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

      https://open.weixin.qq.com/connect/qrconnect?appid=APPID&redirect_uri=REDIRECT_URI
      &response_type=code&scope=SCOPE&state=STATE#wechat_redirect

         所以根据以上的url我们出来的地址应该是这样：

           

        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"

         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

   https://api.weixin.qq.com/sns/oauth2/access_token?appid=APPID&secret=SECRET&code=CODE&grant_type=authorization_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

     https://api.weixin.qq.com/sns/userinfo?access_token=ACCESS_TOKEN&openid=OPENID&lang=zh_CN

{ 
"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

}

    5、下面的回调整体代码

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 = "你自己的";
    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("");
                        log.info("");
                        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);
            }
		}
	}

}

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wxLogin来处理自定义页面来显示二维码,详细可以看官方文档