【原创】「Android」Retrofit2.0+okhttp3

前言不搭后语：

自上次简书要求更新发布文章需要用户绑定微信和手机号，着实被恶心了一下下，也说过不再此处更新了。但现在想想，谁不是已经被扒的底裤都没了，这点隐私的抗争无非是给施暴者增加点情趣而已，穿上裤子，生活还得继续，文章还得继续写，此刻真香。

正题

一般设置超时时间的方法：

OkHttpClient.Builder builder = new OkHttpClient().newBuilder();
            builder.readTimeout(20, TimeUnit.SECONDS);
            builder.connectTimeout(10, TimeUnit.SECONDS).build();

Retrofit retrofit =new Retrofit.Builder().baseUrl("")
                            .client(client).build();
retrofit.create(ApiService.class);

但某些时候，我们需要针对单个的接口进行动态设置超时时间。网上能找到的答案基本都是拦截器+反射实现：

1. 创建一个新的OkHttpClient，重新设置超时时间。
2. 通过反射机制拿到对应的属性重新设置起时间值。

以上两种方法，第一种没试过，因为觉得不够优雅。
第二种网上的做法如下，是我根据网上看到的实现的：

/**
 * Created by ing on 2019/3/6
 * 动态设置接口请求超时时间
 */
public class DynamicTimeoutInterceptor implements Interceptor {
    @Override
    public Response intercept(Chain chain) throws IOException {
        Request oldRequest = chain.request();
        setDynamicTimeout(oldRequest,okhttpclient);//这里是你当前的okhttpclient对象
        Request newRequest = oldRequest.newBuilder()
                .method(oldRequest.method(), oldRequest.body())
                .url(oldRequest.url())
                .build();
        return chain.proceed(newRequest);
    }

    /**
     * 根据所需接口、进行动态设置网络超时时间
     *
     * @param oldRequest
//     * @param retrofit
     */
    private void setDynamicTimeout(Request oldRequest,OkHttpClient client) {
        final String questUrl = oldRequest.url().url().toString();
        try {
            //设置连接超时,注意混淆规则，避免字段被混淆
            boolean isCloseApi = questUrl.contains(PayApi.API_CLOSEORDER);
            boolean isPollingApi = questUrl.contains(PayApi.API_POLLING);
            if (isCloseApi||isPollingApi){
                Field readTimeoutField = client.getClass().getDeclaredField("readTimeout");
                readTimeoutField.setAccessible(true);
                //设置读写超时
                Field connectTimeoutField = client.getClass().getDeclaredField("connectTimeout");
                connectTimeoutField.setAccessible(true);
                //过滤接口，重新设置超时时间
                if (isCloseApi) {
                    connectTimeoutField.setInt(client, TimeOut.CLOSE_CONNECT);
                    readTimeoutField.setInt(client, TimeOut.CLOSE_READ);
                } else if (isPollingApi) {
                    readTimeoutField.setInt(client, TimeOut.POLLING_READ );
                }else {
                    readTimeoutField.setInt(client, TimeOut.DEFALT_READ );
                }
            }

        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (NoSuchFieldException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

以上方法测试无效，究其原因是因为反射拿到的属性是final的，所以即便拿到也无法修改，这里感谢评论里epitomizelu

解惑。
后来查看chain 接口内容，发现其内就已提供了对应的超时时间设置接口方法：

/**
 * Observes, modifies, and potentially short-circuits requests going out and the corresponding
 * responses coming back in. Typically interceptors add, remove, or transform headers on the request
 * or response.
 */
public interface Interceptor {
  Response intercept(Chain chain) throws IOException;

  interface Chain {
    Request request();

    Response proceed(Request request) throws IOException;

    /**
     * Returns the connection the request will be executed on. This is only available in the chains
     * of network interceptors; for application interceptors this is always null.
     */
    @Nullable Connection connection();

    Call call();

    int connectTimeoutMillis();

    Chain withConnectTimeout(int timeout, TimeUnit unit); //重点在这

    int readTimeoutMillis();

    Chain withReadTimeout(int timeout, TimeUnit unit);//重点在这

    int writeTimeoutMillis();

    Chain withWriteTimeout(int timeout, TimeUnit unit);//重点在这
  }
}

可以看到对应的三种超时时间都有提供，哦了，那我们就通过这个来设置一下，最终代码如下：

/**
 * Created by ing on 2019/3/6
 * 动态设置接口请求超时时间
 */
public class DynamicTimeoutInterceptor implements Interceptor {

    @Override
    public Response intercept(Chain chain) throws IOException {
        Request reequest = chain.request();
        String questUrl = reequest.url().toString();
        boolean isCloseApi = questUrl.contains(PayApi.API_CLOSEORDER);
        boolean isPollingApi = questUrl.contains(PayApi.API_POLLING);
        if (isCloseApi){
            return chain.withConnectTimeout(TimeOut.CLOSE_CONNECT,TimeUnit.SECONDS)
                    .withReadTimeout(TimeOut.CLOSE_READ,TimeUnit.SECONDS)
                    .proceed(reequest);
        }else if (isPollingApi){
            return chain.withReadTimeout(TimeOut.POLLING_READ,TimeUnit.SECONDS)
                    .proceed(reequest);
        }
        return chain.proceed(reequest);
    }
}

最后别忘了，将此拦截器添加上：
.addInterceptor(new DynamicTimeoutInterceptor())
然后测试 完美！！

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