获取code并重定向到回调地址链接：
https://open.weixin.qq.com/connect/oauth2/authorize?appid=wx702a005562417853&redirect_uri=http%3A%2F%2Fpinit.com%2FWeixin%2Fauthorize.do&response_type=code&scope=snsapi_userinfo&state=STATE&connect_redirect=1#wechat_redirect
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这坑坑了我好久