集中式错误处理改造2？

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))

但是现在在Retrofit 2中,RestAdapter已经被重命名为,Retrofit而且没有setErrorHandler().有没有办法使用集中式错误处理Retrofit.Builder()？

Answer 1

您必须使用自定义服务成功或错误回调来创建自定义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 并使用了一个Callback包括两个方法的新方法：

/** 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)

onResponse即使 http 代码不是 2xx 或 3xx，Retrofit2.x 也会收到所有的 HTTP 响应，这里您需要检查方法中的响应状态码，onResponse并检查响应是否成功响应（通常为 2xx 或 3xx）并做对逻辑处理。

我已经升级了retrofit2.x，我关于集中错误处理的解决方案是：创建一个抽象类，扩展Retrofit.Callback有两个方法onSuccess和onFailed，onFailed不是抽象的，因为当业务逻辑失败时我总是做同样的过程并做请求成功时的不同之处。您可以在此处参考示例代码

然后，当您需要发送http请求时，您需要实现onSuccess方法，并且在某些情况下您也可以覆盖onFailed方法，正如我在我的项目中提到的，我在大多数情况下以相同的方式处理失败。您可以参考的例子在这里，我用retrofit2发送POST请求。

希望这可以帮到你！