socketChannel 无法注册 Selector 对 OP_ACCEPT 进行监测

Question

public static void main(String[] args) throws IOException {

  Selector selector = Selector.open();
  SocketChannel socketChannel = SocketChannel.open();
  //The Channel must be in non-blocking mode to be used with a Selector.
    // This means that you cannot use FileChannel's with a Selector since FileChannel's cannot be switched into non-blocking mode.
    // Socket channels will work fine though.
  socketChannel.configureBlocking(false);
  //If you are interested in more than one event, OR the constants together, like this:
  int interestSet = SelectionKey.OP_ACCEPT;
  SelectionKey selectionKey = socketChannel.register(selector, interestSet);

  int interestSets = selectionKey.interestOps();
  boolean isInterestedInAccept = (interestSets & SelectionKey.OP_ACCEPT) == SelectionKey.OP_ACCEPT;
    System.out.println("flag: " + isInterestedInAccept);
}

报错： 

Connected to the target VM, address: '127.0.0.1:51931', transport: 'socket'<br /> Exception in thread "main" java.lang.IllegalArgumentException<br />     at java.nio.channels.spi.AbstractSelectableChannel.register(AbstractSelectableChannel.java:199)<br />     at java.nio.channels.SelectableChannel.register(SelectableChannel.java:280)<br />     at com.deodar.web.controller.nio.SelectorTest.main(SelectorTest.java:31)<br /> Disconnected from the target VM, address: '127.0.0.1:51931', transport: 'socket'

Process finished with exit code 1

源码： 

 

public final SelectionKey register(Selector sel, int ops,
                                   Object att)
    throws ClosedChannelException
{
    synchronized (regLock) {
        if (!isOpen())
            throw new ClosedChannelException();
        if ((ops & ~validOps()) != 0)
            throw new IllegalArgumentException();
        if (blocking)
            throw new IllegalBlockingModeException();
        SelectionKey k = findKey(sel);
        if (k != null) {
            k.interestOps(ops);
            k.attach(att);
        }
        if (k == null) {
            // New registration
            synchronized (keyLock) {
                if (!isOpen())
                    throw new ClosedChannelException();
                k = ((AbstractSelector)sel).register(this, ops, att);
                addKey(k);
            }
        }
        return k;
    }
}

Answer 1

不知道你这个问题是否已经解决, 如果还没有解决的话:

• 建议你看下这篇博客👉 ：向SocketChannel写入数据并读取返回数据

如果你已经解决了该问题, 非常希望你能够分享一下解决方案, 以帮助更多的人 ^-^