SNMP4J 服务端连接的超时时间

我们的网络管理中心作为管理中心，是服务端！各个被管设备通过交换机作为客户端与网管中心进行通信，使用的TCP/IP协议！

SNMP只是一种协议包，SNMP4J作为SNMP使用的Java工具包，提供了方便安全的工具包功能！

但是在使用中发现一个问题就是，服务端与客户端发送消息时，发送数次后就不再发送数据了！网络抓包也抓不到，跟踪断点到SNMP4J的代码中发现了这样一个问题！

[java]
/**
* Sends a SNMP message to the supplied address.
*
* @param address
*            an <code>TcpAddress</code>. A
*            <code>ClassCastException</code> is thrown if
*            <code>address</code> is not a <code>TcpAddress</code>
*            instance.
* @param message
*            byte[] the message to sent.
* @throws IOException
*/
public void sendMessage(Address address, byte[] message)
        throws java.io.IOException {
    if (server == null) {
        listen();
    }
    serverThread.sendMessage(address, message);
}

我们可以看到，他与UDP的不同是，使用了一个服务的线程！

[java]
public void sendMessage(Address address, byte[] message)
        throws java.io.IOException {
    Socket s = null;
    SocketEntry entry = (SocketEntry) sockets.get(address);
    if (logger.isDebugEnabled()) {
        logger.debug("Looking up connection for destination '"
                + address + "' returned: " + entry);
        logger.debug(sockets.toString());
    }
    if (entry != null) {
        s = entry.getSocket();
    }
    if ((s == null) || (s.isClosed()) || (!s.isConnected())) {
        if (logger.isDebugEnabled()) {
            logger.debug("Socket for address '" + address
                    + "' is closed, opening it...");
        }
        pending.remove(entry);
        SocketChannel sc = null;
        try {
            // Open the channel, set it to non-blocking, initiate
            // connect
            sc = SocketChannel.open();
            sc.configureBlocking(false);
            sc
                    .connect(new InetSocketAddress(
                            ((TcpAddress) address).getInetAddress(),
                            ((TcpAddress) address).getPort()));
            s = sc.socket();
            entry = new SocketEntry((TcpAddress) address, s);
            entry.addMessage(message);
            sockets.put(address, entry);

            synchronized (pending) {
                pending.add(entry);
            }

            selector.wakeup();
            logger.debug("Trying to connect to " + address);
        } catch (IOException iox) {
            logger.error(iox);
            throw iox;
        }
    } else {
        entry.addMessage(message);
        synchronized (pending) {
            pending.add(entry);
        }
        selector.wakeup();
    }
}

他从一个Map中去获得连接 SocketEntry ，然后得到连接对象Socket！

判断Socket是否有效，有效则直接发送，无效则创建连接后再发送！

然后我找到这样一段代码

[java]
private synchronized void timeoutSocket(SocketEntry entry) {
    if (connectionTimeout > 0) {
        socketCleaner.schedule(new SocketTimeout(entry), connectionTimeout);
    }
}

也就是说服务端会自己检查的连接并且去清除他！

我尝试设置 connectionTimeout 的值

[java]
private void init() throws UnknownHostException, IOException {
    threadPool = ThreadPool.create("Trap", 2);
    dispatcher = new MultiThreadedMessageDispatcher(threadPool,new MessageDispatcherImpl());
    // 本地IP与监听端口
    listenAddress = GenericAddress.parse(System.getProperty("snmp4j.listenAddress", "tcp:192.168.9.69/5055"));
    DefaultTcpTransportMapping transport;
    transport = new DefaultTcpTransportMapping((TcpAddress) listenAddress);
    transport.setConnectionTimeout(0);
    snmp = new Snmp(dispatcher, transport);
    snmp.getMessageDispatcher().addMessageProcessingModel(new MPv1());
    snmp.getMessageDispatcher().addMessageProcessingModel(new MPv2c());
    snmp.getMessageDispatcher().addMessag

补充：软件开发 , Java ,