Question

我有一个在我的Web应用程序启动时启动的线程（contextInitialized）。所有这个线程都是，从套接字读取数据。

public void run() {
    while (!Thread.currentThread().isInterrupted() || !this.isInterrupted()
            || !stopped) {
        try {
            System.out.println("************polling..............");
            readData();
            Thread.sleep(300);
        } catch (InterruptedException e) {
            System.out.println("interrupted... ");
            Thread.currentThread().interrupt();
            break; //required?
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

   public void shutdown() {
    stopped = true;
    }
    // I know I'm blocking here.
    private void readData() {
          if (null == socket)
             throw new ConnectionException();
          if (inStream == null) {
             inStream = this.socket.getInputStream();
          }
          byte[] buff = new byte[length];
          int receiveLength = 0;
          do {
             try {
              receiveLength = inStream.read(buff, 0, length);
              } catch (Exception e) {
               e.printStackTrace();
              }

             } while (receiveLength <= 0);
       }

我在contextDestroyed中调用了interrupt（）方法，但这个线程无法停止，为什么呢？

    if (poller != null) {
        ((Poller) poller).shutdown();
        poller.interrupt();
                    // should I need to do this?
        while (poller.isAlive()) {
            ;
        }
    }

Answer 1

如果我这样做，我会用不同的库来做这件事：

真正的问题是readData内的这个循环：

do {
    try {
        receiveLength = inStream.read(buff, 0, length);
    } catch (Exception e) {
        e.printStackTrace();
    }
} while (receiveLength <= 0);

如果你在这里使用一个循环，它将继续读取，即使没有什么可读，而不是返回到具有延迟的外循环。摆脱循环。另外，将方法中的所有初始化移动到构造函数。

我将如何做到这一点：

class ConnectionReader implements TimerTask {

    InputStream inStream;
    byte[] buf;

    public ConnectionReader(Socket socket, int length){
        if (null == socket)
            throw new ConnectionException();
        if (inStream == null) {
            inStream = this.socket.getInputStream();
        }
        buf = new byte[length]
    }

    @Override
    public void run() {
        try {
            System.out.println("polling...");
            readData();
        } catch (InterruptedException e) {
            System.out.println("interrupted...");
            cancel()
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    private void readData() {
       try {
            receiveLength = inStream.read(buff, 0, length);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

要启动它，请将Timer设置为所需的300ms延迟：

TimerTask readTask = new ConnectionReader(this.socket, length);
new Timer().schedule(readTask,0,300);

要取消它，只需拨打readTask.cancel()。

停止Web容器内的线程

1 个答案: