如何使用Retrofit2、Gson和Rx处理多种可能的响应类型

implementation 'com.squareup.retrofit2:retrofit:2.x.x'
implementation 'com.squareup.retrofit2:converter-gson:2.x.x'
implementation 'io.reactivex.rxjava2:rxjava:2.x.x'
implementation 'io.reactivex.rxjava2:rxandroid:2.x.x'

Retrofit retrofit = new Retrofit.Builder()
    .baseUrl("https://api.example.com/")
    .addConverterFactory(GsonConverterFactory.create())
    .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
    .build();

public interface ApiService {
    @GET("users/{user}")
    Observable<User> getUser(@Path("user") String user);

    @GET("users")
    Observable<List<User>> getUsers();
}

ApiService apiService = retrofit.create(ApiService.class);

apiService.getUser("john")
    .flatMap(user -> {
        // 处理用户响应
        return Observable.just(user);
    })
    .subscribeOn(Schedulers.io())
    .observeOn(AndroidSchedulers.mainThread())
    .subscribe(user -> {
        // 处理用户数据
    }, throwable -> {
        // 处理错误
    });

public class User {
    @SerializedName("name")
    private String name;

    // 其他字段和方法
}