第三方登录集成

OAuth2 统一接入模式

用户 → 选择第三方登录
  │
  ├─ 跳转第三方 OAuth 授权页
  │    ?response_type=code
  │    &client_id=APP_ID
  │    &redirect_uri=https://myapp/callback/{platform}
  │    &state=随机值
  │
  ├─ 用户授权 → 回调 code
  │
  ├─ 后端用 code 换 access_token
  │    POST /oauth/access_token
  │    appid=APP_ID&secret=APP_SECRET&code=CODE
  │
  ├─ 用 access_token 获取用户信息
  │    GET /userinfo?access_token=xxx
  │
  └─ 注册 / 登录（绑定本地账号或自动注册）

---

微信登录

开放平台流程

微信开放平台 → 网站应用 → AppID + AppSecret

public class WeChatLoginService {
    private static final String TOKEN_URL =
        "https://api.weixin.qq.com/sns/oauth2/access_token";
    private static final String USERINFO_URL =
        "https://api.weixin.qq.com/sns/userinfo";

    public WeChatUser login(String code) {
        // 1. 获取 access_token
        String resp = HttpUtil.get(TOKEN_URL, Map.of(
            "appid", appId,
            "secret", appSecret,
            "code", code,
            "grant_type", "authorization_code"
        ));
        JSONObject json = JSON.parseObject(resp);
        String token = json.getString("access_token");
        String openId = json.getString("openid");

        // 2. 获取用户信息
        String userResp = HttpUtil.get(USERINFO_URL, Map.of(
            "access_token", token,
            "openid", openId
        ));
        return JSON.parseObject(userResp, WeChatUser.class);
    }
}

---

钉钉登录

扫码模式

public class DingTalkLoginService {
    // 1. 构造扫码 URL（前端跳转）
    public String getQrCodeUrl() {
        return "https://login.dingtalk.com/oauth2/auth" +
            "?redirect_uri=" + URLEncoder.encode(redirectUri) +
            "&response_type=code" +
            "&client_id=" + appId +
            "&scope=openid" +
            "&state=STATE";
    }

    // 2. 回调处理
    public DingTalkUser login(String code) {
        // 获取 access_token
        JSONObject tokenResp = HttpUtil.post(
            "https://api.dingtalk.com/v1.0/oauth2/userAccessToken",
            Map.of("clientId", appId, "clientSecret", appSecret, "code", code)
        );
        String token = tokenResp.getString("accessToken");

        // 获取用户信息
        JSONObject userResp = HttpUtil.get(
            "https://api.dingtalk.com/v1.0/contact/users/me",
            Map.of("x-acs-dingtalk-access-token", token)
        );
        return userResp.toJavaObject(DingTalkUser.class);
    }
}

---

企业微信登录

public class WeComLoginService {
    // 构造授权 URL
    public String getAuthUrl() {
        return "https://open.weixin.qq.com/connect/oauth2/authorize" +
            "?appid=" + corpId +
            "&redirect_uri=" + URLEncoder.encode(redirectUri) +
            "&response_type=code" +
            "&scope=snsapi_privateinfo" +
            "&state=STATE#wechat_redirect";
    }

    // 获取用户信息
    public WeComUser login(String code) {
        // 获取 access_token（企业微信需先获取 corp access token）
        JSONObject tokenResp = HttpUtil.get(
            "https://qyapi.weixin.qq.com/cgi-bin/gettoken",
            Map.of("corpid", corpId, "corpsecret", corpSecret)
        );
        String token = tokenResp.getString("access_token");

        // 获取用户详情
        JSONObject userResp = HttpUtil.post(
            "https://qyapi.weixin.qq.com/cgi-bin/auth/getuserdetail",
            Map.of("access_token", token),
            Map.of("user_ticket", code)
        );
        return userResp.toJavaObject(WeComUser.class);
    }
}

---

飞书登录

public class FeishuLoginService {
    public FeishuUser login(String code) {
        // 获取 access_token
        JSONObject tokenResp = HttpUtil.post(
            "https://open.feishu.cn/open-apis/authen/v1/access_token",
            Map.of(
                "app_id", appId,
                "app_secret", appSecret,
                "grant_type", "authorization_code",
                "code", code
            )
        );
        String token = tokenResp.getJSONObject("data").getString("access_token");

        // 获取用户信息
        JSONObject userResp = HttpUtil.get(
            "https://open.feishu.cn/open-apis/authen/v1/user_info",
            Map.of("Authorization", "Bearer " + token)
        );
        return userResp.getJSONObject("data").toJavaObject(FeishuUser.class);
    }
}

---

统一登录网关设计

策略模式解耦

public interface OAuthLoginHandler {
    String getPlatform();
    OAuthUser login(String code);
}

@Component
public class OAuthLoginGateway {
    private final Map<String, OAuthLoginHandler> handlerMap;

    public OAuthLoginGateway(List<OAuthLoginHandler> handlers) {
        handlerMap = handlers.stream()
            .collect(Collectors.toMap(OAuthLoginHandler::getPlatform, Function.identity()));
    }

    public OAuthUser login(String platform, String code) {
        OAuthLoginHandler handler = handlerMap.get(platform);
        if (handler == null) {
            throw new UnsupportedOperationException("不支持的登录平台: " + platform);
        }
        return handler.login(code);
    }
}