已经move掉了
这个函数叫move_uploaded_file 不叫 copy_uploaded_file
The file will be deleted from the temporary directory at the end of the request if it has not been moved away or renamed.
http://php.net/manual/en/features.file-upload.post-method.php
感谢 @xelz 和其它回答问题的朋友
如过你不去移动上传的文件、那么该文件就会在脚本周期执行完毕后自动删除
