okhttp连接池_okhttp源码分析

https://square.github.io/okhttp/

https://github.com/square/okhttp/

0 概述

okhttp是一个现代的网络请求框架

• Http/2 支持 所有访问同一个主机的Request都共用一个socket

• connection pool 连接池 减少请求延迟

• GZIP 压缩数据&＃xff0c;减少传输所用的带宽

• Response Cache 避免重复性的Request

1 使用

Get

OkHttpClient client &＃61; new OkHttpClient();

String run(String url) throws IOException {
Request request &＃61; new Request.Builder()
.url(url)
.build();

try (Response response &＃61; client.newCall(request).execute()) {
return response.body().string();
}
}


Post

public static final MediaType JSON
&＃61; MediaType.get("application/json; charset&＃61;utf-8");

OkHttpClient client &＃61; new OkHttpClient();

String post(String url, String json) throws IOException {
RequestBody body &＃61; RequestBody.create(json, JSON);
Request request &＃61; new Request.Builder()
.url(url)
.post(body)
.build();
try (Response response &＃61; client.newCall(request).execute()) {
return response.body().string();
}
}


Async

private final OkHttpClient client &＃61; new OkHttpClient();

public void run() throws Exception {
Request request &＃61; new Request.Builder()
.url("http://publicobject.com/helloworld.txt")
.build();

client.newCall(request).enqueue(new Callback() {
&＃64;Override public void onFailure(Call call, IOException e) {
e.printStackTrace();
}

&＃64;Override public void onResponse(Call call, Response response) throws IOException {
try (ResponseBody responseBody &＃61; response.body()) {
if (!response.isSuccessful()) throw new IOException("Unexpected code " &＃43; response);

Headers responseHeaders &＃61; response.headers();
for (int i &＃61; 0, size &＃61; responseHeaders.size(); i System.out.println(responseHeaders.name(i) &＃43; ": " &＃43; responseHeaders.value(i));
}

System.out.println(responseBody.string());
}
}
});
}


2 源码

2.0 请求过程

2.1 OkHttpClient

• dispatcher

• interceptors

• networkInterceptors

• connectionPool

• proxy

• newCall()

2.2 Call

• Response execute()

• enqueue(Callback responseCallback)

2.3 Request

• url

• method

• headers

• body

• tag

• cacheControl

2.4 Response

• request

• protocol

• code

• message

• headers

• body

• handshake

2.5 RealInterceptorChain

• interceptors

• transmitter

• index

• request

• call

• exchange

2.6 Interceptor

• Response intercept(Chain chain)

2.7 Cache

• DiskLruCache cache;

2.8 Connection

• Route route();

• Socket socket();

• Handshake handshake();

• Protocol protocol();

• connectSocket

• source

• sink

• connectionPool

3 架构

• 中间层

  • OKhttp 通过很多中间拦截器来对 Request  Response 进行加工

  • 实现了数据的  流式链式处理

• 生产者

• 分发器

  • 调度器 通过不同状态的  任务队列  来调度任务
  • readyCalls  runningCalls

• 消费者

• 缓存

• 拦截器

  • 类似责任链的效果&＃xff0c;链式处理&＃xff0c;链式返回