文件上传，图片上传(后缀名验证，文件类型验证)，大文件分片上传，“秒传”，断点续传，传输失败自动重试，手动重试(f i l e u p l o a d.p i c t u r e u p l o a d.)

自己写的Java多线程下载类，可以自己定义下载线程，自己定义下载目录，带断点续传(Write multi-threaded Java download, you can define their own download thread, define your own download directory, with http)