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=============================我是华丽丽的分割线=========================================

方法

同步GET

  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
在工作者线程（子线程）中下载一个文件，并且响应体可读时调用回调方法。当响应体的头文件准备完毕后，回调方法才会被执行。读取响应体可能一直阻塞。目前OkHttp并没有提供异步APIs，让我们分开接收响应体。
  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(Call call, IOException e) {        e.printStackTrace();      }      @Override public void onResponse(Call call, Response response) throws IOException {        if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);        Headers responseHeaders = response.headers();        for (int i = 0, size = responseHeaders.size(); i < size; i++) {          System.out.println(responseHeaders.name(i) + ": " + responseHeaders.value(i));        }        System.out.println(response.body().string());      }    });  }
获取头文件
典型的HTTP头文件有点像Map<String,String>：每一个字段都有一个值或者没有值。但是一些头文件允许多个值，像Guava的Multimap。举个例子，对HTTP的响应体来说，它的协议规范（It's legal and comon）是支持多种Vary头文件的。OkHttp的APIs尝试兼容这两种情况。当读取响应体的头文件的时候，header(name)适用于name和value一对一的情况。如果name和value是一对多的关系，那么新的值会覆盖之前的值。使用方法addHeader(name,value)添加一个头文件（header），则不会移除已经存在的头文件（headers）。当读取响应体的头文件的时候，header(name)方法返回的是最新的命名值。通常情况下这也是唯一的结果。如果没有值，那么header(name)就会返回null。想要把一个字段的所有值读取为一个集合的话，就需要使用headers(name)。为了访问所有的头文件，需要使用支持角标索引的Headers类。
  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"));  }
POST发送字符串
使用HTTP的POST方式发送一个请求体到服务器。这个例子将一个Markdown文档通过post方式发送到将Markdown读取为HTML格式的web服务器。因为全部请求体同时存在于内存中，在使用这个API的时候，避免发送太大（大于1MiB）的文档。
  public static final MediaType MEDIA_TYPE_MARKDOWN      = MediaType.parse("text/x-markdown; charset=utf-8");  private final OkHttpClient client = new OkHttpClient();  public void run() throws Exception {    String postBody = ""        + "Releases/n"        + "--------/n"        + "/n"        + " * _1.0_ May 6, 2013/n"        + " * _1.1_ June 15, 2013/n"        + " * _1.2_ August 11, 2013/n";    Request request = new Request.Builder()        .url("https://api.github.com/markdown/raw")        .post(RequestBody.create(MEDIA_TYPE_MARKDOWN, postBody))        .build();    Response response = client.newCall(request).execute();    if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);    System.out.println(response.body().string());  }
POST发送流
这里我们通过POST方法以流的方式发送请求体。请求体的内容边写边生成（is generated as it's being written）。在这个例子中，流直接放入Okio的缓冲（库）。你的程序可能更倾向于使用OutputSteam，你可以通过BufferedSink.outputStream()获取到。
public static final MediaType MEDIA_TYPE_MARKDOWN      = MediaType.parse("text/x-markdown; charset=utf-8");  private final OkHttpClient client = new OkHttpClient();  public void run() throws Exception {    RequestBody requestBody = new RequestBody() {      @Override public MediaType contentType() {        return MEDIA_TYPE_MARKDOWN;      }      @Override public void writeTo(BufferedSink sink) throws IOException {        sink.writeUtf8("Numbers/n");        sink.writeUtf8("-------/n");        for (int i = 2; i <= 997; i++) {          sink.writeUtf8(String.format(" * %s = %s/n", i, factor(i)));        }      }      private String factor(int n) {        for (int i = 2; i < n; i++) {          int x = n / i;          if (x * i == n) return factor(x) + " × " + i;        }        return Integer.toString(n);      }    };    Request request = new Request.Builder()        .url("https://api.github.com/markdown/raw")        .post(requestBody)        .build();    Response response = client.newCall(request).execute();    if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);    System.out.println(response.body().string());  }
POST发送一个文件
将文件作为请求体，即可实现。
  public static final MediaType MEDIA_TYPE_MARKDOWN      = MediaType.parse("text/x-markdown; charset=utf-8");  private final OkHttpClient client = new OkHttpClient();  public void run() throws Exception {    File file = new File("README.md");    Request request = new Request.Builder()        .url("https://api.github.com/markdown/raw")        .post(RequestBody.create(MEDIA_TYPE_MARKDOWN, file))        .build();    Response response = client.newCall(request).execute();    if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);    System.out.println(response.body().string());  }
POST发送表格参数
使用FormBody.Builder创建请求体，就像HTML中的<form>标签一样。键和值使用HTML兼容形式的URL编码进行编码。
  private final OkHttpClient client = new OkHttpClient();  public void run() throws Exception {    RequestBody formBody = new FormBody.Builder()        .add("search", "Jurassic Park")        .build();    Request request = new Request.Builder()        .url("https://en.wikipedia.org/w/index.php")        .post(formBody)        .build();    Response response = client.newCall(request).execute();    if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);    System.out.println(response.body().string());  }
