三、JMX服務器端鏈接

1、簡介

      上一節介紹的是經過Web方式訪問和操控MBean，本節所要介紹的是經過RMI方式，實現客戶端與服務器端的通訊，即客戶端獲取MBeanServerConnection，而後對服務器端被註冊的MBean進行操做。

2、代碼實例

2.1 mserver代碼

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);  
  
          //註冊RMI端口號  
            Registry registry = LocateRegistry.createRegistry(9999);  
            JMXServiceURL url = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://localhost:9999/mserver");          
            //權限驗證  
            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代碼

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();  
            }  
        }  
      
    }

 

 

說明

       運行MServer，其中LocateRegistry.createRegistry(9999)這段代碼是爲了註冊RMI端口，下面JMXServiceURL會用 到9999這個端口。Env用於控制新鏈接器服務器的行爲的一組屬性，上面的部分代碼是爲了實現權限驗證。若是客戶端不輸入正確的用戶名和密碼，則獲取MServer服務端的鏈接。執行MClient，會發現一些有意思的現象，執行mbsc.invoke(stdMBeanName, "printConfigLocation", new String[]{"helloworld"}, new String[]{"java.lang.String"});這段代碼時，實際上是MServer端的MBean在執行printConfigLocation方法。假如MServer部署在一個JVM上，而MClient部署在另外一個不一樣的JVM上，會獲得一樣的效果。不難看出利用遠程調用方法也能夠輕鬆實現分佈式處理。

3、 總結

      使用JMX框架，能夠用SUN自帶的web方式管理MBean，也能夠經過RMI接口本身實現對服務端MBean進行操做。下一節還會詳細介紹Spring怎樣集成MX4J實現JMX編程，MX4J本身實現了一套比較實用的界面來管理MBean。