public final OkHttpClient = new OkHttpClient.Builder()
  .addInterceptor(new HttpLoggingInterceptor())
  .cache(new Cache(cacheDir,cacheSize))
  .等等配置
  .build();

OkHttpClient agerClient = client.newBuilder()
  .readTimeout(500,TimeUnit.MILLSECONS)
  .build();

client.dispatcher().excurorService().shutdown()

client.connectionPool().evictAll()

client.cache().close();

// 獲取請求 url
public HttpUrl url();
// 獲取請求方法類型
public String method();
// 獲取請求頭
public Headers headers（）；
//獲取請求體
public RequestBody body();
// 獲取 tag
public Object tag();
// 返回緩存控制指令，永遠(yuǎn)不會(huì)是 null ，即使響應(yīng)不包含 Cache-Control 響應(yīng)頭
public CacheControl cacheControl();
// 是否是 https 請求
public boolean isHttps();
// Resquest{method=" ",url=" ",tag = " "}
public String toString();

// 創(chuàng)建客戶端
OkHttpClient client = new OkHttpclient();
// 建立請求體 
FormBody formBody = new FormBody.Builder()
                    .add("key0", "value0")
                    .add("key1","value1")
                    .build();
// 建立請求報(bào)文
Request request = new Request.Builder
                                .post(formBody)
                                .url("請求url")
                                .addHeader("Content-Type", "application/x-www-form-urlencoded")
  .addHeader("User-Agent", "PostmanRuntime/7.15.0")
  .addHeader("Accept", "*/*")
  .addHeader("Cache-Control", "no-cache")
  .addHeader("Postman-Token", "954bda0d-dbc2-4193-addf-a7631cab2cfa,af7c027c-a7ba-4560-98ae-3a2a473ab88a")
  .addHeader("Host", "39.106.24.148:8080")
  .addHeader("accept-encoding", "gzip, deflate")
  .addHeader("content-length", "133")
  .addHeader("Connection", "keep-alive")
  .addHeader("cache-control", "no-cache")
  .build();
// 發(fā)起請求
client.newCall(request).excute();

OkHttpClient client = new OkHttpClient();
MediaType mediaType = MediaType.parse("application/x-www-form-urlencoded");
RequestBody body = RequestBody.create(mediaType, "key0=value0&key1=value1");
Request request = new Request.Builder()
  .url("http://39.106.24.148:8080/test")
  .post(body)
  .addHeader("Content-Type", "application/x-www-form-urlencoded")
  .addHeader("User-Agent", "PostmanRuntime/7.15.0")
  .addHeader("Accept", "*/*")
  .addHeader("Cache-Control", "no-cache")
  .addHeader("Postman-Token", "954bda0d-dbc2-4193-addf-a7631cab2cfa,af7c027c-a7ba-4560-98ae-3a2a473ab88a")
  .addHeader("Host", "39.106.24.148:8080")
  .addHeader("accept-encoding", "gzip, deflate")
  .addHeader("content-length", "133")
  .addHeader("Connection", "keep-alive")
  .addHeader("cache-control", "no-cache")
  .build();
Response response = client.newCall(request).execute();

MediaType mediaType = MediaType.parse("image/png");
        RequestBody requestBody = new MultipartBody.Builder()
                    // 需要設(shè)置成表單形式否則無法上傳鍵值對參數(shù)
                .setType(MultipartBody.FORM)
                .addPart(Headers.of("Content-Disposition", "form-data;name=\"title\""),
                        RequestBody.create(null, "Square Logo"))
                .addPart(
                        Headers.of("Content-Disposition", "form-data;name=\"imge\""),
                        RequestBody.create(mediaType, new File("路徑/logo.png"))
                ).
                        build();
        Request request = new Request.Builder()
                .post(requestBody)
                .url("https://api.imgur.com/3/image")
                .build();
        try {
            mOkHttpClient.newCall(request).execute();
        } catch (IOException e) {
            e.printStackTrace();
        }

MediaType mediaType = MediaType.parse("image/png");
        RequestBody requestBody = new MultipartBody.Builder()
                 .setType(MultipartBody.FORM)
               .addFormDataPart("title","logo")
                .addFormDataPart("img","logo.png",RequestBody.create(mediaType,new File("路徑/logo.png")))
                .build();

// 比如這樣，就是這種固定的格式
"Content-Disposition","form-data;name=\"mFile\";filename=\"xxx.mp4\""

static RealCall newRealCall(OkHttpClient client, Request originalRequest, boolean forWebSocket) {
    // Safely publish the Call instance to the EventListener.
    RealCall call = new RealCall(client, originalRequest, forWebSocket);
    call.eventListener = client.eventListenerFactory().create(call);
    return call;
}

