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！
/**
* 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！
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
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
private void init() throws UnknownHostException, IOException {
threadPool = ThreadPool.create("Trap", 2);
dispatcher = new MultiThreadedMessageDispatcher(threadPool,new MessageDispatcherImpl());
// 本地IP與監(jiān)聽端口
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腳本之家。
