@Override
    public User saveWeChatUser(String code) {

        //1、通过openAppid和openAppsecret和微信返回的code，拼接URL
        String accessTokenUrl = String.format(WeChatConfig.getOpenAccessTokenUrl(),weChatConfig.getOpenAppid(),weChatConfig.getOpenAppsecret(),code);

        //2、通过URL再去回调微信接口 (使用了httpclient和gson工具）
        Map<String ,Object> baseMap =  HttpUtils.doGet(accessTokenUrl);

        //3、回调成功后获取access_token和oppid
        if(baseMap == null || baseMap.isEmpty()){ return  null; }
        String accessToken = (String)baseMap.get("access_token");
        String openId  = (String) baseMap.get("openid");

        //4、去数据库查看该用户之前是否已经扫码登陆过（openid是用户唯一标志）
        User dbUser = userMapper.findByopenid(openId);

        if(dbUser!=null) { //如果用户已经存在，直接返回
            return dbUser;
        }

        //4、access_token和openid拼接URL
        String userInfoUrl = String.format(WeChatConfig.getOpenUserInfoUrl(),accessToken,openId);

        //5、通过URL再去调微信接口获取用户基本信息
        Map<String ,Object> baseUserMap =  HttpUtils.doGet(userInfoUrl);

        if(baseUserMap == null || baseUserMap.isEmpty()){ return  null; }

        //6、获取用户姓名、性别、城市、头像等基本信息
        String nickname = (String)baseUserMap.get("nickname");
        Double sexTemp  = (Double) baseUserMap.get("sex");
        int sex = sexTemp.intValue();
        String province = (String)baseUserMap.get("province");
        String city = (String)baseUserMap.get("city");
        String country = (String)baseUserMap.get("country");
        String headimgurl = (String)baseUserMap.get("headimgurl");
        StringBuilder sb = new StringBuilder(country).append("||").append(province).append("||").append(city);
        String finalAddress = sb.toString();
        try {
            //解决用户名乱码
            nickname = new String(nickname.getBytes("ISO-8859-1"), "UTF-8");
            finalAddress = new String(finalAddress.getBytes("ISO-8859-1"), "UTF-8");

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        //7、新用户存入数据库
        User user = new User();
        user.setName(nickname);
        user.setHeadImg(headimgurl);
        user.setCity(finalAddress);
        user.setOpenid(openId);
        user.setSex(sex);
        user.setCreateTime(new Date());
        userMapper.save(user);
        return user;
    }

     <!--httpclient相关jar包-->
        <dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpclient</artifactId>
                <version>4.5.3</version>
            </dependency>
            <dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpmime</artifactId>
                <version>4.5.2</version>
            </dependency>

            <dependency>
                <groupId>commons-codec</groupId>
                <artifactId>commons-codec</artifactId>
            </dependency>
            <dependency>
                <groupId>commons-logging</groupId>
                <artifactId>commons-logging</artifactId>
                <version>1.1.1</version>
            </dependency>
                    <dependency>
                    <groupId>org.apache.httpcomponents</groupId>
                    <artifactId>httpcore</artifactId>
            </dependency>

        <!-- gson工具，封装http的时候使用 -->
        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.8.0</version>
        </dependency>

/**
 * 封装http get post
 */
public class HttpUtils {

    private static  final Gson gson = new Gson();

    /**
     * get方法
     * @param url
     * @return
     */
    public static Map<String,Object> doGet(String url){

        Map<String,Object> map = new HashMap<>();
        CloseableHttpClient httpClient =  HttpClients.createDefault();

        RequestConfig requestConfig =  RequestConfig.custom().setConnectTimeout(5000) //连接超时
                .setConnectionRequestTimeout(5000)//请求超时
                .setSocketTimeout(5000)
                .setRedirectsEnabled(true)  //允许自动重定向
                .build();

        HttpGet httpGet = new HttpGet(url);
        httpGet.setConfig(requestConfig);

        try{
           HttpResponse httpResponse = httpClient.execute(httpGet);
           if(httpResponse.getStatusLine().getStatusCode() == 200){

              String jsonResult = EntityUtils.toString( httpResponse.getEntity());
               map = gson.fromJson(jsonResult,map.getClass());
           }

        }catch (Exception e){
            e.printStackTrace();
        }finally {
            try {
                httpClient.close();
            }catch (Exception e){
                e.printStackTrace();
            }
        }
        return map;
    }


    /**
     * 封装post
     * @return
     */
    public static String doPost(String url, String data,int timeout){
        CloseableHttpClient httpClient =  HttpClients.createDefault();
        //超时设置

        RequestConfig requestConfig =  RequestConfig.custom().setConnectTimeout(timeout) //连接超时
                .setConnectionRequestTimeout(timeout)//请求超时
                .setSocketTimeout(timeout)
                .setRedirectsEnabled(true)  //允许自动重定向
                .build();

        HttpPost httpPost  = new HttpPost(url);
        httpPost.setConfig(requestConfig);
        httpPost.addHeader("Content-Type","text/html; chartset=UTF-8");

        if(data != null && data instanceof  String){ //使用字符串传参
            StringEntity stringEntity = new StringEntity(data,"UTF-8");
            httpPost.setEntity(stringEntity);
        }

        try{

            CloseableHttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            if(httpResponse.getStatusLine().getStatusCode() == 200){
                String result = EntityUtils.toString(httpEntity);
                return result;
            }

        }catch (Exception e){
            e.printStackTrace();
        }finally {
            try{
                httpClient.close();
            }catch (Exception e){
                e.printStackTrace();
            }
        }
        return null;
    }
}

HttpUtils