如何有条件地链接多个Retrofit调用？

implementation 'io.reactivex.rxjava3:rxjava:3.x.x'
implementation 'io.reactivex.rxjava3:rxandroid:3.x.x'

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

public interface ApiService {
    @GET("endpoint1")
    Observable<ResponseData1> getData1();

    @GET("endpoint2")
    Observable<ResponseData2> getData2();
}

ApiService apiService = retrofit.create(ApiService.class);
Observable<ResponseData1> observable1 = apiService.getData1();
Observable<ResponseData2> observable2 = apiService.getData2();

observable1.flatMap(response1 -> {
    if (response1.isSuccess()) {
        return observable2;
    } else {
        return Observable.error(new Exception("Response 1 failed"));
    }
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(response2 -> {
    // 处理最终的响应结果
}, error -> {
    // 处理错误情况
});