一、简介

      上一节介绍的是通过Web方式访问和操控MBean，本节所要介绍的是通过RMI方式，实现客户端与服务器端的通信，即客户端获取MBeanServerConnection，然后对服务器端被注册的MBean进行操作。

二、代码实例

2.1 mserver代码

package com.muyu.jmx;    import java.rmi.registry.LocateRegistry;  import java.rmi.registry.Registry;  import java.util.Collections;  import java.util.HashMap;  import java.util.HashSet;  import java.util.Map;  import java.util.Set;    import javax.management.MBeanServer;  import javax.management.MBeanServerFactory;  import javax.management.ObjectName;  import javax.management.remote.JMXAuthenticator;  import javax.management.remote.JMXConnectorServer;  import javax.management.remote.JMXConnectorServerFactory;  import javax.management.remote.JMXPrincipal;  import javax.management.remote.JMXServiceURL;  import javax.security.auth.Subject;    public class MServer {            public static void main(String[] args) {                    MBeanServer server = MBeanServerFactory.createMBeanServer();          ObjectName configName;          try {              configName = new ObjectName("LuisFigo:name=config");              Config config = new Config();              server.registerMBean(config, configName);              //注册RMI端口号              Registry registry = LocateRegistry.createRegistry(9999);              JMXServiceURL url = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://localhost:9999/mserver");                      //权限验证              Map env = new HashMap();              env.put(JMXConnectorServer.AUTHENTICATOR,                       new JMXAuthenticator() {                   public Subject authenticate(Object credentials) {                       String[] sCredentials = (String[]) credentials;                       String userName = sCredentials[0];                       String password = sCredentials[1];                       if ("admin".equals(userName) && "admin".equals(password)) {                           Set principals = new HashSet();                           principals.add(new JMXPrincipal(userName));                           return new Subject(true, principals, Collections.EMPTY_SET, Collections.EMPTY_SET);                          }                       else                           throw new SecurityException("Authentication failed! ");                       }                   }              );              JMXConnectorServer cs = JMXConnectorServerFactory.newJMXConnectorServer(url, env, server);                 cs.start();              System.out.println("rmi　start.....");                        } catch (Exception e) {              e.printStackTrace();          }                  }       }

2.2 mclient代码

package com.muyu.jmx;            import java.util.HashMap;      import java.util.Iterator;      import java.util.Map;      import java.util.Set;            import javax.management.Attribute;      import javax.management.MBeanServerConnection;      import javax.management.MBeanServerInvocationHandler;      import javax.management.ObjectName;      import javax.management.remote.JMXConnector;      import javax.management.remote.JMXConnectorFactory;      import javax.management.remote.JMXServiceURL;            public class MClient {                public static void main(String[] args) {              try {                  JMXServiceURL url = new JMXServiceURL(                          "service:jmx:rmi:///jndi/rmi://localhost:9999/mserver");                  Map env = new HashMap();                  env.put(JMXConnector.CREDENTIALS, new String[]{"admin", "admin"});                                    JMXConnector jmxc = JMXConnectorFactory.connect(url, env);                  MBeanServerConnection mbsc = jmxc.getMBeanServerConnection();                        Set names = mbsc.queryNames(null, null);                  for (Iterator i = names.iterator(); i.hasNext();) {                      System.out.println("\tObjectName = " + (ObjectName) i.next());                  }                        ObjectName stdMBeanName = new ObjectName("LuisFigo:name=config");                        mbsc.invoke(stdMBeanName, "printConfigLocation", new String[]{"helloworld"}, new String[]{"java.lang.String"});                  mbsc.setAttribute(stdMBeanName, new Attribute("ConfigLocation", "LuisFigo, this is a new configLocation"));                        ConfigMBean proxy = (ConfigMBean) MBeanServerInvocationHandler                          .newProxyInstance(mbsc, stdMBeanName, ConfigMBean.class, false);                  System.out.println(proxy.getConfigLocation());                  proxy.setConfigLocation("Beckham");                  System.out.println(proxy.getConfigLocation());                  proxy.printConfigLocation();                  jmxc.close();              } catch (Exception e) {                  e.printStackTrace();              }          }            }

说明

       运行MServer，其中LocateRegistry.createRegistry(9999)这段代码是为了注册RMI端口，下面JMXServiceURL会用 到9999这个端口。Env用于控制新连接器服务器的行为的一组属性，上面的部分代码是为了实现权限验证。如果客户端不输入正确的用户名和密码，则获取MServer服务端的连接。执行MClient，会发现一些有意思的现象，执行mbsc.invoke(stdMBeanName, "printConfigLocation", new String[]{"helloworld"}, new String[]{"java.lang.String"});这段代码时，其实是MServer端的MBean在执行printConfigLocation方法。假如MServer部署在一个JVM上，而MClient部署在另一个不同的JVM上，会得到同样的效果。不难看出利用远程调用方法也可以轻松实现分布式处理。

三、 总结

      使用JMX框架，可以用SUN自带的web方式管理MBean，也可以通过RMI接口自己实现对服务端MBean进行操作。下一节还会详细介绍Spring怎样集成MX4J实现JMX编程，MX4J自己实现了一套比较实用的界面来管理MBean。