java.io.IOException：一个现有的连接被远程主机强行关闭

Question

我有一台运行 Apache FTPServer 的服务器。 FTP 服务器运行良好，直到最近一些来自客户端的上传开始失败，并附带此错误。我增加了 MaxIdleTimeout 但仍然遇到此错误。有人对实际产生此错误的原因有任何想法吗？

16 Mar 22:19:30,792 WARN [pool-3-thread-10] [LoggingFilter->log()]:122 - EXCEPTION :
java.io.IOException: An existing connection was forcibly closed by the remote host
    at sun.nio.ch.SocketDispatcher.read0(Native Method)
    at sun.nio.ch.SocketDispatcher.read(Unknown Source)
    at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source)
    at sun.nio.ch.IOUtil.read(Unknown Source)
    at sun.nio.ch.SocketChannelImpl.read(Unknown Source)
    at org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:202)
    at org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:42)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.read(AbstractPollingIoProcessor.java:620)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:598)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:587)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.access$400(AbstractPollingIoProcessor.java:61)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(AbstractPollingIoProcessor.java:969)
    at org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:64)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
16 Mar 22:19:30,792 WARN [pool-3-thread-10] [LoggingFilter->log()]:122 - EXCEPTION :
java.io.IOException: An existing connection was forcibly closed by the remote host
    at sun.nio.ch.SocketDispatcher.read0(Native Method)
    at sun.nio.ch.SocketDispatcher.read(Unknown Source)
    at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source)
    at sun.nio.ch.IOUtil.read(Unknown Source)
    at sun.nio.ch.SocketChannelImpl.read(Unknown Source)
    at org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:202)
    at org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:42)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.read(AbstractPollingIoProcessor.java:620)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:598)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:587)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.access$400(AbstractPollingIoProcessor.java:61)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(AbstractPollingIoProcessor.java:969)
    at org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:64)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
16 Mar 22:19:30,792 ERROR[pool-3-thread-10] [DefaultFtpHandler->exceptionCaught()]:156 - Exception caught, closing session
java.io.IOException: An existing connection was forcibly closed by the remote host
    at sun.nio.ch.SocketDispatcher.read0(Native Method)
    at sun.nio.ch.SocketDispatcher.read(Unknown Source)
    at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source)
    at sun.nio.ch.IOUtil.read(Unknown Source)
    at sun.nio.ch.SocketChannelImpl.read(Unknown Source)
    at org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:202)
    at org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:42)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.read(AbstractPollingIoProcessor.java:620)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:598)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:587)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.access$400(AbstractPollingIoProcessor.java:61)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(AbstractPollingIoProcessor.java:969)
    at org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:64)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
16 Mar 22:19:30,792 ERROR[pool-3-thread-10] [DefaultFtpHandler->exceptionCaught()]:156 - Exception caught, closing session
java.io.IOException: An existing connection was forcibly closed by the remote host
    at sun.nio.ch.SocketDispatcher.read0(Native Method)
    at sun.nio.ch.SocketDispatcher.read(Unknown Source)
    at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source)
    at sun.nio.ch.IOUtil.read(Unknown Source)
    at sun.nio.ch.SocketChannelImpl.read(Unknown Source)
    at org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:202)
    at org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:42)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.read(AbstractPollingIoProcessor.java:620)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:598)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:587)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor.access$400(AbstractPollingIoProcessor.java:61)
    at org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(AbstractPollingIoProcessor.java:969)
    at org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:64)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

Answer 1

看起来像错误所说的那样，服务器关闭了您的连接。通常这是由于您不活动而导致的。如果您不继续与服务器通信，它将关闭您的连接。如果连接空闲，您需要向它发送 NOOP 命令流，让它知道您仍然在那里。