微信网页二维码授权登陆

一、首先要了解微信网页授权登录肯定是先去官网看文档。网页授权获取用户基本信息

二、文档里面无非就是几步操作：

下面这个图有必要复制过来，作为一个程序猿，接第三方的功能还是要明白业务流程



1、首先你需要在微信开放平台注册和认证，认证完毕以后网站应用中添加网站应用，在里面添加必要的信息以及很重要的授权回调域，审核通过以后就可以拿到APPID和SECRET，这个就是2个神器参数

2、在你自己的按钮点击事件中去调用微信提供获取code值得url地址：

特别需要注意的是：REDIRECT_URI参数在页面上需要用encodeURIComponent(REDIRECT_URI)编码，不然微信会一直报redirect_uri参数异常，APPID填入上面申请好的scope填写snsapi_login，state主要防止csrf攻击（跨站请求伪造攻击），你自己可以生成随机或者sessionid

<span style="font-size:14px;">      https://open.weixin.qq.com/connect/qrconnect?appid=APPID&redirect_uri=REDIRECT_URI &response_type=code&scope=SCOPE&state=STATE#wechat_redirect</span>

所以根据以上的url我们出来的地址应该是这样：

<span style="font-size:14px;">        var url = encodeURIComponent("http://xxxx.com/pubService/weChatLogin");
window.location.href="https://open.weixin.qq.com/connect/qrconnect?appid=你自己的appid&redirect_uri="+url+"&response_type=code&scope=snsapi_login
&state=3d6be0a4035d839573b04816624a415e#wechat_redirect"</span>

3、现在我们需要写回调代码来处理获取的code值，我们需要通过code获取access_token

<span style="font-size:14px;">   https://api.weixin.qq.com/sns/oauth2/access_token?appid=APPID&secret=SECRET&code=CODE&grant_type=authorization_code</span>[/code] 
{

"access_token":"ACCESS_TOKEN",

"expires_in":7200,

"refresh_token":"REFRESH_TOKEN",

"openid":"OPENID", 授权用户唯一标识

"scope":"SCOPE",
"unionid": "o6_bmasdasdsad6_2sgVt7hMZOPfL"
}


    4、根据返回的openid去获取相应的微信用户信息

<span style="font-size:14px;">     <span' target='_blank'>https://api.weixin.qq.com/sns/userinfo?access_token=ACCESS_TOKEN&openid=OPENID&lang=zh_CN</span>
<span style="font-size:14px;">{
"openid":"OPENID",
"nickname":"NICKNAME",普通用户昵称
"sex":1,  1为男性，2为女性
"province":"PROVINCE",  省份
"city":"CITY", 城市
"country":"COUNTRY", 国家
"headimgurl": "http://wx.qlogo.cn/mmopen/g3MonUZtNHkdmzicIlibx6iaFqAc56vxLSUfpb6n5WKSYVY0ChQKkiaJSgQ1dZuTOgvLLrhJbERQQ4eMsv84eavHiaiceqxibJxCfHe/0",头像
"privilege":[
"PRIVILEGE1",
"PRIVILEGE2"
],  用户特权信息
"unionid": " o6_bmasdasdsad6_2sgVt7hMZOPfL"  用户统一标识

}</span>


   5、下面的回调整体代码

<span style="font-size:14px;">package net.dreams9.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.dreams9.util.HttpsConnectUtil;

import org.apache.log4j.Logger;

import com.alibaba.fastjson.JSONObject;

/**
* Servlet implementation class WeinXinChatLogin
*/
@WebServlet("/weChatLogin")
public class WeinXinChatServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final String ACCESS_TOKEN_URL = "https://api.weixin.qq.com/sns/oauth2/access_token?appid=APPID&secret=SECRET&code=CODE&grant_type=authorization_code";
private static final String APPID = "你自己";
private static final String SECRET = "</span><span style="font-size:14px;">你自己的</span><span style="font-size:14px;">";
private static final String SNS_URL = "https://api.weixin.qq.com/sns/userinfo?access_token=ACCESS_TOKEN&openid=OPENID&lang=zh_CN";
private static final Logger log = Logger.getLogger(WeinXinChatServlet.class);
/**
* @see HttpServlet#HttpServlet()
*/
public WeinXinChatServlet() {
super();
// TODO Auto-generated constructor stub
}

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String code = request.getParameter("code");
if(code != null && !"".equals(code)){
try {
String rsp = HttpsConnectUtil.doGet(ACCESS_TOKEN_URL.replace("CODE", code).replace("APPID", APPID).replace("SECRET", SECRET), "", "");
if(rsp != null && !"".equals(rsp)){
JSONObject data = JSONObject.parseObject(rsp);
if(data.containsKey("errcode")){
throw new Exception(data.getString("errmsg"));
}
String access_token = data.getString("access_token");
String openid = data.getString("openid");
//获取当前授权微信用户的信息
rsp = HttpsConnectUtil.doGet(SNS_URL.replace("ACCESS_TOKEN", access_token).replace("OPENID", openid), "", "");
if(rsp != null && !"".equals(rsp)){
data = JSONObject.parseObject(rsp);
if(data.containsKey("errcode")){
throw new Exception(data.getString("errmsg"));
}
log.info("weixin info:"+data.toJSONString());
//返回json信息到网页上面
PrintWriter writer = response.getWriter();
response.setHeader("Pragma", "no-cache");   // HTTP/1.0 caches might not implement Cache-Control and might only implement Pragma: no-cache
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
response.setContentType("text/html; charset=UTF-8");
writer.write("<script>window.dialogArguments.callBack('"+data.toJSONString()+"');window.close();</script>");
log.info("<script>window.returnValue='"+data.toJSONString()+"';window.close();</script>");
writer.flush();
writer.close();

}
else{
throw new Exception("获取微信用户信息失败！！");
}
}
else{
throw new Exception("通过code获取access_token失败！！！");
}
} catch (Exception e) {
log.error(e.getMessage(), e);
}
}
}

}</span>


6、实际效果就是在网页是调用第2步的地址就会出现一个二维码,我们手机打开微信，扫描二微码就可以实现微信登录，当然，也可以用[b]wxLogin来处理自定义页面来显示二维码,详细可以看官方文档[/b]