小程序换取openId

package com.shanxilgong.linxi.controllers;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.shanxilgong.linxi.listener.MyTimerTask;
import org.apache.catalina.servlet4preview.http.HttpServletRequest;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.Map;

import static com.shanxilgong.linxi.tokenManager.TokenManager.tokenManager;

/**
 * 该接口用于换取openId，进行用户状态维护
 * 1、在进行参数绑定时，默认是必填参数。
 * 2、微信小程序侧在传递参数时，使用Get方法，
 *    将wx.login()获取到的临时凭证拼接值url后面
 *
 * 小程序当前实现逻辑：
 *      小程序页签每次进入到“我的”页签都会自动登录。
 *
 *    返回值： {"session_key":"JHdZspvydvulDWF8BnfUew==","expires_in":7200,"openid":"oGo8D0RMEW4KK55RMOpQR2XaJQA8"}
 *    过期时间，单位为秒，1小时=1*60*60  过期时间是2小时
 */
@RestController
@RequestMapping(value = {"/login"},method = RequestMethod.GET)
public class LoginGetInfo
{
    // Spring boot 里面本身已经集成了 log4j 的jar相关
    private static Logger logger = LoggerFactory.getLogger(LoginGetInfo.class);

    @Value("${appid}")
    private String appid;

    @Value("${secret}")
    private String secret;

    private static final  String URL =
            "https://api.weixin.qq.com/sns/jscode2session?" +
                    "appid=APPID&secret=SECRET&js_code=JSCODE&grant_type=authorization_code";

    @RequestMapping(value = {"/getInfo"})
    public JSONObject getInfo(@RequestParam(value = "data") String  js_code,
                              HttpServletRequest request, HttpServletResponse response)
    {

        JSONObject result = new JSONObject();
        HttpClient httpClient=new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(
                URL.replace("APPID",appid)
                        .replace("SECRET",secret)
                        .replace("JSCODE",js_code));
        try
        {
            HttpResponse resp =  httpClient.execute(httpGet);
            if(200 != resp.getStatusLine().getStatusCode())
            {
                logger.error("execute request of get is error.");
                result.put("code","-1");
                result.put("msg","error");
                return result;
            }
            HttpEntity entity=resp.getEntity();
            String msg= EntityUtils.toString(entity,"utf-8");
            JSONObject json = JSON.parseObject(msg);
            String openId = json.getString("openid"); // 拿到当前用户在微信服务器的唯一凭证

            // 在token缓存中去查看当前用户的凭证是否已经存在
            if (!tokenManager.containsKey(openId))
            {
                // 添加用户凭证
                tokenManager.put(openId,true);
            }
        }
        catch (IOException e)
        {
            logger.error("execute request of get is error.");
            result.put("code","-1");
            result.put("msg","error");
            return result;
        }
        result.put("code","0");
        result.put("msg","success");
        return result;
    }
}