netty: WARNING:触发了exceptionCaught()事件，它到达了管道的尾部

Question

我为我的客户端编写了服务来处理多个客户端，它工作得很好，但是最近几天客户端的负载增加了，现在服务器代码产生了异常，我不能理解它是怎么回事。

我的代码是：

    public void run() throws Exception {

    //System.setProperty("org.jboss.netty.epollBugWorkaround", "true");
    EventLoopGroup bossPool = new NioEventLoopGroup(BOSS_THREADS);
    EventLoopGroup workerPool = new NioEventLoopGroup(MAX_WORKER_THREADS);

    try {

        ServerBootstrap boot = new ServerBootstrap();
        boot.group(bossPool, workerPool);
        boot.channel(NioServerSocketChannel.class);
        boot.childHandler(new Pipeline());
        boot.option(ChannelOption.TCP_NODELAY, true);
        boot.option(ChannelOption.SO_KEEPALIVE, true);
        boot.option(ChannelOption.SO_REUSEADDR, true);
        boot.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 6000);
        boot.option(ChannelOption.SO_TIMEOUT, 6);
        boot.option(ChannelOption.SO_BACKLOG, 2048);

        //System.out.println("Server started listening at port : " + port);
        boot.bind(port).sync().channel().closeFuture().sync();

    } catch (InterruptedException e) {
    } finally {
        workerPool.shutdownGracefully();
        bossPool.shutdownGracefully();
    }
}

管道代码为：

    public class Pipeline extends ChannelInitializer<Channel> {
    @Override
    protected void initChannel(Channel ch) throws Exception {
        // ch.pipeline().addLast("joiner", new JoinRequest());
        ch.pipeline().addLast("decoder", new ByteArrayDecoder());
        ch.pipeline().addLast("encoder", new StringEncoder());
        ch.pipeline().addLast("myHelper", new RequestHandler());
       }
    }

这是我每天得到的详细的错误日志：

1006465:54:21:10-16-03-2017Mar 16, 2017 10:21:54 AM         io.netty.channel.DefaultChannelPipeline$TailContext exceptionCaught
WARNING: An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
java.io.IOException: Too many open files
    at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method)
    at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:422)
    at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:250)
    at io.netty.channel.socket.nio.NioServerSocketChannel.doReadMessages(NioServerSocketChannel.java:135)
    at io.netty.channel.nio.AbstractNioMessageChannel$NioMessageUnsafe.read(AbstractNioMessageChannel.java:69)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:514)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:471)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:385)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:351)
    at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
    at io.netty.util.internal.chmv8.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1412)
    at io.netty.util.internal.chmv8.ForkJoinTask.doExec(ForkJoinTask.java:280)
    at io.netty.util.internal.chmv8.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:877)
    at io.netty.util.internal.chmv8.ForkJoinPool.scan(ForkJoinPool.java:1706)
    at io.netty.util.internal.chmv8.ForkJoinPool.runWorker(ForkJoinPool.java:1661)
    at io.netty.util.internal.chmv8.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:126)

com.idea.builders.RequestHandler oprationSelector
SEVERE: null
java.io.FileNotFoundException: config.dat (Too many open files)
    at java.io.FileInputStream.open0(Native Method)
    at java.io.FileInputStream.open(FileInputStream.java:195)
    at java.io.FileInputStream.<init>(FileInputStream.java:138)
    at java.io.FileInputStream.<init>(FileInputStream.java:93)
    at java.io.FileReader.<init>(FileReader.java:58)
    at com.idea.builders.RequestHandler.oprationSelector(RequestHandler.java:175)
    at com.idea.builders.RequestHandler.messageReceived(RequestHandler.java:97)
    at com.idea.builders.RequestHandler.messageReceived(RequestHandler.java:35)
    at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105)
    at io.netty.channel.ChannelHandlerInvokerUtil.invokeChannelReadNow(ChannelHandlerInvokerUtil.java:84)
    at io.netty.channel.DefaultChannelHandlerInvoker.invokeChannelRead(DefaultChannelHandlerInvoker.java:153)
    at io.netty.channel.PausableChannelEventExecutor.invokeChannelRead(PausableChannelEventExecutor.java:86)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:389)
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)
    at io.netty.channel.ChannelHandlerInvokerUtil.invokeChannelReadNow(ChannelHandlerInvokerUtil.java:84)
    at io.netty.channel.DefaultChannelHandlerInvoker.invokeChannelRead(DefaultChannelHandlerInvoker.java:153)
    at io.netty.channel.PausableChannelEventExecutor.invokeChannelRead(PausableChannelEventExecutor.java:86)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:389)
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:956)
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:127)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:514)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:471)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:385)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:351)
    at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
    at io.netty.util.internal.chmv8.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1412)
    at io.netty.util.internal.chmv8.ForkJoinTask.doExec(ForkJoinTask.java:280)
    at io.netty.util.internal.chmv8.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:877)
    at io.netty.util.internal.chmv8.ForkJoinPool.scan(ForkJoinPool.java:1706)
    at io.netty.util.internal.chmv8.ForkJoinPool.runWorker(ForkJoinPool.java:1661)
    at io.netty.util.internal.chmv8.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:126)

Mar 16, 2017 10:21:54 AM com.idea.builders.RequestHandler oprationSelector
SEVERE: null
java.io.FileNotFoundException: config.dat (Too many open files)
    at java.io.FileInputStream.open0(Native Method)
    at java.io.FileInputStream.open(FileInputStream.java:195)
    at java.io.FileInputStream.<init>(FileInputStream.java:138)
    at java.io.FileInputStream.<init>(FileInputStream.java:93)
    at java.io.FileReader.<init>(FileReader.java:58)
    at com.idea.builders.RequestHandler.oprationSelector(RequestHandler.java:175)
    at com.idea.builders.RequestHandler.messageReceived(RequestHandler.java:97)
    at com.idea.builders.RequestHandler.messageReceived(RequestHandler.java:35)

我应该怎么做才能每天重新启动我的服务器？

Answer 1

您应该在其中一个处理程序中重写exceptionCaught方法。

该消息表示netty caugth异常，但您没有在任何处理程序中处理它。异常只会到达最后一个管道处理程序并消失。您可能应该在请求处理程序中处理它。

是的，在你处理完文件后，关闭所有的流。此外，您还应该在异常或未注册事件时释放套接字和其他资源。