netty 3.2.7高并发访问客户端丢包问题BUG

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于 2013-04-23 17:20:11 发布 · 2.1k 阅读

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#netty

在研究Netty 3.2.7源码时，发现NioServerSocketPipelineSink的BOSS线程可能引发高并发环境下客户端连接丢包。代码中清除了所有SelectionKey并仅接受一个连接。通过修改代码进行测试，证实了该问题。在后续的Netty 3.6.5版本中，服务器端的Boss代码进行了改进，根据SelectionKey数量处理客户端请求，可能已解决丢包问题。

最近在阅读netty（3.2.7）源码的时候，看到服务器端接受客户端连接代码的时候嗅到了一丝不和谐的气味，具体代码见：
org.jboss.netty.channel.socket.nio.NioServerSocketPipelineSink类里面的BOSS线程:

        public void run() {
            final Thread currentThread = Thread.currentThread();

            channel.shutdownLock.lock();
            try {
                for (;;) {
                    try {
                        if (selector.select(1000) > 0) {
                            selector.selectedKeys().clear();
                        }

                        SocketChannel acceptedSocket = channel.socket.accept();
                        if (acceptedSocket != null) {
                            registerAcceptedChannel(acceptedSocket, currentThread);
                        }
                    } catch (SocketTimeoutException e) {
                        // Thrown every second to get ClosedChannelException
                        // raised.
                    } catch (CancelledKeyException e) {
                        // Raised by accept() when the server socket was closed.
                    } catch (ClosedSelectorException e) {
                        // Raised by accept() when the server socket was closed.
                    } catch (ClosedChannelException e) {
                        // Closed as requested.
                        break;
                    } catch (Throwable e) {