使用Java进行SNMP编程-SNMP4J-SNMPv1/v2-代码实例

使用SNMP4J可以很方便的实现一个SNMP NMS的功能。

对于SNMPv1/SNMPv2，简单的说，只需要以下几个步骤

1) 创建Snmp对象snmp

2) 创建CommunityTarget对象target，并指定community, version, address, timeout, retry等参数。

3) 创建PDU对象pdu，并指定操作类型(GET/GETNEXT/GETBULK/SET)， 添加VariableBinding(也就是待操作的OID),

如果是GETBULK操作，还可以指定MaxRepetitions和NonRepeaters。

注意一定要指定MaxRepetitions，默认值是0，那样不会返回任何结果。

4) 调用snmp.send(pdu, target)方法，发送请求请返回结果。

此外，SNMP4J提供了TableUtils类，可以很轻松的实现一个SNMP Walk的功能，比如一次返回一个表格下面的所有MIB值。

TableUtils类还支持指定ower bound index 和 upper bound index， 得到更小范围的结果以提高性能。这一点对于从一个很多行的表中取一部分行的数据来说很重要。

Snmp还支持异步的send方法。

下面的代码实例实现了GET, GETNEXT, GETBULK, Walk, SET操作，

以及一个利用异步send方法实现的agent discovery： 对一个广播地址发送请求，等待agent返回的应答。

如果需要对一个范围内的IP进行扫描，可以稍加改进，反复调用异步send多次发送给不同IP。

import java.io.IOException;
import java.util.List;
import java.util.Vector;

import org.snmp4j.CommunityTarget;
import org.snmp4j.PDU;
import org.snmp4j.Snmp;
import org.snmp4j.event.ResponseEvent;
import org.snmp4j.event.ResponseListener;
import org.snmp4j.mp.SnmpConstants;
import org.snmp4j.smi.OID;
import org.snmp4j.smi.OctetString;
import org.snmp4j.smi.UdpAddress;
import org.snmp4j.smi.VariableBinding;
import org.snmp4j.transport.DefaultUdpTransportMapping;
import org.snmp4j.util.DefaultPDUFactory;
import org.snmp4j.util.TableEvent;
import org.snmp4j.util.TableUtils;

public class SNMPv2Test {
public static void main(String[] args) throws IOException, InterruptedException {
Snmp snmp = new Snmp(new DefaultUdpTransportMapping());
snmp.listen();

CommunityTarget target = new CommunityTarget();
target.setCommunity(new OctetString("public"));
target.setVersion(SnmpConstants.version2c);
target.setAddress(new UdpAddress("192.168.0.100/161"));
target.setTimeout(3000);	//3s
target.setRetries(1);

sendRequest(snmp, createGetPdu(), target);
sendRequest(snmp, createGetNextPdu(), target);
sendRequest(snmp, createGetBulkPdu(), target);
snmpWalk(snmp, target);

target.setCommunity(new OctetString("private"));
sendRequest(snmp, createSetPdu(), target);

CommunityTarget broadcastTarget = new CommunityTarget();
broadcastTarget.setCommunity(new OctetString("public"));
broadcastTarget.setVersion(SnmpConstants.version2c);
broadcastTarget.setAddress(new UdpAddress("192.168.0.255/161"));
broadcastTarget.setTimeout(5000);	//5s
sendAsyncRequest(snmp, createGetNextPdu(), broadcastTarget);
Thread.sleep(6000);	//main thread wait 6s for the completion of asynchronous request
}

private static PDU createGetPdu() {
PDU pdu = new PDU();
pdu.setType(PDU.GET);
pdu.add(new VariableBinding(new OID("1.3.6.1.2.1.1.3.0")));	//sysUpTime
pdu.add(new VariableBinding(new OID("1.3.6.1.2.1.1.5.0")));	//sysName
pdu.add(new VariableBinding(new OID("1.3.6.1.2.1.1.5")));	//expect an no_such_instance error
return pdu;
}

private static PDU createGetNextPdu() {
PDU pdu = new PDU();
pdu.setType(PDU.GETNEXT);
pdu.add(new VariableBinding(new OID("1.3.6.1.2.1.1.3")));	//sysUpTime
pdu.add(new VariableBinding(new OID("1.3.6.1.2.1.1.5")));	//sysName

return pdu;
}

private static PDU createGetBulkPdu() {
PDU pdu = new PDU();
pdu.setType(PDU.GETBULK);
pdu.setMaxRepetitions(10);	//must set it, default is 0
pdu.setNonRepeaters(0);
pdu.add(new VariableBinding(new OID("1.3.6.1.2.1.1")));		//system
return pdu;
}

private static PDU createSetPdu() {
PDU pdu = new PDU();
pdu.setType(PDU.SET);
pdu.add(new VariableBinding(new OID("1.3.6.1.2.1.1.5.0"), new OctetString("sysname")));	//sysName
return pdu;
}

private static void sendRequest(Snmp snmp, PDU pdu, CommunityTarget target)
throws IOException {
ResponseEvent responseEvent = snmp.send(pdu, target);
PDU response = responseEvent.getResponse();

if (response == null) {
System.out.println("TimeOut...");
} else {
if (response.getErrorStatus() == PDU.noError) {
Vector<? extends VariableBinding> vbs = response.getVariableBindings();
for (VariableBinding vb : vbs) {
System.out.println(vb + " ," + vb.getVariable().getSyntaxString());
}
} else {
System.out.println("Error:" + response.getErrorStatusText());
}
}
}

private static void sendAsyncRequest(Snmp snmp, PDU pdu, CommunityTarget target)
throws IOException {
snmp.send(pdu, target, null, new ResponseListener(){

@Override
public void onResponse(ResponseEvent event) {
PDU response = event.getResponse();
System.out.println("Got response from " + event.getPeerAddress());
if (response == null) {
System.out.println("TimeOut...");
} else {
if (response.getErrorStatus() == PDU.noError) {
Vector<? extends VariableBinding> vbs = response.getVariableBindings();
for (VariableBinding vb : vbs) {
System.out.println(vb + " ," + vb.getVariable().getSyntaxString());
}
} else {
System.out.println("Error:" + response.getErrorStatusText());
}
}
}});
}

private static void snmpWalk(Snmp snmp, CommunityTarget target) {
TableUtils utils = new TableUtils(snmp, new DefaultPDUFactory(PDU.GETBULK));//GETNEXT or GETBULK
utils.setMaxNumRowsPerPDU(5);	//only for GETBULK, set max-repetitions, default is 10
OID[] columnOids = new OID[] {
new OID("1.3.6.1.2.1.1.9.1.2"),	//sysORID
new OID("1.3.6.1.2.1.1.9.1.3"),	//sysORDescr
new OID("1.3.6.1.2.1.1.9.1.5")	//wrong OID, expect an null in in VariableBinding array
};
// If not null, all returned rows have an index in a range (lowerBoundIndex, upperBoundIndex]
List<TableEvent> l = utils.getTable(target, columnOids, new OID("3"), new OID("10"));
for (TableEvent e : l) {
System.out.println(e);
}
}
}