java - 在阻塞 ServerSocketChannel 上使用选择器

Question

选择器阻塞 ServerSocketChannel 的用例是什么时候？ 通常，选择器如何处理阻塞 channel ？

Answer 1

这是来自 SelectableChannel javadoc :

A channel must be placed into non-blocking mode before being registered with a selector, and may not be returned to blocking mode until it has been deregistered.

请参阅 register() 的 javadoc:https://docs.oracle.com/javase/7/docs/api/java/nio/channels/SelectableChannel.html#register(java.nio.channels.Selector,%20int)

public final SelectionKey register(Selector sel, int ops)

throw :

    IllegalBlockingModeException - If this channel is in blocking mode

这是 register() 的样子:

public final SelectionKey register(Selector sel, int ops,
                                   Object att)
    throws ClosedChannelException
{
    if (!isOpen())
        throw new ClosedChannelException();
    if ((ops & ~validOps()) != 0)
        throw new IllegalArgumentException();
    synchronized (regLock) {
        if (blocking)
            throw new IllegalBlockingModeException();
...