[Java] JMX Connector의 Server, Client 활용

1) Server 

 

package org.jmxserver.main;
import java.rmi.registry.LocateRegistry;

import javax.management.MBeanServer;
import javax.management.MBeanServerFactory;
import javax.management.ObjectName;
import javax.management.remote.JMXConnectorServer;
import javax.management.remote.JMXConnectorServerFactory;
import javax.management.remote.JMXServiceURL;

import org.jmxserver.inter.CPUModel;

public class Server {
	private MBeanServer mbs = null;
	public Server() {
		mbs = MBeanServerFactory.createMBeanServer("");
		
		CPUModel model = new CPUModel();
		ObjectName name = null;
		JMXServiceURL serviceURL = null;
		
		try {
			System.setProperty("java.rmi.server.hostname","192.168.0.24");
			LocateRegistry.createRegistry(7777); //port
			serviceURL = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://192.168.0.24:7777/server");
			name = new ObjectName("CPUModel:name=CPUModel");
			JMXConnectorServer connector = JMXConnectorServerFactory.newJMXConnectorServer(serviceURL, null, mbs);
			mbs.registerMBean(model, name);
			connector.start();
		}
		catch(Exception e) {
			e.printStackTrace();
		}
	}
	public static void main(String argv[]) {
		new Server();
		System.out.println("Server Starting...");
		
	}
}

 

package org.jmxserver.inter;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.management.ManagementFactory;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class CPUModel implements CPUModelMBean {
    private final long threadId;
    private long lastCpuTime = 0;
    private long lastPoll = 0;

    public double getCput() {
        double cpu = -1;
        try {
            // start up the command in child process
            String cmd = "top -n 2 -b -d 0.2";
            Process child = Runtime.getRuntime().exec(cmd);

            // hook up child process output to parent
            InputStream lsOut = child.getInputStream();
            InputStreamReader r = new InputStreamReader(lsOut);
            BufferedReader in = new BufferedReader(r);

            // read the child process' output
            String line;
            int emptyLines = 0;
            while (emptyLines < 3) {
                line = in.readLine();
                if (line.length() < 1)
                    emptyLines++;
            }
            in.readLine();
            in.readLine();
            line = in.readLine();
            System.out.println("Parsing line " + line);
            String delims = "%";
            String[] parts = line.split(delims);
            System.out.println("Parsing fragment " + parts[0]);
            delims = " ";

            parts = parts[0].split(delims);
            cpu = Double.parseDouble(parts[parts.length - 1]);
        } catch (Exception e) { // exception thrown
            System.out.println("Command failed!");
        }
        return cpu;
    }

    @Override
    public String getString() {
        // TODO Auto-generated method stub
        return "hi";
    }

    @Override
    public Object getObject() {
        // TODO Auto-generated method stub
        return new CPUModel();
    }

    @Override
    public List<String> getList() {
        // TODO Auto-generated method stub
        return new ArrayList<String>();
    }

    @Override
    public String[] getArray() {
        // TODO Auto-generated method stub
        return new String[10];
    }

    @Override
    public Map<String, Object> getMap() {
        // TODO Auto-generated method stub
        return new HashMap<String, Object>();
    }

    /**
     * Creates a CpuStats object for a single thread.
     *
     * @param threadId The id of the thread to monitor
     *
     */
    public CPUModel(long threadId) {
        this.threadId = threadId;
        lastCpuTime = getTotalTime();
        lastPoll = System.nanoTime();
    }

    /**
     * Creates a CpuStatus object for all threads. The supplied statistics affect
     * all threads in the current VM.
     */
    public CPUModel() {
        threadId = -1;
        lastCpuTime = getTotalTime();
        lastPoll = System.nanoTime();
    }

    public long getRelativeTime() {
        long currentCpuTime = getTotalTime();
        long ret = currentCpuTime - lastCpuTime;
        lastCpuTime = currentCpuTime;

        return ret;
    }

    public double getUsage() {
        long timeBefore = this.lastPoll;

        lastPoll = System.nanoTime();
        long relTime = getRelativeTime();

        return Math.max((double) relTime / (double) (lastPoll - timeBefore), 0.0);
    }

    public long getTotalTime() {
        if (threadId == -1) {
            long cpuTime = 0;
            for (long id : ManagementFactory.getThreadMXBean().getAllThreadIds()) {
                cpuTime += ManagementFactory.getThreadMXBean().getThreadCpuTime(id);
            }

            return cpuTime;
        } else {
            return ManagementFactory.getThreadMXBean().getThreadCpuTime(threadId);
        }
    }
}

