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前面的Model MBean的创建方式看上去特别复杂,一个简单功能的类ModelMBeanUtils 写了很多代码,那有木有简单点的方式呢,答案是肯定的,这里就引出了Apache Commons Modeler(使用这个需要在classpath中导入commons-modeler-2.0.1.jar以及modeler的依赖项目commons-logging-1.1.3.jar,下载地址:),使用Apache的Moleler库创建Model MBean最大帮助是,我们不需要再写复杂的代码来创建ModelMBeanInfo对象了。只需要一个MBean描述符(实际上就是一个xml配置文件,Apache Commons Modeler将ModelMBeanUtils 复杂的创建过程转移到xml中来配置,然后自身模块创建对象代替ModelMBeanUtils 的功能,简化用户的操作)来对Model MBean进行描述,就可以轻松的创建Model MBean.
下面来讲前面的Hello.java和HelloAgent.java的例子采用Apache Commons Modele进行改造。
首先还是Hello.java,和Model MBean中的一样,没有implements任何接口。
package com.test.jmx.modeler;public class Hello{ private String name; public String getName() { return name; } public void setName(String name) { this.name= name; } public void printHello() { System.out.println("Hello World, "+name); } public void printHello(String whoName) { System.out.println("Hello, "+whoName); }}
接下去就是最关键的描述文件(mbeans-descriptors.xml)了:
描述文件的名字可以随意,最主要的是要和下面的HelloAgent.java对应起来。
通过这个xml文件的定义就描述了Model MBean所需要的metadata信息和一个基本的ModelMBean实现。 关于这个xml文件有几个需要说明的地方:<mbean>的属性classname,name,type:
其余的标签就比较好理解了。综述:上面所示代码声明了一个Model MBean, 唯一标示是“Hello”,该MBean负责管理的对象是com.test.jmx.modeler.Hello的实例。域是MyMBean。这个MBean暴露了一个属性name和两个方法printHello()和printHello(String whoName).
下面是新的HelloAgent.java的代码:
package com.test.jmx.modeler;import com.sun.jdmk.comm.HtmlAdaptorServer;import org.apache.commons.modeler.ManagedBean;import org.apache.commons.modeler.Registry;import javax.management.MBeanServer;import javax.management.ObjectName;import javax.management.modelmbean.ModelMBean;import java.io.InputStream;public class HelloAgent { public static void main(String[] args) throws Exception {// 需要将xml信息读入到Registry对象中 Registry registry = Registry.getRegistry(null,null); InputStream stream = HelloAgent.class.getResourceAsStream("mbeans-descriptors.xml"); registry.loadMetadata(stream); MBeanServer server = registry.getMBeanServer();// 之前是:MBeanServer server = ManagementFactory.getPlatformMBeanServer(); ManagedBean managed = registry.findManagedBean("Hello"); ObjectName helloName = new ObjectName(managed.getDomain()+":name=HelloWorld");// 以前是Hello hello = new Hello(); 为什么要多个createMBean?因为现在的写法没有写MBean,所以才要动态生成一个,以前就直接// 把new hello()注册到MBeanServer就可以了,server会自动找到它的HelloMBean接口文件。 ModelMBean hello = managed.createMBean(new Hello()); server.registerMBean(hello,helloName); ObjectName adapterName = new ObjectName(managed.getDomain()+":name = htmladapter,port=8082"); HtmlAdaptorServer adapter = new HtmlAdaptorServer(); server.registerMBean(adapter,adapterName); adapter.start(); }}
注意这里的Registry是指org.apache.commons.modeler.Registry,因为JMX自身也有一个Registry(java.rmi.registry.Registry)。通过Modeler组件提供的Registry对象,可以很方便的完成MBeanServer的创建。
运行效果和之前的一样,这里就不赘述了,有兴趣的小伙伴可以试一下。四种类型的MBean,前面所讲的都是常用的,现在还剩两种Open MBean就不讲述了,这里简单记录下Dynamic MBean。
