-2.7.1.pom
maven-surefire-plugin-2.7.1.pom.sha1
包再重复步骤2.

结果如下：