JMX

JMX简介

JMX(Java Management Extensions)是一个为应用程序植入管理功能的框架。JMX是一套标准的代理和服务，实际上，用户可以在任何Java应用程序中使用这些代理和服务实现管理。这是官方文档上的定义，我看过很多次也无法很好的理解。我个人的理解是JMX让程序有被管理的功能，例如你开发一个WEB网站，它是在24小时不间断运行，那么你肯定会对网站进行监控，如每天的UV、PV是多少；又或者在业务高峰的期间，你想对接口进行限流，就必须去修改接口并发的配置值。

 JMX架构图

案例：

Mbean

package com.hpe.jmx;
//MBean接口
public interface HelloMBean {

    public String getName();

    public void setName(String name);

    public String getAge();

    public void setAge(String age);

    public String helloWorld();

    public void helloWorld(String str);

    public void getTelephone();
}

package com.hpe.jmx;

import java.security.PublicKey;
//Mbean的实现
public class Hello implements HelloMBean {

    private String name;

    private String age;
    public Hello(String name,String age){
        this.name = name;
        this.age = age;
    }

    public void getTelephone() {
        System.out.println("get Telephone");
    }

    public String helloWorld() {
        System.out.println("hello world");
        return "gaojy";
    }

    public void helloWorld(String str) {
        System.out.println("helloWorld:" + str);
    }

    public String getName() {
        System.out.println("get name 123");
        return name;
    }

    public void setName(String name) {
        System.out.println("set name 123");
        this.name = name;
    }

    public String getAge() {
        System.out.println("get age 123");
        return age;
    }

    public void setAge(String age) {
        System.out.println("set age 123");
        this.age = age;
    }
}

适配层：MBeanServer，主要是提供对资源的注册和管理。

接入层：提供远程访问的入口。

package com.hpe.jmx;

import java.lang.management.ManagementFactory;
import java.rmi.registry.LocateRegistry;

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

public class helloAgent {
    public static void main(String[] args) throws JMException, Exception {
        //适配层
        MBeanServer server = ManagementFactory.getPlatformMBeanServer();
        ObjectName helloName = new ObjectName("jmxBean:name=hello");
        // create mbean and register mbean
        //创建并注册Mbean
        server.registerMBean(new Hello("gaojy","24"), helloName);
        try {
            //这个步骤很重要，注册一个端口，绑定url后用于客户端通过rmi方式连接JMXConnectorServer
            LocateRegistry.createRegistry(9999);
            // URL路径的结尾可以随意指定，但如果需要用Jconsole来进行连接，则必须使用jmxrmi
            JMXServiceURL url = new JMXServiceURL
                      ("service:jmx:rmi:///jndi/rmi://localhost:9999/jmxrmi");
                JMXConnectorServer jcs = JMXConnectorServerFactory.newJMXConnectorServer(url, null, server);
                System.out.println("begin rmi start");
                jcs.start();
                System.out.println("rmi start");
        } catch (Exception e) {
            // TODO: handle exception
        }
        Thread.sleep(60 * 60 * 1000);
    }
}

客户端：

package com.hpe.jmx;

import java.io.IOException;
import java.net.MalformedURLException;

import javax.management.Attribute;
import javax.management.AttributeNotFoundException;
import javax.management.InstanceNotFoundException;
import javax.management.InvalidAttributeValueException;
import javax.management.MBeanException;
import javax.management.MBeanServerConnection;
import javax.management.MBeanServerInvocationHandler;
import javax.management.MalformedObjectNameException;
import javax.management.ObjectName;
import javax.management.ReflectionException;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;

public class Client {
    public static void main(String[] args) throws Exception {

        JMXServiceURL url = new JMXServiceURL(
                "service:jmx:rmi:///jndi/rmi://localhost:9999/jmxrmi");
        JMXConnector jmxc = JMXConnectorFactory.connect(url, null);
        MBeanServerConnection mbsc = jmxc.getMBeanServerConnection();
        // ObjectName的名称与前面注册时候的保持一致
        ObjectName mbeanName = new ObjectName("jmxBean:name=hello");

        System.out.println("Domains ......");
        String[] domains = mbsc.getDomains();

        for (int i = 0; i < domains.length; i++) {
            System.out.println("doumain[" + i + "]=" + domains[i]);
        }

        System.out.println("MBean count = " + mbsc.getMBeanCount());
        // 设置指定Mbean的特定属性值
        // 这里的setAttribute、getAttribute操作只能针对bean的属性
        // 例如对getName或者setName进行操作，只能使用Name，需要去除方法的前缀
        mbsc.setAttribute(mbeanName, new Attribute("Name", "杭州"));// 远程设置
        mbsc.setAttribute(mbeanName, new Attribute("Age", "1990"));
        String age = (String) mbsc.getAttribute(mbeanName, "Age"); // 远程获取
        String name = (String) mbsc.getAttribute(mbeanName, "Name");
        System.out.println("age=" + age + ";name=" + name);

        // 远程方法调用
        HelloMBean proxy = MBeanServerInvocationHandler.newProxyInstance(mbsc,
                mbeanName, HelloMBean.class, false);
        proxy.helloWorld();
        proxy.helloWorld("migu");
        proxy.getTelephone();
        // invoke调用bean的方法，只针对非设置属性的方法
        // 例如invoke不能对getName方法进行调用
        mbsc.invoke(mbeanName, "getTelephone", null, null);
        mbsc.invoke(mbeanName, "helloWorld",
                new String[] { "I'll connect to JMX Server via client2" },
                new String[] { "java.lang.String" });
        mbsc.invoke(mbeanName, "helloWorld", null, null);
    }
}

参考

http://www.cnblogs.com/dongguacai/p/5900507.html