RetrofitHelper库写在kotlin，将让你做API调用，使用几行代码，你可以使用不同的url，头和参数，在每个调用。

在你的应用类中添加多个url，如下所示:

class Application : Application() {

    override fun onCreate() {
    super.onCreate()

        retrofitClient = RetrofitClient.instance
                    //api url
                .setBaseUrl("https://reqres.in/")
                    //you can set multiple urls
        //                .setUrl("example","http://ngrok.io/api/")
                    //set timeouts
                .setConnectionTimeout(4)
                .setReadingTimeout(15)
                    //enable cache
                .enableCaching(this)
                    //add Headers
                .addHeader("Content-Type", "application/json")
                .addHeader("client", "android")
                .addHeader("language", Locale.getDefault().language)
                .addHeader("os", android.os.Build.VERSION.RELEASE)
            }

        companion object {
        lateinit var retrofitClient: RetrofitClient

        }
    }  

然后在调用中使用你需要的URL:

retrofitClient.Get<GetResponseModel>()
            //set base url
            .setBaseUrlKey("example")
            //set path
            .setPath("api/users/2")
            //set url params Key-Value or HashMap
            .setUrlParams("KEY","Value")
            .setResponseHandler(GetResponseModel::class.java,
                object : ResponseHandler<GetResponseModel>() {
                    override fun onSuccess(response: Response<GetResponseModel>) {
                        super.onSuccess(response)
                        //handle response
                    }
                }).run(this)

有关更多信息，请参阅文档

你可以在@Path注释上使用编码标志:

public interface APIService {
  @GET("{fullUrl}")
  Call<Users> getUsers(@Path(value = "fullUrl", encoded = true) String fullUrl);
}

这将防止用%2F替换/。 它救不了你?被%3F替换，因此您仍然不能传入动态查询字符串。

如果您已经设置了代码，并且不希望在可以更改的不同接口上进行更改，请使用此链接中描述的解决方案。 重点是更新URL并重新创建Retrofit构建器的changeApiBaseUrl方法。

public class ServiceGenerator {  
public static String apiBaseUrl = "http://futurestud.io/api";
private static Retrofit retrofit;

private static Retrofit.Builder builder =
        new Retrofit.Builder()
                .addConverterFactory(GsonConverterFactory.create())
                .baseUrl(apiBaseUrl);

private static OkHttpClient.Builder httpClient =
        new OkHttpClient.Builder();

// No need to instantiate this class.
private ServiceGenerator() {
}

public static void changeApiBaseUrl(String newApiBaseUrl) {
    apiBaseUrl = newApiBaseUrl;

    builder = new Retrofit.Builder()
                    .addConverterFactory(GsonConverterFactory.create())
                    .baseUrl(apiBaseUrl);
}

public static <S> S createService(Class<S> serviceClass, AccessToken token) {
    String authToken = token.getTokenType().concat(token.getAccessToken());
    return createService(serviceClass, authToken);
}

// more methods
// ...
}

你可以这样使用它:

public class DynamicBaseUrlActivity extends AppCompatActivity {

public static final String TAG = "CallInstances";
private Callback<ResponseBody> downloadCallback;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_file_upload);

    downloadCallback = new Callback<ResponseBody>() {
        @Override
        public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
            Log.d(TAG, "server contacted at: " + call.request().url());
        }

        @Override
        public void onFailure(Call<ResponseBody> call, Throwable t) {
            Log.d(TAG, "call failed against the url: " + call.request().url());
        }
    };

    // first request
    FileDownloadService downloadService = ServiceGenerator.create(FileDownloadService.class);
    Call<ResponseBody> originalCall = downloadService.downloadFileWithFixedUrl();
    originalCall.enqueue(downloadCallback);

    // change base url
    ServiceGenerator.changeApiBaseUrl("http://development.futurestud.io/api");

    // new request against new base url
    FileDownloadService newDownloadService = ServiceGenerator.create(FileDownloadService.class);
    Call<ResponseBody> newCall = newDownloadService.downloadFileWithFixedUrl();
    newCall.enqueue(downloadCallback);
    }
}

我只想替换url的一部分，有了这个解决方案，我不需要传递整个url，只是动态部分:

public interface APIService {

  @GET("users/{user_id}/playlists")
  Call<List<Playlist> getUserPlaylists(@Path(value = "user_id", encoded = true) String userId);
}

从Retrofit 2.0.0-beta2开始，如果你有一个服务从这个URL响应JSON: http://myhost/mypath

以下是无效的:

public interface ClientService {
    @GET("")
    Call<List<Client>> getClientList();
}

Retrofit retrofit = new Retrofit.Builder()
    .baseUrl("http://myhost/mypath")
    .addConverterFactory(GsonConverterFactory.create())
    .build();

ClientService service = retrofit.create(ClientService.class);

Response<List<Client>> response = service.getClientList().execute();

但这是可以的:

public interface ClientService {
    @GET
    Call<List<Client>> getClientList(@Url String anEmptyString);
}

Retrofit retrofit = new Retrofit.Builder()
    .baseUrl("http://myhost/mypath")
    .addConverterFactory(GsonConverterFactory.create())
    .build();

ClientService service = retrofit.create(ClientService.class);

Response<List<Client>> response = service.getClientList("").execute();

我认为你用错了。以下是更新日志的节选:

新:@Url参数注释允许为端点传递一个完整的URL。

所以你的界面应该是这样的:

public interface APIService {
    @GET
    Call<Users> getUsers(@Url String url);
}