java 微信小程序code获取openid的操作

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.moszk.frame.basic.utils.HttpRequest;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import java.util.HashMap;
import java.util.Map;
@RestController
public class WeiXinSubmitController {
    @ResponseBody
    @RequestMapping(value = "/wx/decodeUserInfo", method = RequestMethod.GET)
    public Map decodeUserInfo(String code) {
        System.out.println(code);
        Map map = new HashMap();
        //登录凭证不能为空
        if (code == null || code.length() == 0) {
            map.put("status", 0);
            map.put("msg", "code 不能为空");
            return map;
        }
        //小程序唯一标识   (在微信小程序管理后台获取)
        
        String wxspAppid = "***********";
        //小程序的 app secret (在微信小程序管理后台获取)
        String wxspSecret = "*********************";
        //授权（必填）
        String grant_type = "authorization_code";
        //https://api.weixin.qq.com/sns/jscode2session?appid=APPID&secret=SECRET&js_code=JSCODE&grant_type=authorization_code
        //1、向微信服务器 使用登录凭证 code 获取 session_key 和 openid
        //请求参数
        String params = "appid=" + wxspAppid + "&secret=" + wxspSecret + "&js_code=" + code + "&grant_type=" + grant_type;
        //发送请求
        String sr = HttpRequest.sendGet("https://api.weixin.qq.com/sns/jscode2session", params);
        System.out.println("sr========"+sr);
        //解析相应内容（转换成json对象）
        JSONObject json =JSON.parseObject(sr);
        System.out.println("json============"+json);
        //获取会话密钥（session_key）json.get("session_key").toString();
        String session_key = json.get("session_key").toString();
        //用户的唯一标识（openid）
        String openid = (String) json.get("openid");
        map.put("session_key",session_key);
        map.put("openid",openid);
        return map;
    }
}

import java.io.*;
import java.net.URL;
import java.net.URLConnection;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.text.SimpleDateFormat;
import java.util.*;
public class HttpRequest {
    
    public static String sendGet(String url, String param) {
        String result = "";
        BufferedReader in = null;
        try {
            String urlNameString = url + "?" + param;
            URL realUrl = new URL(urlNameString);
            // 打开和URL之间的连接
            URLConnection connection = realUrl.openConnection();
            // 设置通用的请求属性
            connection.setRequestProperty("accept", "*
    public static String sendPost(String url, String param, String keyValue) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            // 打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            // 设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("api-key", keyValue);  
            conn.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
			conn.setRequestProperty("Accept-Charset", "UTF-8");
            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 获取URLConnection对象对应的输出流
            //out = new PrintWriter(conn.getOutputStream());
			out = new PrintWriter(new OutputStreamWriter(conn.getOutputStream(), "UTF-8"));
            // 发送请求参数
            out.print(param);
            // flush输出流的缓冲
            out.flush();
            // 定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(
                      new InputStreamReader(conn.getInputStream(),"UTF-8"));
            String line;
            while ((line = in.readLine()) != null) {
            	System.out.println(line);
                result += line;
            }
        } catch (Exception e) {
            System.out.println("发送 POST 请求出现异常！"+e);
            e.printStackTrace();
        }
        //使用finally块来关闭输出流、输入流
        finally{
            try{
                if(out!=null){
                    out.close();
                }
                if(in!=null){
                    in.close();
                }
            }
            catch(IOException ex){
                ex.printStackTrace();
            }
        }
        return result;
    }
    
    public static String generateOrderId(){
		String keyup_prefix=new SimpleDateFormat("yyyyMMddHHmmss").format(new Date());
        String keyup_append= String.valueOf(new Random().nextInt(899999)+100000);
        String pay_orderid=keyup_prefix+keyup_append;//订单号
		return pay_orderid;
	}
	public static String generateTime(){
		return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
	}
    	
	public static String md5(String str) throws NoSuchElementException {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(str.getBytes("UTF-8"));
            byte[] byteDigest = md.digest();
            int i;
            //字符数组转换成字符串
            StringBuffer buf = new StringBuffer("");
            for (int offset = 0; offset < byteDigest.length; offset++) {
                i = byteDigest[offset];
                if (i < 0)
                    i += 256;
                if (i < 16)
                    buf.append("0");
                buf.append(Integer.toHexString(i));
            }
            // 32位加密
            return buf.toString();//toUpperCase
            // 16位的加密
             //return buf.toString().substring(8, 24).toUpperCase();
        } catch (NoSuchAlgorithmException | UnsupportedEncodingException e) {
            e.printStackTrace();
            return null;
        }
    }
}