Netty 选择器注册通道为 0

Question

最近看了netty的源码。 对于频道注册，我阅读了以下代码：

文件名： AbstractNioChannel.java

@Override
protected void doRegister() throws Exception {
    boolean selected = false;
    for (;;) {
        try {
            selectionKey = javaChannel().register(eventLoop().unwrappedSelector(), 0, this);
            return;
        } catch (CancelledKeyException e) {
            if (!selected) {
                // Force the Selector to select now as the "canceled" SelectionKey may still be
                // cached and not removed because no Select.select(..) operation was called yet.
                eventLoop().selectNow();
                selected = true;
            } else {
                // We forced a select operation on the selector before but the SelectionKey is still cached
                // for whatever reason. JDK bug ?
                throw e;
            }
        }
    }
}

那么，对于使用频道的兴趣键 0 注册的频道来说，这意味着什么？

Answer 1

这意味着它已注册并且仅通知错误。