第一次从外部文件导入HelloWorld工程到workspace目录中,成功. 删除后,再次从外部导入workspace目录提示 Some projects cannot be imported because they already exist in the workspace eclipse中删除HelloWorld工程时没有勾选Delete project contents on disk(cannot be undone)则不会删除文件. 这时再次添加HelloWorld工程时提示 S