OkHttpClient.Builder默認(rèn)參數(shù)

public Builder() {
    // dispatch。負(fù)責(zé)分配處理異步任務(wù)
    this.dispatcher = new Dispatcher();
    // 支持的協(xié)議鸟妙，默認(rèn)支持http2和http1.1
    this.protocols = OkHttpClient.DEFAULT_PROTOCOLS;
    // 指定socket鏈接配置昏鹃。默認(rèn)：MODERN_TLS和CLEARTEXT
    this.connectionSpecs = OkHttpClient.DEFAULT_CONNECTION_SPECS;
    // 監(jiān)聽http請(qǐng)求過(guò)程中涉及的各種事件完沪。包括：開始請(qǐng)求、dns解析開始/結(jié)束咐旧、鏈接開始等等。默認(rèn)是的Listener
    this.eventListenerFactory = EventListener.factory(EventListener.NONE);
    // 設(shè)置代理
    this.proxySelector = ProxySelector.getDefault();
    // 設(shè)置cookie
    this.cookieJar = CookieJar.NO_COOKIES;
    // 設(shè)置創(chuàng)建Socket鏈接的Factory
    this.socketFactory = SocketFactory.getDefault();
    // 驗(yàn)證域名和證書的域名是否匹配
    this.hostnameVerifier = OkHostnameVerifier.INSTANCE;
    // 設(shè)置信任的證書，不信任之外的證書沛善，默認(rèn)是空的
    this.certificatePinner = CertificatePinner.DEFAULT;
    // 與身份認(rèn)證有關(guān)。詳見：https://square.github.io/okhttp/3.x/okhttp/okhttp3/Authenticator.html
    this.proxyAuthenticator = Authenticator.NONE;
    // 與身份認(rèn)證有關(guān)塞祈。詳見：https://square.github.io/okhttp/3.x/okhttp/okhttp3/Authenticator.html
    this.authenticator = Authenticator.NONE;
    // 連接池-緩存鏈接和清理空閑的連接
    this.connectionPool = new ConnectionPool();
    // 域名解析
    this.dns = Dns.SYSTEM;
    // 是否支持ssl重定向
    this.followSslRedirects = true;
    // 是否支持重定向
    this.followRedirects = true;
    // 失敗后是否重試
    this.retryOnConnectionFailure = true;
    // 鏈接超時(shí)時(shí)間
    this.connectTimeout = 10000;
    // 讀超時(shí)時(shí)間
    this.readTimeout = 10000;
    // 寫超時(shí)時(shí)間
    this.writeTimeout = 10000;
    // ping的時(shí)間間隔路呜。如果使用WebSocket請(qǐng)求設(shè)置pingInterval，以保活
    this.pingInterval = 0;
}

Dispatcher-任務(wù)調(diào)度器

public final class Dispatcher {
    // 最大的異步請(qǐng)求數(shù)
    private int maxRequests = 64;
    // 單個(gè)host最大的請(qǐng)求數(shù)
    private int maxRequestsPerHost = 5;
    @Nullable
    private Runnable idleCallback;
    @Nullable
    // 執(zhí)行異步請(qǐng)求的線程池
    private ExecutorService executorService;
    // 尚未執(zhí)行的請(qǐng)求
    private final Deque<AsyncCall> readyAsyncCalls = new ArrayDeque();
    // 正在執(zhí)行的異步請(qǐng)求
    private final Deque<AsyncCall> runningAsyncCalls = new ArrayDeque();
    // 正在執(zhí)行的同步請(qǐng)求
    private final Deque<RealCall> runningSyncCalls = new ArrayDeque();
    // 設(shè)置異步線程池
    public Dispatcher(ExecutorService executorService) {
        this.executorService = executorService;
    }
    public Dispatcher() {
    }
    public synchronized ExecutorService executorService() {
        if (this.executorService == null) {
            // 默認(rèn)的異步線程池
            this.executorService = new ThreadPoolExecutor(0, 2147483647, 60L, TimeUnit.SECONDS, new SynchronousQueue(), Util.threadFactory("OkHttp Dispatcher", false));
        }
        return this.executorService;
    }
    // 異步任務(wù)胀葱，判斷異步任務(wù)數(shù)和單個(gè)host的請(qǐng)求數(shù)
    synchronized void enqueue(AsyncCall call) {
        if (this.runningAsyncCalls.size() < this.maxRequests && this.runningCallsForHost(call) < this.maxRequestsPerHost) {
            this.runningAsyncCalls.add(call);
            this.executorService().execute(call);
        } else {
            this.readyAsyncCalls.add(call);
        }
    }
}

ConnectionTool-緩存鏈接和清理空閑的連接

public final class ConnectionPool {
    // 負(fù)責(zé)清理空閑連接的線程池
    private static final Executor executor;
    // 最大空閑的連接數(shù)-默認(rèn)值：5
    private final int maxIdleConnections;
    // 最大的空閑時(shí)間-默認(rèn)值：5分鐘
    private final long keepAliveDurationNs;
    // 負(fù)責(zé)清理空閑連接的Runnable
    private final Runnable cleanupRunnable;
    // 所有的連接
    private final Deque<RealConnection> connections;
    final RouteDatabase routeDatabase;
    boolean cleanupRunning;
    
    public ConnectionPool() {
        this(5, 5L, TimeUnit.MINUTES);
    }
    
    public ConnectionPool(int maxIdleConnections, long keepAliveDuration, TimeUnit timeUnit) {
        ////
    }
    
    static {
        // 負(fù)責(zé)清理空閑連接的線程池
        executor = new ThreadPoolExecutor(0, 2147483647, 60L, TimeUnit.SECONDS, new SynchronousQueue(), Util.threadFactory("OkHttp ConnectionPool", true));
    }
}