生成的文件可以放在 utils文件中哦！！！
/*
* A JavaScript implementation of the RSA Data Security, Inc. MD5 Message
* Digest Algorithm, as defined in RFC 1321.
* Version 1.1 Copyright (C) Paul Johnston 1999 - 2002.
* Code also contributed by Greg Holt
* See http://pajhome.org.uk/site/legal.html for details
