http://blog.csdn.net/baronyang/article/details/44489841
http://www.oschina.net/code/snippet_2255303_46155
https://api.weixin.qq.com/sns/auth?access_token=ACCESS_TOKEN&openid=OPENID
http://files.cnblogs.com/files/wenjie/weixin.pdf
https://api.weixin.qq.com/sns/auth?access_token=ACCESS_TOKEN&openid=OPENID