POST发布多部分请求
MultipartBody.Builder可以构建多个与HTML文件上传表单兼容的请求体。多个请求体中的每一部分本身就是一个请求体，并且能够钉子它们自己的头文件。如果出现这种情况，那么这些头文件应该描述部分请求体，比如说它的Content-Disposition。当Content-Length和Content-Type头文件可以获取到的时候，它们会被自动添加进来。
  private static final String IMGUR_CLIENT_ID = "...";  private static final MediaType MEDIA_TYPE_PNG = MediaType.parse("image/png");  private final OkHttpClient client = new OkHttpClient();  public void run() throws Exception {    // Use the imgur image upload API as documented at https://api.imgur.com/endpoints/image    RequestBody requestBody = new MultipartBody.Builder()        .setType(MultipartBody.FORM)        .addFormDataPart("title", "Square Logo")        .addFormDataPart("image", "logo-square.png",            RequestBody.create(MEDIA_TYPE_PNG, new File("website/static/logo-square.png")))        .build();    Request request = new Request.Builder()        .header("Authorization", "Client-ID " + IMGUR_CLIENT_ID)        .url("https://api.imgur.com/3/image")        .post(requestBody)        .build();    Response response = client.newCall(request).execute();    if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);    System.out.println(response.body().string());  }
使用Gson解析JSON格式的响应体
Gson是一款转化JSON和Java对象的优秀API。在这里，我们用它来将一个JSON格式的响应体解码（参考Github上API）。这里要注意，当解码响应体的时候，ResponseBody.charStream()使用了Content-Type响应体头文件来决定使用哪个字符集。默认是UTF-8.
  private final OkHttpClient client = new OkHttpClient();  private final Gson gson = new Gson();  public void run() throws Exception {    Request request = new Request.Builder()        .url("https://api.github.com/gists/c2a7c39532239ff261be")        .build();    Response response = client.newCall(request).execute();    if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);    Gist gist = gson.fromJson(response.body().charStream(), Gist.class);    for (Map.Entry<String, GistFile> entry : gist.files.entrySet()) {      System.out.println(entry.getKey());      System.out.println(entry.getValue().content);    }  }  static class Gist {    Map<String, GistFile> files;  }  static class GistFile {    String content;  }
响应体缓存
为了缓存响应体，你需要指定可以写入、读取的缓存路径，并且限定缓存大小。缓存路径应该是私有的，以保证不受信任的应用不能读取到它的内容。对于同一个缓存路径，同时拥有多个入口的做法是错误的。大多数的应用地方应该只调用new OkHttp()一次，配置缓存，在每个地方使用同一个实例。否则两个缓存实例会相互冲突，使响应体缓存失效，并且应用有可能崩溃。对于所有的配置，响应体缓存使用HTTP头文件。你可以自己添加头文件，比如说Cache-Control:max-stale=3600，覆盖OkHttp的默认缓存。服务器配置了响应体应当被缓存多久，存放在响应体的头文件中，比如Cache-Control:max-age=9600。当然，有些时候我们需要强制使用缓存的响应体，或者强制使用网络响应体，抑或是强制使用可选Get验证的网络响应体。
  private final OkHttpClient client;  public CacheResponse(File cacheDirectory) throws Exception {    int cacheSize = 10 * 1024 * 1024; // 10 MiB    Cache cache = new Cache(cacheDirectory, cacheSize);    client = new OkHttpClient.Builder()        .cache(cache)        .build();  }  public void run() throws Exception {    Request request = new Request.Builder()        .url("http://publicobject.com/helloworld.txt")        .build();    Response response1 = client.newCall(request).execute();    if (!response1.isSuccessful()) throw new IOException("Unexpected code " + response1);    String response1Body = response1.body().string();    System.out.println("Response 1 response:          " + response1);    System.out.println("Response 1 cache response:    " + response1.cacheResponse());    System.out.println("Response 1 network response:  " + response1.networkResponse());    Response response2 = client.newCall(request).execute();    if (!response2.isSuccessful()) throw new IOException("Unexpected code " + response2);    String response2Body = response2.body().string();    System.out.println("Response 2 response:          " + response2);    System.out.println("Response 2 cache response:    " + response2.cacheResponse());    System.out.println("Response 2 network response:  " + response2.networkResponse());    System.out.println("Response 2 equals Response 1? " + response1Body.equals(response2Body));  }为了防止使用缓存中的响应体，可以使用CacheControl.FORCE_NETWORK.为了防止使用网络响应体，可以使用CacheControl.FORCE_CACHE.警告：如果你使用FORCE_CACHE，并且响应体需要网络，PkHttp可能会返回504（不可满足的请求）的响应。
取消一个调用
使用Call.cancel()，可以立即停止一个进行中的调用。如果一个线程正在写入一个请求或者读取一个响应体，就会接收到IOException。当某个调用失去其必要性的时候，使用这个方法可以节省网络；举个例子，当你的用户离开某个应用层的。同步和异步的调用都可以被取消。
