OkHTTP框架

okHttp: OKHttp是Android版Http客户端。非常高效，支持SPDY、连接池、GZIP和 HTTP 缓存。默认情况下，OKHttp会自动处理常见的网络问题，像二次连接、SSL的握手问题。如果你的应用程序中集成了OKHttp，Retrofit默认会使用OKHttp处理其他网络层请求。
An HTTP & SPDY client for Android and Java applications  从Android4.4开始HttpURLConnection的底层实现采用的是okHttp.

使用要求:对于Android：2.3以上，对于Java:java7以上 两个模块： okhttp-urlconnection实现.HttpURLConnection API； okhttp-apache实现Apache HttpClient API. 依赖：okio(https://github.com/square/okio): Okio, which OkHttp uses for fast I/O and resizable buffers.

安装：

maven:

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<dependency>    <groupid>com.squareup.okhttp</groupid>    okhttp</artifactid>    <version> 2.3 . 0 </version> </dependency>

Gradle:

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1	compile 'com.squareup.okhttp:okhttp:2.3.0'

GET A URL

同步GET:

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private final OkHttpClient client = new OkHttpClient();   public void run() throws Exception {    Request request = new Request.Builder()        .url(http: //publicobject.com/helloworld.txt)        .build();      Response response = client.newCall(request).execute();    if (!response.isSuccessful()) throw new IOException(Unexpected code  + response);      Headers responseHeaders = response.headers();    for ( int i = 0 ; i < responseHeaders.size(); i++) {      System.out.println(responseHeaders.name(i) + :  + responseHeaders.value(i));    }      System.out.println(response.body().string()); }

异步GET:

在一个工作线程中下载文件，当响应可读时回调Callback接口。读取响应时会阻塞当前线程。OkHttp现阶段不提供异步api来接收响应体。

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private final OkHttpClient client = new OkHttpClient();   public void run() throws Exception {    Request request = new Request.Builder()        .url(http: //publicobject.com/helloworld.txt)        .build();      client.newCall(request).enqueue( new Callback() {      @Override public void onFailure(Request request, Throwable throwable) {        throwable.printStackTrace();      }        @Override public void onResponse(Response response) throws IOException {        if (!response.isSuccessful()) throw new IOException(Unexpected code  + response);          Headers responseHeaders = response.headers();        for ( int i = 0 ; i < responseHeaders.size(); i++) {          System.out.println(responseHeaders.name(i) + :  + responseHeaders.value(i));        }          System.out.println(response.body().string());      }    }); }

访问Header:

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private final OkHttpClient client = new OkHttpClient();   public void run() throws Exception {    Request request = new Request.Builder()        .url(https: //api.github.com/repos/square/okhttp/issues)        .header(User-Agent, OkHttp Headers.java)        .addHeader(Accept, application/json; q= 0.5 )        .addHeader(Accept, application/vnd.github.v3+json)        .build();      Response response = client.newCall(request).execute();    if (!response.isSuccessful()) throw new IOException(Unexpected code  + response);      System.out.println(Server:  + response.header(Server));    System.out.println(Date:  + response.header(Date));    System.out.println(Vary:  + response.headers(Vary)); }

Posting a String:

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public static final MediaType jsonReq      = MediaType.parse(application/json; charset=utf- 8 );   OkHttpClient client = new OkHttpClient();   String post(String url, String json) throws IOException {    RequestBody body = RequestBody.create(jsonReq, json);    Request request = new Request.Builder()        .url(url)        .post(body)        .build();    Response response = client.newCall(request).execute();    return response.body().string(); }