Connection reset

[JohnSimith]

2025-12-24 11:22:26.764 [ERROR] 1597881 --- [tLoopGroup-3-96] c.c.s.l.DefaultExceptionListener         : Connection reset

java.net.SocketException: Connection reset
	at java.base/sun.nio.ch.SocketChannelImpl.throwConnectionReset(SocketChannelImpl.java:394) ~[?:?]
	at java.base/sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:426) ~[?:?]
	at io.netty.buffer.PooledByteBuf.setBytes(PooledByteBuf.java:255) ~[netty-buffer-4.1.109.Final.jar!/:4.1.109.Final]
	at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:1132) ~[netty-buffer-4.1.109.Final.jar!/:4.1.109.Final]
	at io.netty.channel.socket.nio.NioSocketChannel.doReadBytes(NioSocketChannel.java:357) ~[netty-transport-4.1.109.Final.jar!/:4.1.109.Final]
	at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:151) [netty-transport-4.1.109.Final.jar!/:4.1.109.Final]
	at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:788) [netty-transport-4.1.109.Final.jar!/:4.1.109.Final]
	at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:724) [netty-transport-4.1.109.Final.jar!/:4.1.109.Final]
	at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:650) [netty-transport-4.1.109.Final.jar!/:4.1.109.Final]
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:562) [netty-transport-4.1.109.Final.jar!/:4.1.109.Final]
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) [netty-common-4.1.109.Final.jar!/:4.1.109.Final]
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) [netty-common-4.1.109.Final.jar!/:4.1.109.Final]
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [netty-common-4.1.109.Final.jar!/:4.1.109.Final]
	at java.base/java.lang.Thread.run(Thread.java:842) [?:?]

please help me. how can i fix this bug?

[sanjomo]

@JohnSimith usually this happens when connection abruptly ends, in what scenario you are getting this, frequency of such exception etc add more details pls

[JohnSimith]

socket.disconnect();
socket.close();
socket = IO.socket(url , options)

when the network busy，I will frequently disconnect pre connection and connect another.

[sanjomo]

more details please, server config, how many active connections, data rate, ping delay, cpu ram usage, GC , java version details to debug further

[JohnSimith]

1. yml config

# netty-socketio server 服务端配置
socketio:
  host: localhost
  port: 8888
  # 设置最大每帧处理数据的长度，防止他人利用大数据来攻击服务器
  maxFramePayloadLength: 1048576
  # 设置http交互最大内容长度
  maxHttpContentLength: 1048576
  # socket连接数大小（如只监听一个端口boss线程组为1即可）
  bossCount: 1
  allowCustomRequests: true
  # 协议升级超时时间（毫秒），默认10秒。HTTP握手升级为ws协议超时时间
  upgradeTimeout: 10000
  # Ping消息超时时间（毫秒），默认60秒，这个时间间隔内没有接收到心跳消息就会发送超时事件
  pingTimeout: 10000
  # Ping消息间隔（毫秒），默认25秒。客户端向服务器发送一条心跳消息间隔
  pingInterval: 5000

2. bean inti

 @Bean
    public SocketIOServer socketIOServer() {
        SocketConfig socketConfig = new SocketConfig();
        socketConfig.setTcpKeepAlive(true);
        socketConfig.setTcpNoDelay(true);
        socketConfig.setSoLinger(0);
        socketConfig.setTcpSendBufferSize(1024 * 1024);
        socketConfig.setTcpReceiveBufferSize(1024 * 1024);
        socketConfig.setAcceptBackLog(1024);

        com.corundumstudio.socketio.Configuration config = new com.corundumstudio.socketio.Configuration();
        config.setSocketConfig(socketConfig);
        //配置这个名字只能本地连
//        config.setHostname(host);
        config.setPort(port);
        config.setMaxFramePayloadLength(maxFramePayloadLength);
        config.setMaxHttpContentLength(maxHttpContentLength);
        config.setBossThreads(bossCount);
        config.setAllowCustomRequests(allowCustomRequests);
        config.setUpgradeTimeout(upgradeTimeout);
        config.setPingTimeout(pingTimeout);
        config.setPingInterval(pingInterval);
        config.setExceptionListener(new ConnectionResetExceptionListener());
        config.setTransports(Transport.WEBSOCKET); // 仅WebSocket
        config.setWorkerThreads(Runtime.getRuntime().availableProcessors() * 8); // Worker线程数
        SocketIOServer socketIOServer = new SocketIOServer(config);
        socketIOServer.addNamespace("/");
        return socketIOServer;
    }

3. jdk version 17
4. connection reset handle

@Slf4j
public class ConnectionResetExceptionListener extends DefaultExceptionListener {

    @Override
    public boolean exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws InterruptedException {
        // 精准匹配Connection reset异常
        if (cause instanceof SocketException && "Connection reset".equals(cause.getMessage())) {
            // 1. 记录轻量日志（避免刷屏）
            log.warn("Connection reset, close socket connection: {}", ctx.channel().remoteAddress());
            ctx.disconnect();
            // 2. 优雅关闭连接（释放Channel资源）
            ctx.close();
            ctx.close().sync();
            return true;
        }
        // 其他异常按原有逻辑处理
//        return super.exceptionCaught(ctx, cause);
        return true;
    }
}