  private final ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);  private final OkHttpClient client = new OkHttpClient();  public void run() throws Exception {    Request request = new Request.Builder()        .url("http://httpbin.org/delay/2") // This URL is served with a 2 second delay.        .build();    final long startNanos = System.nanoTime();    final Call call = client.newCall(request);    // Schedule a job to cancel the call in 1 second.    executor.schedule(new Runnable() {      @Override public void run() {        System.out.printf("%.2f Canceling call.%n", (System.nanoTime() - startNanos) / 1e9f);        call.cancel();        System.out.printf("%.2f Canceled call.%n", (System.nanoTime() - startNanos) / 1e9f);      }    }, 1, TimeUnit.SECONDS);    try {      System.out.printf("%.2f Executing call.%n", (System.nanoTime() - startNanos) / 1e9f);      Response response = call.execute();      System.out.printf("%.2f Call was expected to fail, but completed: %s%n",          (System.nanoTime() - startNanos) / 1e9f, response);    } catch (IOException e) {      System.out.printf("%.2f Call failed as expected: %s%n",          (System.nanoTime() - startNanos) / 1e9f, e);    }  }
超时
当请求无法访问的时候，使用超时去结束一个调用。网络分区取决于客户端的连通性问题，服务器的稳定性问题，或者二者之间的任意问题。OkHttp支持连接、读取和写入超时。
 private final OkHttpClient client;  public ConfigureTimeouts() throws Exception {    client = new OkHttpClient.Builder()        .connectTimeout(10, TimeUnit.SECONDS)        .writeTimeout(10, TimeUnit.SECONDS)        .readTimeout(30, TimeUnit.SECONDS)        .build();  }  public void run() throws Exception {    Request request = new Request.Builder()        .url("http://httpbin.org/delay/2") // This URL is served with a 2 second delay.        .build();    Response response = client.newCall(request).execute();    System.out.println("Response completed: " + response);  }
每一个调用的配置
所有的HTTP客户端配置都在OkHttpClient中，包括代理设置，超时和缓存。当你需要单独设置某一个调用的配置，调用OkHttpClient.newBuilder()即可。该方法将会返回Builder实例，与原来的client共用同一个连接池、调度器和配置。在下面的例子中，我们设置了超时分别为500ms和3000ms的请求
  private final OkHttpClient client = new OkHttpClient();  public void run() throws Exception {    Request request = new Request.Builder()        .url("http://httpbin.org/delay/1") // This URL is served with a 1 second delay.        .build();    try {      // Copy to customize OkHttp for this request.      OkHttpClient copy = client.newBuilder()          .readTimeout(500, TimeUnit.MILLISECONDS)          .build();      Response response = copy.newCall(request).execute();      System.out.println("Response 1 succeeded: " + response);    } catch (IOException e) {      System.out.println("Response 1 failed: " + e);    }    try {      // Copy to customize OkHttp for this request.      OkHttpClient copy = client.newBuilder()          .readTimeout(3000, TimeUnit.MILLISECONDS)          .build();      Response response = copy.newCall(request).execute();      System.out.println("Response 2 succeeded: " + response);    } catch (IOException e) {      System.out.println("Response 2 failed: " + e);    }  }
处理认证
OkHttp可以自动重试非认证请求。当一个响应码是401（没有认证）的时候，认证者请求提供认证证书。实现的时候，需要创建一个新的请求，其中要包括缺失的认证证书。如果没有可获取的认证证书，那么将跳过重试，并返回null。使用Response.challenges()获取任何认证（authentication challenges）的规范和域。当填满一个基本的challenge，使用Credentials.basic(username,passWord)来编码请求
  private final OkHttpClient client;  public Authenticate() {    client = new OkHttpClient.Builder()        .authenticator(new Authenticator() {          @Override public Request authenticate(Route route, Response response) throws IOException {            System.out.println("Authenticating for response: " + response);            System.out.println("Challenges: " + response.challenges());            String credential = Credentials.basic("jesse", "password1");            return response.request().newBuilder()                .header("Authorization", credential)                .build();          }        })        .build();  }  public void run() throws Exception {    Request request = new Request.Builder()        .url("http://publicobject.com/secrets/hellosecret.txt")        .build();    Response response = client.newCall(request).execute();    if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);    System.out.println(response.body().string());  }当认证不起作用的时候，为了避免发生多次尝试，你可以通过返回null的方式放弃。举个例子，当这些已存在的认证证书已经尝试过了，你可能想要跳过重试。
if (credential.equals(response.request().header("Authorization"))) {    return null; // If we already failed with these credentials, don't retry.   }当达到应用设置的尝试上限的时候，你也需要跳过重试。 
if (responseCount(response) >= 3) {    return null; // If we've failed 3 times, give up.  }上面的代码依赖于responseCount()方法：
  private int responseCount(Response response) {    int result = 1;    while ((response = response.priorResponse()) != null) {      result++;    }    return result;  }（翻译的有点着急，我汪在旁边撒娇卖萌不止< -- >抽空再次修改）==========================================我是华丽丽的分割线=======================================================（此处应当有我汪的照片，来日一并补上）