同步请求

public class GetExample {  OkHttpClient client = new OkHttpClient();  String run(String url) throws IOException {    //包含请求头，url,请求参数    Request request = new Request.Builder()        .url(url)        .build();    //newcall方法创建了realcall    try (Response response = client.newCall(request).execute()) {      return response.body().string();    }  }  public static void main(String[] args) throws IOException {    GetExample example = new GetExample();    String response = example.run("https://raw.github.com/square/okhttp/master/README.md");    System.out.println(response);  }}

RealCall 的execute方法

   @Override    public Response execute() throws IOException {        synchronized (this) {        //同一个RealCall 只能同时执行一个请求            if (executed) throw new IllegalStateException("Already Executed");            executed = true;        }        captureCallStackTrace();        timeout.enter();        eventListener.callStart(this);        try {        //将请求添加到dispatcher分发器里            client.dispatcher().executed(this);            //通过拦截链获取最后的结果，拦截链设计的很巧妙            Response result = getResponseWithInterceptorChain();            if (result == null) throw new IOException("Canceled");            return result;        } catch (IOException e) {            e = timeoutExit(e);            eventListener.callFailed(this, e);            throw e;        } finally {        //在分发器里将本次请求去掉            client.dispatcher().finished(this);        }    }

异步请求

client.newCall(request).enqueue(new Callback() {            @Override            public void onFailure(Call call, IOException e) {            }            @Override            public void onResponse(Call call, Response response) throws IOException {            }        });

enqueue源码

@Override    public void enqueue(Callback responseCallback) {        synchronized (this) {            if (executed) throw new IllegalStateException("Already Executed");            executed = true;        }        captureCallStackTrace();        eventListener.callStart(this);        //分发器里添加该请求        client.dispatcher().enqueue(new AsyncCall(responseCallback));    }

查看dispatcher的enqueue

/** Ready async calls in the order they'll be run. */  //准备执行异步的请求  private final Deque<AsyncCall> readyAsyncCalls = new ArrayDeque<>();  /** Running asynchronous calls. Includes canceled calls that haven't finished yet. */  //正在执行的异步请求  private final Deque<AsyncCall> runningAsyncCalls = new ArrayDeque<>();  /** Running synchronous calls. Includes canceled calls that haven't finished yet. */  private final Deque<RealCall> runningSyncCalls = new ArrayDeque<>();    void enqueue(AsyncCall call) {    synchronized (this) {     //将该请求放到准备执行的异步请求栈里      readyAsyncCalls.add(call);      // Mutate the AsyncCall so that it shares the AtomicInteger of an existing running call to      // the same host.      if (!call.get().forWebSocket) {        AsyncCall existingCall = findExistingCallWithHost(call.host());        if (existingCall != null) call.reuseCallsPerHostFrom(existingCall);      }    }    promoteAndExecute();  }

private boolean promoteAndExecute() {    assert (!Thread.holdsLock(this));    List<AsyncCall> executableCalls = new ArrayList<>();    boolean isRunning;    synchronized (this) {      for (Iterator<AsyncCall> i = readyAsyncCalls.iterator(); i.hasNext(); ) {        AsyncCall asyncCall = i.next();//根据最大请求数，将准备执行的网络请求添加到正在执行的网络请求栈中        if (runningAsyncCalls.size() >= maxRequests) break; // Max capacity.        if (asyncCall.callsPerHost().get() >= maxRequestsPerHost) continue; // Host max capacity.        i.remove();        asyncCall.callsPerHost().incrementAndGet();        executableCalls.add(asyncCall);        runningAsyncCalls.add(asyncCall);      }      isRunning = runningCallsCount() > 0;    }    for (int i = 0, size = executableCalls.size(); i < size; i++) {      AsyncCall asyncCall = executableCalls.get(i);      asyncCall.executeOn(executorService());    }    return isRunning;  }

dispatcher类将多个网络请求进行分发管理。

okhttp源码学习分析一

okhttp源码学习分析一

同步请求

RealCall 的execute方法

异步请求

enqueue源码

更多相关文章

随机推荐