Question

在改造2之前，有一种集中处理错误的方法 -

new retrofit.RestAdapter.Builder()
        .setEndpoint(apiUrl)
        .setLogLevel(retrofit.RestAdapter.LogLevel.FULL)
        .setErrorHandler(new CustomErrorHandler(ctx))

但现在在Retrofit 2中，RestAdapter已重命名为Retrofit且没有setErrorHandler()。有没有办法使用Retrofit.Builder()进行集中式错误处理？

Answer 1

您必须使用自定义服务成功或错误回调制作自定义CallAdapter。杰克沃顿已经成功了。您可以在github

的改造/样品中找到它

PS：不适用于2.2.0之前的版本

/*
 * Copyright (C) 2015 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.example.retrofit;

import java.io.IOException;
import java.lang.annotation.Annotation;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.concurrent.Executor;
import retrofit2.Call;
import retrofit2.CallAdapter;
import retrofit2.Callback;
import retrofit2.converter.gson.GsonConverterFactory;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.http.GET;

/**
 * A sample showing a custom {@link CallAdapter} which adapts the built-in {@link Call} to a custom
 * version whose callback has more granular methods.
 */
public final class ErrorHandlingAdapter {
  /** A callback which offers granular callbacks for various conditions. */
  interface MyCallback<T> {
    /** Called for [200, 300) responses. */
    void success(Response<T> response);
    /** Called for 401 responses. */
    void unauthenticated(Response<?> response);
    /** Called for [400, 500) responses, except 401. */
    void clientError(Response<?> response);
    /** Called for [500, 600) response. */
    void serverError(Response<?> response);
    /** Called for network errors while making the call. */
    void networkError(IOException e);
    /** Called for unexpected errors while making the call. */
    void unexpectedError(Throwable t);
  }

  interface MyCall<T> {
    void cancel();
    void enqueue(MyCallback<T> callback);
    MyCall<T> clone();

    // Left as an exercise for the reader...
    // TODO MyResponse<T> execute() throws MyHttpException;
  }

  public static class ErrorHandlingCallAdapterFactory extends CallAdapter.Factory {
    @Override public CallAdapter<?, ?> get(Type returnType, Annotation[] annotations,
        Retrofit retrofit) {
      if (getRawType(returnType) != MyCall.class) {
        return null;
      }
      if (!(returnType instanceof ParameterizedType)) {
        throw new IllegalStateException(
            "MyCall must have generic type (e.g., MyCall<ResponseBody>)");
      }
      Type responseType = getParameterUpperBound(0, (ParameterizedType) returnType);
      Executor callbackExecutor = retrofit.callbackExecutor();
      return new ErrorHandlingCallAdapter<>(responseType, callbackExecutor);
    }

    private static final class ErrorHandlingCallAdapter<R> implements CallAdapter<R, MyCall<R>> {
      private final Type responseType;
      private final Executor callbackExecutor;

      ErrorHandlingCallAdapter(Type responseType, Executor callbackExecutor) {
        this.responseType = responseType;
        this.callbackExecutor = callbackExecutor;
      }

      @Override public Type responseType() {
        return responseType;
      }

      @Override public MyCall<R> adapt(Call<R> call) {
        return new MyCallAdapter<>(call, callbackExecutor);
      }
    }
  }

  /** Adapts a {@link Call} to {@link MyCall}. */
  static class MyCallAdapter<T> implements MyCall<T> {
    private final Call<T> call;
    private final Executor callbackExecutor;

    MyCallAdapter(Call<T> call, Executor callbackExecutor) {
      this.call = call;
      this.callbackExecutor = callbackExecutor;
    }

    @Override public void cancel() {
      call.cancel();
    }

    @Override public void enqueue(final MyCallback<T> callback) {
      call.enqueue(new Callback<T>() {
        @Override public void onResponse(Call<T> call, Response<T> response) {
          // TODO if 'callbackExecutor' is not null, the 'callback' methods should be executed
          // on that executor by submitting a Runnable. This is left as an exercise for the reader.

          int code = response.code();
          if (code >= 200 && code < 300) {
            callback.success(response);
          } else if (code == 401) {
            callback.unauthenticated(response);
          } else if (code >= 400 && code < 500) {
            callback.clientError(response);
          } else if (code >= 500 && code < 600) {
            callback.serverError(response);
          } else {
            callback.unexpectedError(new RuntimeException("Unexpected response " + response));
          }
        }

        @Override public void onFailure(Call<T> call, Throwable t) {
          // TODO if 'callbackExecutor' is not null, the 'callback' methods should be executed
          // on that executor by submitting a Runnable. This is left as an exercise for the reader.

          if (t instanceof IOException) {
            callback.networkError((IOException) t);
          } else {
            callback.unexpectedError(t);
          }
        }
      });
    }

    @Override public MyCall<T> clone() {
      return new MyCallAdapter<>(call.clone(), callbackExecutor);
    }
  }
}

Answer 2

Retrofit 2.0移动了ErrorHandler并使用了包含两种方法的新Callback：

/** Successful HTTP response. */
public void onResponse(Response<T> response, Retrofit retrofit)````

/** Invoked when a network or unexpected exception occurred during the HTTP request. */
public void onFailure(Throwable t)

Retrofit2.x将收到onResponse中的所有HTTP响应，即使http代码不是2xx或3xx，在这里您需要检查onResponse方法中的响应状态代码并检查是否响应成功响应（通常为2xx或3xx）并进行正确的逻辑处理。

我已经升级了retrofit2.x，我的集中式错误处理解决方案是：创建一个使用onSuccess和onFailed两种方法扩展Retrofit.Callback的抽象类，onFailed不是抽象的，因为当业务逻辑失败时我总是执行相同的过程，并在请求成功时执行不同的操作。您可以参考示例代码here

然后，当你需要发送http请求时，你需要实现onSuccess方法，你也可以在某些情况下覆盖onFailed方法，正如我在项目中提到的，我在大多数情况下以相同的方式处理失败。您可以参考我使用retrofit2发送帖子请求的示例here。

希望这可以帮到你！

Answer 3

我使用了与Amir建议类似的解决方案，但我只是想知道这是否可以更容易实现。我尝试了以下方法：

model {
    android.sources {
        main {
            jni {
                dependencies {
                    project ":lib" 
                    // optional: 
                    // buildType "debug" productFlavor "flavor" linkage "static"
                }
            }
        }
    }
}

这样我就不需要传递Retrofit实例了。但是我错过了一些东西，因为错误主体未成功解析为StatusResponse。我不确定这在实践中意味着什么：

2.0.0-beta2的更改为回调的onResponse回调提供了Retrofit实例。提供Retrofit对象的边缘情况太多，以允许反序列化错误体。要适应此用例，请手动传递Retrofit响应或实现自定义CallAdapter.Factory自动执行此操作。

2.0.0-beta3

Answer 4

要集中处理特定于401的案件，以及使用新的auth令牌重试请求，请参阅此stack overflow answer。

集中式错误处理改造2？

4 个答案: