我們的網(wǎng)絡(luò)管理中心作為管理中心，是服務(wù)端！各個(gè)被管設(shè)備通過(guò)交換機(jī)作為客戶端與網(wǎng)管中心進(jìn)行通信，使用的TCP/IP協(xié)議！
SNMP只是一種協(xié)議包，SNMP4J作為SNMP使用的Java工具包，提供了方便安全的工具包功能！
但是在使用中發(fā)現(xiàn)一個(gè)問(wèn)題就是，服務(wù)端與客戶端發(fā)送消息時(shí)，發(fā)送數(shù)次后就不再發(fā)送數(shù)據(jù)了！網(wǎng)絡(luò)抓包也抓不到，跟蹤斷點(diǎn)到SNMP4J的代碼中發(fā)現(xiàn)了這樣一個(gè)問(wèn)題！
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/** * 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);} |
我們可以看到，他與UDP的不同是，使用了一個(gè)服務(wù)的線程！
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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(); }} |
他從一個(gè)Map中去獲得連接 SocketEntry ，然后得到連接對(duì)象Socket！
判斷Socket是否有效，有效則直接發(fā)送，無(wú)效則創(chuàng)建連接后再發(fā)送！
然后我找到這樣一段代碼
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private synchronized void timeoutSocket(SocketEntry entry) { if (connectionTimeout > 0) { socketCleaner.schedule(new SocketTimeout(entry), connectionTimeout); } } |
也就是說(shuō)服務(wù)端會(huì)自己檢查的連接并且去清除他！
我嘗試設(shè)置 connectionTimeout 的值
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private void init() throws UnknownHostException, IOException { threadPool = ThreadPool.create("Trap", 2); dispatcher = new MultiThreadedMessageDispatcher(threadPool,new MessageDispatcherImpl()); // 本地IP與監(jiān)聽(tīng)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().addMessageProcessingModel(new MPv3()); USM usm = new USM(SecurityProtocols.getInstance(), new OctetString(MPv3.createLocalEngineID()), 0); SecurityModels.getInstance().addSecurityModel(usm); snmp.listen(); } |
增加一行代碼 設(shè)置DefaultTcpTransportMapping的超時(shí)時(shí)間是 0 ！
然后就沒(méi)有問(wèn)題了！
雖然臨時(shí)解決了問(wèn)題，但是由于對(duì)SNMP4J不夠深入了解，我怕問(wèn)題恐怕不是這樣的！
我在此也希望使用SNMP4J為工具，且作為服務(wù)端，在發(fā)送數(shù)據(jù)時(shí)有問(wèn)題的解決方法！
以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持服務(wù)器之家。
原文鏈接：https://www.iteye.com/blog/cuisuqiang-1685183
