各位大佬请教一个问题，我这里没有获得unionid的原因是小程序没有认证完成吗？

// app.js
App({
  onLaunch() {
    // 展示本地存储能力
    const logs = wx.getStorageSync('logs') || []
    logs.unshift(Date.now())
    wx.setStorageSync('logs', logs)


    // 登录
    wx.login({
      success: res => {
        // 发送 res.code 到后台换取 openId, sessionKey, unionId
        if (res.code) {
          // 发送 res.code 到后台换取 openId, sessionKey, unionId
          wx.request({
            url: 'http://localhost:8081/api/login',
            data: {
              code: res.code
            },
            success: function (response) {
              // 处理登录结果
              console.log(response.data);
            }
          })
        } else {
          console.log('登录失败！' + res.errMsg)
        }
      }
    })
  },
  globalData: {
    userInfo: null
  }
})


package com.msbd.backend.test;

import cn.dev33.satoken.stp.StpUtil;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import com.alibaba.fastjson.JSONObject;

@RestController
public class LoginController {

    private static final String APPID = "xxxxxxxxxxxxxxx";

    @GetMapping("/api/login")
    public String login(@RequestParam("code") String code) {
        try {
            // 假设这里使用 saToken 生成 JWT 令牌
            String jwtToken = StpUtil.getTokenInfo().getTokenValue();

            String url = "https://api.weixin.qq.com/sns/jscode2session?appid=" + APPID + "&secret=" + jwtToken + "&js_code=" + code + "&grant_type=authorization_code";
            URL obj = new URL(url);
            HttpURLConnection con = (HttpURLConnection) obj.openConnection();
            con.setRequestMethod("GET");
            BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
            String inputLine;
            StringBuffer response = new StringBuffer();
            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();
            JSONObject jsonObject = JSONObject.parseObject(response.toString());
            String unionid = jsonObject.getString("unionid");
            System.out.println("========================>unionid = " + unionid);
            // 根据 unionid 查找或创建用户
            // ...
            return "Login success with unionid: " + unionid;
        } catch (Exception e) {
            e.printStackTrace();
            return "Login failed";
        }
    }
}