1 微信开放平台(https://open.weixin.qq.com/)资质认证并申请创建网站应用,拿到appId和appSecret以及回调url,已有的可跳过

   

2 后端将获取扫码用的二维码地址返回给前台

   

@Override
public Response getWechatQrCode() {try {LOGGER.info("开始获取微信登录二维码:");String oauthUrl = "https://open.weixin.qq.com/connect/qrconnect?            appid=APPID&redirect_uri=REDIRECT_URI&response_type=code&scope=SCOPE&state=STATE#wechat_redirect";String redirect_uri = URLEncoder.encode(Constant.WX_OPEN_REDIRECT_URL, "utf-8");System.out.println("redirect_uri:"+redirect_uri);oauthUrl =  oauthUrl.replace("APPID",Constant.WX_OPEN_APP_ID).replace("REDIRECT_URI",redirect_uri).replace("SCOPE",Constant.WX_OPEN_SCOPE);LOGGER.info("oauthUrl:"+oauthUrl);return new Response(Constant.RES_SUCCESS, "获取微信登录二维码成功", oauthUrl);} catch (Exception e) {LOGGER.info("获取微信登录二维码失败:"+e);Utils.getExceptionDetail(e);return new Response(Constant.RES_ERROR_SERVER,"服务器内部错误");}
}

  上面scope的值为snsapi_login,前端拿到oauthUrl就可以直接请求到微信扫码的页面

   

3 用户扫码之后就可以拿到code,使用code获取access_token和openid

   

4 用access_token和openid就可以获取用户的信息了

5 拿到用户信息(userInfoStr)了接下来就是判断用户是否存在,再做其他自定义代码的事了,如:

  

  至此网页微信扫码登录就算完成了,其中3-4步中的源码如下:

   

//通过code获取access_token
String url = "https://api.weixin.qq.com/sns/oauth2/access_token?appid=APPID&secret=SECRET&code=CODE&grant_type=authorization_code";
url = url.replace("APPID",Constant.WX_OPEN_APP_ID).replace("SECRET",Constant.WX_OPEN_APP_SECRET).replace("CODE",code);
JSONObject tokenInfoObject = HttpUtils.httpGet(url);
LOGGER.info("tokenInfoObject:{}",tokenInfoObject);//通过access_token和openid获取用户信息
String userInfoUrl = "https://api.weixin.qq.com/sns/userinfo?access_token=ACCESS_TOKEN&openid=OPENID";
userInfoUrl = userInfoUrl.replace("ACCESS_TOKEN",tokenInfoObject.getString("access_token")).replace("OPENID",tokenInfoObject.getString("openid"));
JSONObject userInfoStr = HttpUtils.httpGet(userInfoUrl);
LOGGER.info("userInfoStr:{}",userInfoStr);

  上面用到的HttpUtils工具类:

   

package com.hy.bjggwhy.util;import com.alibaba.fastjson.JSONObject;
import org.apache.http.HttpEntity;
import org.apache.http.HttpStatus;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;import java.io.IOException;/*** @author zhangmy* @date 2019-12-26 10:45* @description*/
public class HttpUtils {private static Logger logger = LoggerFactory.getLogger(HttpUtils.class);private static RequestConfig requestConfig = null;static {// 设置请求和传输超时时requestConfig = RequestConfig.custom().setSocketTimeout(2000).setConnectTimeout(2000).build();}/*** post请求传输json参数** @param url       url地址* @param jsonParam 参数* @return*/public static JSONObject httpPost(String url, JSONObject jsonParam) {// post请求返回结果CloseableHttpClient httpClient = HttpClients.createDefault();JSONObject jsonResult = null;HttpPost httpPost = new HttpPost(url);// 设置请求和传输超时时请求httpPost.setConfig(requestConfig);try {System.out.println(jsonParam);if (null != jsonParam) {// 解决中文乱码问题StringEntity entity = new StringEntity(jsonParam.toString(), "utf-8");entity.setContentEncoding("UTF-8");entity.setContentType("application/json");httpPost.setEntity(entity);}System.out.println(jsonParam);CloseableHttpResponse result = httpClient.execute(httpPost);// 请求发请求成功，并得到响应if (result.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {String str = "";try {// 读取服务器返回过来的json字符串数str = EntityUtils.toString(result.getEntity(), "utf-8");// 把json字符串转换成json对象jsonResult = JSONObject.parseObject(str);} catch (Exception e) {logger.error("post请求提交失败:" + url, e);}}} catch (IOException e) {logger.error("post请求提交失败:" + url, e);} finally {httpPost.releaseConnection();}return jsonResult;}/*** post请求传输String参数 例如：name=Jack&sex=1&type=2* Content-type:application/x-www-form-urlencoded** @param url      url地址* @param strParam 参数* @return*/public static JSONObject httpPost(String url, String strParam) {// post请求返回结果CloseableHttpClient httpClient = HttpClients.createDefault();JSONObject jsonResult = null;HttpPost httpPost = new HttpPost(url);httpPost.setConfig(requestConfig);try {if (null != strParam) {// 解决中文乱码问题StringEntity entity = new StringEntity(strParam, "utf-8");entity.setContentEncoding("UTF-8");entity.setContentType("application/x-www-form-urlencoded");httpPost.setEntity(entity);}CloseableHttpResponse result = httpClient.execute(httpPost);// 请求发宋成功，并得到响应if (result.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {String str = "";try {// 读取服务器返回过来的json字符串数据str = EntityUtils.toString(result.getEntity(), "utf-8");// 把json字符串转换成json对象jsonResult = JSONObject.parseObject(str);} catch (Exception e) {logger.error("post请求提交失败:" + url, e);}}} catch (IOException e) {logger.error("post请求提交失败:" + url, e);} finally {httpPost.releaseConnection();}return jsonResult;}/*** 发送get请求** @param url 路径* @return*/public static JSONObject httpGet(String url) {// get请求返回结果JSONObject jsonResult = null;CloseableHttpClient client = HttpClients.createDefault();// 发送get请求HttpGet request = new HttpGet(url);request.setConfig(requestConfig);try {CloseableHttpResponse response = client.execute(request);// 请求发送成功，并得到响应if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {// 读取服务器返回过来的json字符串数组HttpEntity entity = response.getEntity();String strResult = EntityUtils.toString(entity, "utf-8");// 把json字符串转换成json对象jsonResult = JSONObject.parseObject(strResult);} else {logger.error("get请求提交失败:" + url);}} catch (IOException e) {logger.error("get请求提交失败:" + url, e);} finally {request.releaseConnection();}return jsonResult;}
}