Dynamic MBean不需要自定义MBean接口,只需要实现DynamicMBean接口即可,Dynamic MBean没有任何明显些在代码里的属性和方法,所有的属性和方法都是通过反射结合JMX提供的辅助元数据从而动态生成。 下面的代码中首先定义了一个属性name和一个方法print,之后在管理界面(localhost:8082)中点击print之后生成一个print1的方法。 Dynamic MBean的代码如下:package com.test.jmx.DynamicMBean;import javax.management.*;import java.lang.reflect.Constructor;import java.util.Iterator;/** * Created by hidden on 2016/10/9. */public class HelloDynamic implements DynamicMBean { private String name; private MBeanInfo mBeanInfo = null; private String className; private String description; private MBeanAttributeInfo[] attributes; private MBeanConstructorInfo[] constructors; private MBeanOperationInfo[] operations; MBeanNotificationInfo[] mBeanNotificationInfoArray; private void init(){ className = this.getClass().getName(); description = "Simple implementation of a dynamic MBean."; attributes = new MBeanAttributeInfo[1]; constructors = new MBeanConstructorInfo[1]; operations = new MBeanOperationInfo[1]; mBeanNotificationInfoArray = new MBeanNotificationInfo[0]; } private void buildDynamicMBean(){ Constructor[] thisConstructors = this.getClass().getConstructors(); constructors[0] = new MBeanConstructorInfo("HelloDynamic(): Constructs a HelloDynamic Object",thisConstructors[0]); attributes[0] = new MBeanAttributeInfo("name","java.lang.String","Name:name string.",true,true,false); MBeanParameterInfo[] params = null; operations[0] = new MBeanOperationInfo("print","print():print the name",params,"void",MBeanOperationInfo.INFO); mBeanInfo = new MBeanInfo(className,description,attributes,constructors,operations,mBeanNotificationInfoArray); } public HelloDynamic(){ init(); buildDynamicMBean(); } private void dynamicAddOperation(){ init(); operations = new MBeanOperationInfo[2]; buildDynamicMBean(); operations[1] = new MBeanOperationInfo("print1","print1():print the name",null,"void",MBeanOperationInfo.INFO); mBeanInfo = new MBeanInfo(className,description,attributes,constructors,operations,mBeanNotificationInfoArray); } @Override public Object getAttribute(String attribute) throws AttributeNotFoundException, MBeanException, ReflectionException { if (attribute == null) { return null; } if (attribute.equals("Name")) { return name; } return null; } @Override public void setAttribute(Attribute attribute) throws AttributeNotFoundException, InvalidAttributeValueException, MBeanException, ReflectionException { if (attribute == null) { return; } String Name = attribute.getName(); Object value = attribute.getValue(); try { if (Name.equals("Name")) { if (value == null) { name=null; } else if (Class.forName("java.lang.String").isAssignableFrom(value.getClass())) { name = (String) name; } } } catch (ClassNotFoundException e) { e.printStackTrace(); } } @Override public AttributeList getAttributes(String[] attributes) { if (attributes == null) { return null; } AttributeList resultList = new AttributeList();// if (attributes.length == 0) { // return resultList;// } for(int i=0;i
通过Agent调用Dynamic MBean:
package com.test.jmx.DynamicMBean;import com.sun.jdmk.comm.HtmlAdaptorServer;import javax.management.*;import java.lang.management.ManagementFactory;import java.util.concurrent.TimeUnit;public class HelloAgent { public static void main(String[] args) throws MalformedObjectNameException, NotCompliantMBeanException, InstanceAlreadyExistsException, MBeanRegistrationException { MBeanServer server = ManagementFactory.getPlatformMBeanServer(); ObjectName helloName = new ObjectName("MyMBean:name=helloDynamic"); HelloDynamic hello = new HelloDynamic(); server.registerMBean(hello,helloName); ObjectName adapterName = new ObjectName("MyMBean:name=htmladapter"); HtmlAdaptorServer adapter = new HtmlAdaptorServer(); server.registerMBean(adapter,adapterName); adapter.start(); }}
运行效果图如下:
运行结果:
Hello, null,this is HelloDynamic!这是动态增加的一个方法print1