导入项目时提示Eclipse Some projects cannot be imported because they already exist in the works

多次导入同一个项目时提示Some projects cannot be imported because they already exist in the works；导致导入不了项目；

解决办法：找到eclipse的工作空间下的.metadata文件；删除此问题；重启eclipse再次导入项目；

E:workspace_E.metadata