okhttp之自定义Interceptor：请求失败切换IP重试拦截器

尊重他人的劳动成果，转载请标明出处：https://www.geek-share.com/detail/2682079571.html， 本文出自:【gengqiquan的博客】经过一段时间的挣扎，终于把新公司项目的网络框架换成了retrofit，由于项目是有失败重试和重定向需求的，所以需要在新的网络框架上增加这个功能，大家都知道retrofit的网络请求部分是基于okhttp的。这个时候可爱的Interceptor设计就提现出他的好处了，不需要修改其他的代码，直接增加一个拦截器就OK了实现一个拦截器继承Interceptor（2.0到3.0之前的版本）

public class RetryAndChangeIpInterceptor implements Interceptor {
String FirstIP;
String SecondIP;
int RetryCount;

public RetryAndChangeIpInterceptor(String firsrIP, String secondIP, int tryCount) {
FirstIP = firsrIP;
SecondIP = secondIP;
RetryCount = tryCount;
}

public RetryAndChangeIpInterceptor(String firsrIP, String secondIP) {
FirstIP = firsrIP;
SecondIP = secondIP;
RetryCount = 3;
}

@Override
public Response intercept(Chain chain) throws IOException {
Request request = chain.request();
// try the request
Response response = chain.proceed(request);
int tryCount = 0;
while (!response.isSuccessful() && tryCount <= RetryCount) {
String url = request.url().toString();
if (!Util.checkNULL(FirstIP) && !Util.checkNULL(SecondIP)) {//重定向
if (url.contains(FirstIP)) {
url = url.replace(FirstIP, SecondIP);
} else if (url.contains(SecondIP)) {
url = url.replace(SecondIP, FirstIP);
}
Request newRequest = response.request().newBuilder().url(url).build();
Log.d("intercept", "Request is not successful - " + tryCount);
tryCount++;
// retry the request
response = chain.proceed(newRequest);
} else {
response = chain.proceed(request);
}
}
return response;
}
}

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3.0及以上版本（取消了httpEngine，采用了纯拦截器递归调用机制）

package com.sunshine.retrofit.interceptor;

import android.util.Log;

import java.io.IOException;
import java.util.List;

import okhttp3.Interceptor;
import okhttp3.Request;
import okhttp3.Response;

/**
* Created by 耿 on 2016/8/12.
*/
public class RetryAndChangeIpInterceptor implements Interceptor {
int RetryCount = 3;
String FirstIP;
List<String> SERVERS;

public RetryAndChangeIpInterceptor(String firsrIP, List<String> sERVERS) {
FirstIP = firsrIP;
SERVERS = sERVERS;
RetryCount = 3;
}

public RetryAndChangeIpInterceptor(String firsrIP, List<String> sERVERS, int tryCount) {
FirstIP = firsrIP;
SERVERS = sERVERS;
RetryCount = tryCount;
}

@Override
public Response intercept(Chain chain) throws IOException {
Request request = chain.request();
// try the request
Response response = doRequest(chain, request);
int tryCount = 0;
String url = request.url().toString();
while (response == null && tryCount <= RetryCount) {
url = switchServer(url);
Request newRequest = request.newBuilder().url(url).build();
Log.d("intercept", "Request is not successful - " + tryCount);
tryCount++;
// retry the request
response = doRequest(chain, newRequest);
}
if (response == null) {
throw new IOException();
}
return response;
}

private Response doRequest(Chain chain, Request request) {
Response response = null;
try {
response = chain.proceed(request);
} catch (Exception e) {
}
return response;
}

private String switchServer(String url) {
String newUrlString = url;
if (url.contains(FirstIP)) {
for (String server : SERVERS) {
if (!FirstIP.equals(server)) {
newUrlString = url.replace(FirstIP, server);
break;
}
}
} else {
for (String server : SERVERS) {
if (url.contains(server)) {
newUrlString = url.replace(server, FirstIP);
break;
}
}
}
return newUrlString;
}

}

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配置OkHttpClient

OkHttpClient client = new OkHttpClient.Builder()
.addInterceptor(new RetryAndChangeIpInterceptor(BASE_URL, SecondIP))//添加失败重试及重定向拦截器

.retryOnConnectionFailure(true)//允许失败重试
.connectTimeout(8, TimeUnit.SECONDS)
.readTimeout(5, TimeUnit.SECONDS)
.writeTimeout(5, TimeUnit.SECONDS)
.build();

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