小程序登录

1，准备工作需要小程序appid和secret
2，在controller定义一个方法
@ApiOperation(value = "通过code登录")
@GetMapping("/getTokenByCode")
public R getTokenByCode(@RequestParam(value = "code") String code) {
return loginService.getTokenByCode(code);
}

3，接口 R getTokenByCode(String code);
4，接口实现类
   public R getWxOpenIdForWxServer(String code) {
        try {
            Map<String, Object> map = new HashMap<String, Object>();
            map.put("appid", appid);
            map.put("secret",secret);
            map.put("grant_type", "authorization_code");
            map.put("js_code", code);
            log.info("获取openid参数打印:{}", JSONObject.toJSONString(map));
            String result = HttpUtil.get("https://api.weixin.qq.com/sns/jscode2session",map);
            log.info("获取openid返回值打印:{}", result);
            if (StringUtils.isNotEmpty(result)) {
                JSONObject jsonObject = JSONObject.parseObject(result);
if(jsonObject.getIntValue("errcode")== 0){
JSONObject resultJson = new JSONObject();
resultJson.put("openId", jsonObject.getString("openid"));
resultJson.put("sessionKey", jsonObject.getString("session_key"));
return R.ok(resultJson);
}
            }
        } catch (Exception e) {
            log.error("从微信服务端获取openid信息异常:{}", e);
        }
return R.error();
    }

R result = webChatUtil.getWxOpenIdForWxServer(code);
if (result.getCode() !=0) {
return R.failed(“失败”);
}
// 获取openid
JSONObject jsonObject = JSONObject.parseObject(result.getData().toString());
String openid= jsonObject.getString("openId");