Netty 中 IOException Connection reset by peer 与 java.nio.channels.ClosedChannelException null.doc

Netty 中 IOException: Connection reset by peer 与 java.nio.channels.ClosedChannelException: null 最近发现系统中出现了很多 IOException: Connection reset by peer 与 ClosedChannelException: null 深入看了看代码, 做了些测试, 发现 Connection reset 会在客户端不知道 channel 被关闭的情况下, 触发了 eventloop 的 unsafe.read() 操作抛出 而 ClosedChannelException 一般是由 Netty 主动抛出的, 在 AbstractChannel 以及 SSLHandler 里都可以看到 ClosedChannel 相关的代码 AbstractChannel? static final ClosedChannelException CLOSED_CHANNEL_EXCEPTION = new ClosedChannelException(); ... static { CLOSED_CHANNEL_EXCEPTION.setStackTrace(EmptyArrays.EMPTY_STACK_TRACE); NOT_YET_CONNECTED_EXCEPTION.setStackTrace(EmptyArrays.EMPTY_STACK_TRACE); } ... @Override public void write(Object msg, ChannelPromise promise) { ChannelOutboundBuffer outboundBuffer = this.outboundBuffer; if (outboundBuffer == null) { // If the outboundBuffer is null we know the channel was closed and so // need to fail the future right away. If it is not null the handling of the rest // will be done in flush0() // See /netty/netty/issues/2362 safeSetFailure(promise, CLOSED_CHANNEL_EXCEPTION); // release message now to prevent resource-leak ReferenceCountUtil.release(msg); return; } outboundBuffer.addMessage(msg, promise); } 在代码的许多部分, 都会有这个 ClosedChannelException, 大概的意思是说在 channel close 以后, 如果还调用了 write 方法, 则会将 write 的 future 设置为 failure, 并将 cause 设置为 ClosedChannelException, 同样 SSLHandler 中也类似 ----------------- 回到 Connection reset by peer, 要模拟这个情况比较简单, 就是在 server 端设置一个在 channelActive 的时候就 close channel 的 handler. 而在 client 端则写一个 Connect 成功后立即发送请求数据的 listener. 如下 client public static void main(String[] args) throws IOException, InterruptedException { Bootstrap b = new Bootstrap(); b.group(new NioEventLoopGroup()) .channel(NioSocketChannel.class)