《how tomcat work》 搬运工 charpter 4：Default Connector

Default Connector是Tomcat 4用的connector

Default Connector的工作是等待HTTP请求，创建request和response对象，然后传给container，然后container加载servlet来进行处理

Default Connector和charpter 3里的Connector区别是：

1、connector的HttpProcessor是同步的，要等到一个请求结束后才可以处理下一个请求。而Default Connector的HttpProcessor是在一个新的线程里进行的，也就是可以同时处理多个请求，而且HttpProcessor是从HttpProcessor poor里获取的

2、connecrot的HttpProcessor直接创建servlet来进行下一步处理，而Default Connector的HttpProcessor则通过Container来进行下一步处理。

Default Connector处理请求的流程:

1.等待请求

while (!stopped) {
    Socket socket = null;
     try {
            socket = serverSocket.accept();
     ...

2.获取HttpProcessor实例

　　　　　　　HttpProcessor processor = createProcessor();

3.assign socket

　　　　　　　　processor.assign(socket);

HttpProcessor的处理流程

1.run是等待await()方法来获取socket，

public void run() {
// Process requests until we receive a shutdown signal
    while (!stopped) {
        // Wait for the next socket to be assigned
        Socket socket = await();
        if (socket == null)
            continue;
        // Process the request from this socket
        try {
                process(socket);
        }
        catch (Throwable t) {
            log("process.invoke", t);
        }
        // Finish up this request
        connector.recycle(this);
    } 

// Tell threadStop() we have shut ourselves down successfully
    synchronized (threadSync) {
        threadSync.notifyAll();
    }
}

2.await()方法

private synchronized Socket await() {
    // Wait for the Connector to provide a new Socket
    while (!available)
    {
        try {
            wait();
        } catch (InterruptedException e) {
        }
    }
    // Notify the Connector that we have received this Socket
    Socket socket = this.socket;
    available = false;
    notifyAll();
    if ((debug >= 1) && (socket != null))
        log(" The incoming request has been awaited");
    return (socket);
}

3.assign()方法

synchronized void assign(Socket socket) {
    // Wait for the processor to get the previous socket
    while (available) {
        try {
            wait();
        } catch (InterruptedException e) {
        }
    }
    // Store the newly available Socket and notify our thread
    this.socket = socket;
    available = true;
    notifyAll();
}

await()和assign()来靠bool available来判别是否已经存入socket

其中，wait()是将线程变成等待，而notifyAll()则是将所有线程（await()）唤醒从而使await()返回socket

接下去就是container是事情了