JMX : Standard MBean
Standard MBean由一个接口和一个实现类组成。
命名规范 :
接口 : XXXMBean
实现类 : XXX
按照约定，MBean的name为XXX。自定。
接口中的每个方法定义了一个attribute或operation。
以get或set开头的方法 : 如果符合getter或setter的模式，就是定义了一个attribute，类型为getter的返回值类型或setter参数类型。
其他方法 : 定义了一个operation。
示例:
package test.xue.mbean;
public interface HelloMBean {
public void sayHello();
public int add(int x, int y);
public String getName();
public int getCacheSize();
public void setCacheSize(int size);
public void setText();
public void settitle(String title);
}
HelloMBean接口定义了3个attribute和3个operation :
attributes:
name : readonly
cacheSize : readable and writable
title : writable
operations:
sayHello
add
setText : 不符合setter模式。
实现类:
package test.xue.mbean;
public class Hello implements HelloMBean {
private final String name = "My HelloMBean";
private int cacheSize = 1024;
private String title;
@Override
public void sayHello() {
System.out.println("hello, my HelloMBean");
}
@Override
public int add(int x, int y) {
return x+y;
}
@Override
public String getName() {
return name;
}
@Override
public int getCacheSize() {
return cacheSize;
}
@Override
public void setCacheSize(int size) {
this.cacheSize = size;
System.out.println("cacheSize changed : " + size);
}
@Override
public void setText() {
System.out.println("setText called");
}
@Override
public void settitle(String title) {
this.title = title;
System.out.println("title changed : " + title);
}
}
以上，HelloMBean和Hello就定义了一个MBean，通过这个MBean的operation和attribute，就可以管理特定的资源。
现在，就可以创建一个JMX agent来通过MBean管理资源了。
package test.xue.mbean.management;
import java.lang.management.ManagementFactory;
import javax.management.InstanceAlreadyExistsException;
import javax.management.MBeanRegistrationException;
import javax.management.MBeanServer;
import javax.management.MalformedObjectNameException;
import javax.management.NotCompliantMBeanException;
import javax.management.ObjectName;
import test.xue.mbean.Hello;
public class HelloAgent {
public static void main(String[] args) throws MalformedObjectNameException,
NullPointerException, InstanceAlreadyExistsException,
MBeanRegistrationException, NotCompliantMBeanException,
InterruptedException {
MBeanServer server = ManagementFactory.getPlatformMBeanServer();
ObjectName name = new ObjectName("test.xue.mbean:type=Hello"); // any name
// ObjectName name = new ObjectName("test.xue.mbean22:type=Hello2"); // also works
Hello mbean = new Hello();
server.registerMBean(mbean, name);
System.out.println("waiting here for remote management...");
Thread.sleep(Long.MAX_VALUE);
}
}
如上，每个MBean都需要一个ObjectName，ObjectName的命名规范:
domain:(key=value)+
例子中的domain=test.xue.mbean，type=Hello，可任意指定。
可通过JConsole来测试此JMX agent
运行 : jconsole
连接以后，
可以尝试修改attributes，调用operations，同时注意控制台输出。
如果出现javax.management.NotCompliantMBeanException :
Exception in thread "main" javax.management.NotCompliantMBeanException: MBean class test.xue.mbean.Hello2 does not implement DynamicMBean, neither follows the Standard MBean conventions (javax.management.NotCompliantMBeanException: Class test.xue.mbean.Hello2 is not a JMX compliant Standard MBean) nor the MXBean conventions (javax.management.NotCompliantMBeanException: test.xue.mbean.Hello2: Class test.xue.mbean.Hello2 is not a JMX compliant MXBean) at com.sun.jmx.mbeanserver.Introspector.checkCompliance(Unknown Source) at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(Unknown Source) at com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(Unknown Source) at test.xue.mbean.management.HelloAgent.main(HelloAgent.java:24)
可能的原因是:
接口和实现类的名字不符合命名规范: XXXMBean, XXX。