Springboot如何实现网站第三方登录

public interface WeChatAuthService extends AuthService {
  public JSONObject getUserInfo(String accessToken, String openId);
}

@Service
public class WeChatAuthServiceImpl extends DefaultAuthServiceImpl implements WeChatAuthService {

  private Logger logger = LoggerFactory.getLogger(WeChatAuthServiceImpl.class);

//请求此地址即跳转到二维码登录界面
  private static final String AUTHORIZATION_URL =
      "https://open.weixin.qq.com/connect/qrconnect?appid=%s&redirect_uri=%s&response_type=code&scope=%s&state=%s#wechat_redirect";

  // 获取用户 openid 和access——toke 的 URL
  private static final String ACCESSTOKE_OPENID_URL =
      "https://api.weixin.qq.com/sns/oauth3/access_token?appid=%s&secret=%s&code=%s&grant_type=authorization_code";

  private static final String REFRESH_TOKEN_URL =
      "https://api.weixin.qq.com/sns/oauth3/refresh_token?appid=%s&grant_type=refresh_token&refresh_token=%s";

  private static final String USER_INFO_URL =
      "https://api.weixin.qq.com/sns/userinfo?access_token=%s&openid=%s&lang=zh_CN";

  private static final String APP_ID="xxxxxx";
  private static final String APP_SECRET="xxxxxx";
  private static final String SCOPE = "snsapi_login";

  private String callbackUrl = "https://www.xxx.cn/auth/wechat"; //回调域名

  @Override
  public String getAuthorizationUrl() throws UnsupportedEncodingException {
    callbackUrl = URLEncoder.encode(callbackUrl,"utf-8");
    String url = String.format(AUTHORIZATION_URL,APP_ID,callbackUrl,SCOPE,System.currentTimeMillis());
    return url;
  }


  @Override
  public String getAccessToken(String code) {
    String url = String.format(ACCESSTOKE_OPENID_URL,APP_ID,APP_SECRET,code);

    UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(url);
    URI uri = builder.build().encode().toUri();

    String resp = getRestTemplate().getForObject(uri, String.class);
    logger.error("getAccessToken resp = "+resp);
    if(resp.contains("openid")){
      JSONObject jsonObject = JSONObject.parseObject(resp);
      String access_token = jsonObject.getString("access_token");
      String openId = jsonObject.getString("openid");;

      JSONObject res = new JSONObject();
      res.put("access_token",access_token);
      res.put("openId",openId);
      res.put("refresh_token",jsonObject.getString("refresh_token"));

      return res.toJSONString();
    }else{
      throw new ServiceException("获取token失败，msg = "+resp);
    }
  }

  //微信接口中，token和openId是一起返回，故此方法不需实现
  @Override
  public String getOpenId(String accessToken) {
    return null;
  }

  @Override
  public JSONObject getUserInfo(String accessToken, String openId){
    String url = String.format(USER_INFO_URL, accessToken, openId);
    UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(url);
    URI uri = builder.build().encode().toUri();

    String resp = getRestTemplate().getForObject(uri, String.class);
    logger.error("getUserInfo resp = "+resp);
    if(resp.contains("errcode")){
      throw new ServiceException("获取用户信息错误，msg = "+resp);
    }else{
      JSONObject data =JSONObject.parseObject(resp);

      JSONObject result = new JSONObject();
      result.put("id",data.getString("unionid"));
      result.put("nickName",data.getString("nickname"));
      result.put("avatar",data.getString("headimgurl"));

      return result;
    }
  }

  //微信的token只有2小时的有效期，过时需要重新获取，所以官方提供了
  //根据refresh_token 刷新获取token的方法，本项目仅仅是获取用户
  //信息，并将信息存入库，所以两个小时也已经足够了
  @Override
  public String refreshToken(String refresh_token) {

    String url = String.format(REFRESH_TOKEN_URL,APP_ID,refresh_token);

    UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(url);
    URI uri = builder.build().encode().toUri();

    ResponseEntity<JSONObject> resp = getRestTemplate().getForEntity(uri,JSONObject.class);
    JSONObject jsonObject = resp.getBody();

    String access_token = jsonObject.getString("access_token");
    return access_token;
  }
}

@RequestMapping(value = "/wxLoginPage",method = RequestMethod.GET)
  public JSONObject wxLoginPage() throws Exception {
    String uri = weChatAuthService.getAuthorizationUrl();
    return loginPage(uri);
  }

  @RequestMapping(value = "/wechat")
  public void callback(String code,HttpServletRequest request,HttpServletResponse response) throws Exception {
    String result = weChatAuthService.getAccessToken(code);
    JSONObject jsonObject = JSONObject.parseObject(result);

    String access_token = jsonObject.getString("access_token");
    String openId = jsonObject.getString("openId");
//    String refresh_token = jsonObject.getString("refresh_token");

    // 保存 access_token 到 cookie，两小时过期
    Cookie accessTokencookie = new Cookie("accessToken", access_token);
    accessTokencookie.setMaxAge(60 *2);
    response.addCookie(accessTokencookie);

    Cookie openIdCookie = new Cookie("openId", openId);
    openIdCookie.setMaxAge(60 *2);
    response.addCookie(openIdCookie);

    //根据openId判断用户是否已经登陆过
    KmsUser user = userService.getUserByCondition(openId);

    if (user == null) {
      response.sendRedirect(request.getContextPath() + "/student/html/index.min.html#/bind?type="+Constants.LOGIN_TYPE_WECHAT);
    } else {
      //如果用户已存在，则直接登录
      response.sendRedirect(request.getContextPath() + "/student/html/index.min.html#/app/home?open_id=" + openId);
    }
  }