There are lots of open source library for SNMP is available, even java have library for the same, But in this article I will explain a simple example of using SNMP4j in JAVA to create a simple client which will display the hardware information.
Note : To run this program, SNMP service must be installed. Check this article to know that how to install SNMP in Windows XP.
Download libraries from http://www.snmp4j.org/html/download.html
Create Simple NMS (Network management station / Client) in JAVA using SNMP4j:
package com.G2.SNMP.client;
import java.io.IOException;
import org.snmp4j.CommunityTarget;
import org.snmp4j.PDU;
import org.snmp4j.Snmp;
import org.snmp4j.Target;
import org.snmp4j.TransportMapping;
import org.snmp4j.event.ResponseEvent;
import org.snmp4j.mp.SnmpConstants;
import org.snmp4j.smi.Address;
import org.snmp4j.smi.GenericAddress;
import org.snmp4j.smi.OID;
import org.snmp4j.smi.OctetString;
import org.snmp4j.smi.VariableBinding;
import org.snmp4j.transport.DefaultUdpTransportMapping;
public class SNMPManager {
Snmp snmp = null;
String address = null;
/**
* Constructor
* @param add
*/
public SNMPManager(String add)
{
address = add;
}
public static void main(String[] args) throws IOException {
/**
* Port 161 is used for Read and Other operations
* Port 162 is used for the trap generation
*/
SNMPManager client = new SNMPManager("udp:127.0.0.1/161");
client.start();
/**
* OID - .1.3.6.1.2.1.1.1.0 => SysDec
* OID - .1.3.6.1.2.1.1.5.0 => SysName
* => MIB explorer will be usefull here, as discussed in previous article
*/
String sysDescr = client.getAsString(new OID(".1.3.6.1.2.1.1.1.0"));
System.out.println(sysDescr);
}
/**
* Start the Snmp session. If you forget the listen() method you will not
* get any answers because the communication is asynchronous
* and the listen() method listens for answers.
* @throws IOException
*/
private void start() throws IOException {
TransportMapping transport = new DefaultUdpTransportMapping();
snmp = new Snmp(transport);
// Do not forget this line!
transport.listen();
}
/**
* Method which takes a single OID and returns the response from the agent as a String.
* @param oid
* @return
* @throws IOException
*/
public String getAsString(OID oid) throws IOException {
ResponseEvent event = get(new OID[] { oid });
return event.getResponse().get(0).getVariable().toString();
}
/**
* This method is capable of handling multiple OIDs
* @param oids
* @return
* @throws IOException
*/
public ResponseEvent get(OID oids[]) throws IOException {
PDU pdu = new PDU();
for (OID oid : oids) {
pdu.add(new VariableBinding(oid));
}
pdu.setType(PDU.GET);
ResponseEvent event = snmp.send(pdu, getTarget(), null);
if(event != null) {
return event;
}
throw new RuntimeException("GET timed out");
}
/**
* This method returns a Target, which contains information about
* where the data should be fetched and how.
* @return
*/
private Target getTarget() {
Address targetAddress = GenericAddress.parse(address);
CommunityTarget target = new CommunityTarget();
target.setCommunity(new OctetString("public"));
target.setAddress(targetAddress);
target.setRetries(2);
target.setTimeout(1500);
target.setVersion(SnmpConstants.version2c);
return target;
}
}
Output:
Hardware: x86 Family 6 Model 23 Stepping 10 AT/AT COMPATIBLE – Software: Windows 2000 Version 5.1 (Build 2600 Multiprocessor Free)
Explanation of every method is documented in above program. In Next article, we will write a Java Program to create SNMP Agent.
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