 

package org.jmxserver.inter;

import java.util.List;
import java.util.Map;

public interface CPUModelMBean {
	public long getRelativeTime();
	public double getUsage();
	public long getTotalTime();
	public double getCput();
	public String getString();
	public Object getObject();
	public List<String> getList();
	public String[] getArray();
	public Map<String, Object> getMap();
}

 

 

2) Client

 

package org.mbeans.hello;

import java.util.Arrays;

import javax.management.JMX;
import javax.management.MBeanServerConnection;
import javax.management.ObjectName;
import javax.management.RuntimeErrorException;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;

import org.jmxserver.inter.CPUModelMBean;

public class CPUClient {
	public static void main(String[] args) {
		foo();
	}

	public static void foo() {

		try {
			System.out.println("server init...");
			JMXServiceURL url = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://192.168.0.24:7777/server");
			System.out.println("connector init...");
			JMXConnector jmxc = JMXConnectorFactory.connect(url, null);

			System.out.println("connection init...");
			// Get an MBeanServerConnection
			MBeanServerConnection mbsc = jmxc.getMBeanServerConnection();

			// Get domains from MBeanServer
			String domains[] = mbsc.getDomains();
			Arrays.sort(domains);
			for (String domain : domains) {
				System.out.println(domain);
			}

			// JMXServer에서 등록한 ObjectName 생성
			ObjectName mbeanName = new ObjectName("CPUModel:name=CPUModel");

			// Create a dedicated proxy for the MBean instead of
			// going directly through the MBean server connection
			CPUModelMBean model = JMX.newMBeanProxy(mbsc, mbeanName, CPUModelMBean.class, true);

			// start job
			System.out.println("getRelativeTime = " + model.getRelativeTime());
			System.out.println("getUsage = " + model.getUsage());
			System.out.println("getTotalTime = " + model.getTotalTime());
			System.out.println("getCput = " + model.getCput());
			System.out.println("getString = " + model.getString());
			System.out.println("getObject = " + model.getObject()); // 오브젝트 클래스에 대한 마샬링이 필요
			System.out.println("getList = " + model.getList());
			System.out.println("getArray = " + model.getArray());
			System.out.println("getMap = " + model.getMap());

		} catch (RuntimeErrorException e) {
			System.out.println("Error --->" + e);
			e.printStackTrace();
		} catch (Exception e) {
			System.out.println(e);
			e.printStackTrace();
		}
	}
}

 

 

• Server 측의 MBeans에 해당하는 CPUModel과 CPUModelMBeans 클래스와 인터페이스를 Client 측에서도 똑같이 구현 해주어야 한다.
• 포트와 아이피 주소는 임의로 지정해주어야 한다.
• 필자는 Server를 Oracle 가상머신에 우분투를 설치한 후 기동했고, Client는 Window에서 기동했다.

 

3) 실행 결과

 

Client 측

server init...
connector init...
connection init...
JMImplementation
org.jmxserver.inter.CPUModel
getRelativeTime = 180594092
getUsage = 7.489918770553646E-4
getTotalTime = 287235313
getCput = -1.0
getString = hi
getObject = org.jmxserver.inter.CPUModel@446cdf90
getList = []
getArray = [Ljava.lang.String;@22d8cfe0
getMap = {}

 

Server 측

 

 

 

 

4) 코드 해석

 

• 위 코드는 Server 측의 CPU 상태를 확인하는 기능과 Server, Client에 String, Map, List, Object 등의 변수 타입들이 잘 받아지는지 확인하기 위한 코드이다.

 

 

5)  error unmarshalling return; nested exception is: no security manager: RMI class loader disabled 에러 발생 시의 조치

 

• error unmarshalling return; nested exception is: no security manager: RMI class loader disabled 에러 발생 했을 때의 조치다.
• 서버에서 반환하는 Object 클래스를 받을 형태가 클라이언트에서 정의되지 않아서 발생하는 문제 => 서버에서 돌려주는 Object의 패키지 이름과 클래스 명을 갖게 해야함. Ex) 서버에서 정의된 이름이 org.jmxserver.inter.CPUModel 이면 클라이언트에서도 똑같이 정의해주어야 함.
• 서버 측에서의 클래스가 아래와 같다면,

 

 

 

•  클라이언트 측에서도 클래스와 패키지를 아래와 같이 지정해주어야 한다.