《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