错误信息：
Failure to transfer org.springframework.boot:spring-boot-maven-plugin:pom:2.1.0.RELEASE 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 public has elapsed or updates are forced. Original error: Could not transfer artifact org.springframework.boot:spring-boot-maven-plugin:pom:2.1.0.RELEASE from/to public (http://maven.aliyun.com/nexus/content/groups/public/): maven.aliyun.com
解决办法：
在本地仓库中删除C:\Users\lenovo\.m2\repository\org\springframework\boot\spring-boot-maven-plugin文件夹，
然后在项目上单击右键，选择Maven -> Update Project...，如下图所示：
