Java后端接入微信小程序实现登录功能

import cn.hutool.core.util.StrUtil;
import cn.hutool.http.HttpRequest;
import cn.hutool.json.JSONObject;
import com.redapple.project.common.ErrorCode;
import com.redapple.project.exception.ThrowUtils;

public class RequestUtils {

    // 获取AccessToken
    public static JSONObject getAccessToken(String appId, String appSecret) {
        String apiUrl = StrUtil.format(
                "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid={}&secret={}",
                appId, appSecret
        );
        String body = HttpRequest.get(apiUrl).execute().body();
        ThrowUtils.throwIf(body == null, ErrorCode.OPERATION_ERROR);
        return new JSONObject(body);
    }

    // 获取session_key和openid
    public static String getOpenIdByCode(String appId, String secret, String code) {
        String apiUrl = StrUtil.format(
                "https://api.weixin.qq.com/sns/jscode2session?appid={}&secret={}&js_code={}&grant_type=authorization_code",
                appId, secret, code
        );
        String body = HttpRequest.get(apiUrl).execute().body();
        ThrowUtils.throwIf(body == null, ErrorCode.OPERATION_ERROR);
        return body;
    }

}

    public LoginUserVO WeChatLogin(String appid, String secret, String code, HttpServletRequest request) {
        // 获取session_key和openid
        String result = RequestUtils.getOpenIdByCode(appid, secret, code);
        System.out.println("result:" + result);
        // 提取openid
        String openid = new JSONObject(result).getStr("openid");
        // 这里是自己封装的方法，流程是如果openid为空则抛异常
        ThrowUtils.throwIf(openid == null, ErrorCode.NOT_FOUND_ERROR, "openid为空");
        // 查询openid是否存在
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("openid", openid);
        User oldUser = this.baseMapper.selectOne(queryWrapper);
        // openid不存在
        if (oldUser == null) {
            // 添加用户
            User user = new User();
            user.setOpenid(openid);
            user.setPhone("手机号未填写");
            user.setUserName("默认用户");
            boolean saveResult = this.save(user);
            if (!saveResult) {
                // 这里也是自己封装的方法，流程是抛自定义异常
                throw new BusinessException(ErrorCode.SYSTEM_ERROR, "注册失败，数据库错误");
            }
            // 记录用户的登录态
            request.getSession().setAttribute(USER_LOGIN_STATE, user);
            return getLoginUserVO(user);
        }
        // 记录用户的登录态
        request.getSession().setAttribute(USER_LOGIN_STATE, oldUser);
        // 用户存在，返回用户数据
        return getLoginUserVO(oldUser);	// 自己封装的方法，返回脱敏的用户数据
    }

<template>
	<view>
		<button class="loginbutton" @click="login">微信一键登录</button>
	</view>
</template>
<script setup lang="ts">
    	const login = () => {
		uni.login({
			provider: 'weixin', //使用微信登录
			success: function (loginRes) {
				if (loginRes.code !== null) {
					console.log("获取code:" + loginRes.code)
					loginUser(loginRes.code);
				} else {
					console.log("code为空");
				}
			}
		})
	}
	const loginUser = (code: any) => {
		uni.request({
			url: "http://localhost:8066/api/wechat/login",
			method: 'POST',
			data: {
				code: code,
			},
			success: (res : any) => {
				//每次登录时清楚缓存
				uni.removeStorageSync('JSESSIONID');
				// 保存Cookie到Storage
				uni.setStorageSync("JSESSIONID", res.header['Set-Cookie'])
				if (res.data.code === 1) {
					uni.switchTab({
						url: "/pages/index/index"
					})
				} else {
					console.log(res);
				}
			}
		})
	}
</script>
<style>
</style>