当客户端连接打开时关闭 Netty 服务器

Question

我正在尝试关闭已打开连接的 Netty 服务器，但它只是挂起。这就是我所做的。

• 在一台机器上启动服务器，在另一台机器上启动客户端。
• 从客户端向我收到响应的服务器发送消息。
• 使用 Ctrl-C 关闭服务器

我已经在关闭 ChannelGroup 的服务器上注册了一个关闭钩子，并在 ServerBootstrap 上调用 releaseExternalResources（或者实际上我正在使用 protobuf-pro-duplex 库的 DuplexTcpServerBootstrap 来做到这一点）。无论如何，关机钩子在关机时被正确调用，但它永远不会返回。当我对正在发生的事情进行线程转储时，我可以看到两个有趣的堆栈：

   java.lang.Thread.State: TIMED_WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000006b0890950> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:226)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2082)
    at java.util.concurrent.ThreadPoolExecutor.awaitTermination(ThreadPoolExecutor.java:1433)
    at org.jboss.netty.util.internal.ExecutorUtil.terminate(ExecutorUtil.java:103)
    at org.jboss.netty.channel.socket.nio.AbstractNioWorkerPool.releaseExternalResources(AbstractNioWorkerPool.java:80)
    at org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory.releaseExternalResources(NioServerSocketChannelFactory.java:162)
    at org.jboss.netty.bootstrap.Bootstrap.releaseExternalResources(Bootstrap.java:319)
    at com.googlecode.protobuf.pro.duplex.server.DuplexTcpServerBootstrap.releaseExternalResources(DuplexTcpServerBootstrap.java:132)
    at com.xxx.yyy.node.NodeServer$2.run(NodeServer.java:104)
    at java.lang.Thread.run(Thread.java:722)

所以这是永远不会返回的关闭钩子线程。下面是另一个似乎正在等待通道的线程：

   java.lang.Thread.State: RUNNABLE
    at sun.nio.ch.EPollArrayWrapper.interrupt(Native Method)
    at sun.nio.ch.EPollArrayWrapper.interrupt(EPollArrayWrapper.java:274)
    at sun.nio.ch.EPollSelectorImpl.wakeup(EPollSelectorImpl.java:193)
    - locked <0x00000006b0896660> (a java.lang.Object)
    at java.nio.channels.spi.AbstractSelector$1.interrupt(AbstractSelector.java:210)
    at java.nio.channels.spi.AbstractSelector.begin(AbstractSelector.java:216)
    at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:80)
    at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:87)
    - locked <0x00000006b08964a8> (a sun.nio.ch.Util$2)
    - locked <0x00000006b0896498> (a java.util.Collections$UnmodifiableSet)
    - locked <0x00000006b0890d20> (a sun.nio.ch.EPollSelectorImpl)
    at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:98)
    at org.jboss.netty.channel.socket.nio.SelectorUtil.select(SelectorUtil.java:52)
    at org.jboss.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:208)
    at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:38)
    at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:102)
    at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)

我在 Linux 上使用 Netty 3.4.6.Final 和 Java 7.04。谢谢！

兄弟，弗兰克。

Answer 1

Netty服务器关闭

1. 关闭服务器通道
2. 关闭boss和worker执行者
3. 释放服务器引导资源

示例代码

ChannelFuture cf = serverChannel.close();
cf.awaitUninterruptibly();
bossExecutor.shutdown();
workerExecutor.shutdown();
thriftServer.releaseExternalResources();