myeclipse 创建 maven 项目pox出错? 400 报错

myeclipse 创建 maven 项目pox出错? 400 报错 Failure to transfer org.codehaus.plexus:plexus-classworlds:pom:1.2-alpha-9 from http://maven.oschina.net/content/groups/
 public/ was cached in the local repository, resolution will not be reattempted until the update interval of CN has elapsed or 
 updates are forced. Original error: Could not transfer artifact org.codehaus.plexus:plexus-classworlds:pom:1.2-alpha-9 from/
 to CN (http://maven.oschina.net/content/groups/public/): Read timed out