//異步請求同時(shí)存在的最大請求
private int maxRequests = 64;
//異步請求同一域名同時(shí)存在的最大請求
private int maxRequestsPerHost = 5;
//閑置任務(wù)(沒有請求時(shí)可執(zhí)行一些任務(wù)，由使用者設(shè)置)
private @Nullable Runnable idleCallback;
//異步請求使用的線程池
private @Nullable ExecutorService executorService;
//異步請求等待執(zhí)行隊(duì)列
private final Deque<AsyncCall> readyAsyncCalls = new ArrayDeque<>();
//異步請求正在執(zhí)行隊(duì)列
private final Deque<AsyncCall> runningAsyncCalls = new ArrayDeque<>();
//同步請求正在執(zhí)行隊(duì)列
private final Deque<RealCall> runningSyncCalls = new ArrayDeque<>();

synchronized void executed(RealCall call) {
	runningSyncCalls.add(call);
}

synchronized void enqueue(AsyncCall call) {
	if (runningAsyncCalls.size() < maxRequests && runningCallsForHost(call) < maxRequestsPerHost) 	  {
		runningAsyncCalls.add(call);
		executorService().execute(call);
	} else {
		readyAsyncCalls.add(call);
	}
}

//異步請求調(diào)用
void finished(AsyncCall call) {
	finished(runningAsyncCalls, call, true);
}
//同步請求調(diào)用
void finished(RealCall call) {
	finished(runningSyncCalls, call, false);
}
private <T> void finished(Deque<T> calls, T call, boolean promoteCalls) {
	int runningCallsCount;
	Runnable idleCallback;
	synchronized (this) {
        //不管異步還是同步，執(zhí)行完后都要從隊(duì)列移除(runningSyncCalls/runningAsyncCalls)
		if (!calls.remove(call)) throw new AssertionError("Call wasn't in-flight!");
		if (promoteCalls) promoteCalls();
        //異步任務(wù)和同步任務(wù)正在執(zhí)行的和
		runningCallsCount = runningCallsCount();
		idleCallback = this.idleCallback;
	}
	// 沒有任務(wù)執(zhí)行執(zhí)行閑置任務(wù)
	if (runningCallsCount == 0 && idleCallback != null) {
		idleCallback.run();
	}
}

private void promoteCalls() {
    //如果任務(wù)滿了直接返回
	if (runningAsyncCalls.size() >= maxRequests) return; 
    //沒有等待執(zhí)行的任務(wù)，返回
	if (readyAsyncCalls.isEmpty()) return; 
    //遍歷等待執(zhí)行隊(duì)列
	for (Iterator<AsyncCall> i = readyAsyncCalls.iterator(); i.hasNext(); ) {
		AsyncCall call = i.next();
        //等待任務(wù)想要執(zhí)行，還需要滿足：這個(gè)等待任務(wù)請求的Host不能已經(jīng)存在5個(gè)了
		if (runningCallsForHost(call) < maxRequestsPerHost) {
			i.remove();
			runningAsyncCalls.add(call);
			executorService().execute(call);
		}
		if (runningAsyncCalls.size() >= maxRequests) return; // Reached max capacity.
	}
}

@Override public Response execute() throws IOException {
    synchronized (this) {
      if (executed) throw new IllegalStateException("Already Executed");
      executed = true;
    }
    captureCallStackTrace();
    eventListener.callStart(this);
    try {
      //調(diào)用分發(fā)器
      client.dispatcher().executed(this);
      //執(zhí)行請求
      Response result = getResponseWithInterceptorChain();
      if (result == null) throw new IOException("Canceled");
      return result;
    } catch (IOException e) {
      eventListener.callFailed(this, e);
      throw e;
    } finally {
      //請求完成
      client.dispatcher().finished(this);
    }
}

@Override
public void enqueue(Callback responseCallback) {
	synchronized (this) {
		if (executed) throw new IllegalStateException("Already Executed");
		executed = true;
	}
	captureCallStackTrace();
	eventListener.callStart(this);
    //調(diào)用分發(fā)器
	client.dispatcher().enqueue(new AsyncCall(responseCallback));
}

final class AsyncCall extends NamedRunnable {
	private final Callback responseCallback;
	AsyncCall(Callback responseCallback) {
		super("OkHttp %s", redactedUrl());
		this.responseCallback = responseCallback;
	}
    //線程池執(zhí)行
	@Override
	protected void execute() {
	 boolean signalledCallback = false;
      try {
        Response response = getResponseWithInterceptorChain();
       //.......
      } catch (IOException e) {
       //......
      } finally {
        //請求完成
        client.dispatcher().finished(this);
      }
    }
}
public abstract class NamedRunnable implements Runnable {
    protected final String name;
    public NamedRunnable(String format, Object... args) {
        this.name = Util.format(format, args);
    }
    @Override
    public final void run() {
        String oldName = Thread.currentThread().getName();
        Thread.currentThread().setName(name);
        try {
            execute();
        } finally {
            Thread.currentThread().setName(oldName);
        }
    }
    protected abstract void execute();
}

public synchronized ExecutorService executorService() {
    if (executorService == null) {
      executorService = new ThreadPoolExecutor(
          					0,   				//核心線程
                            Integer.MAX_VALUE,  //最大線程
                            60,					//空閑線程閑置時(shí)間
                            TimeUnit.SECONDS,	//閑置時(shí)間單位
                            new SynchronousQueue<Runnable>(), //線程等待隊(duì)列
                            Util.threadFactory("OkHttp Dispatcher", false) //線程創(chuàng)建工廠
      );
    }
    return executorService;
}