JMX之模型MBean

标准MBean所暴露的属性，操作，通知都是固定不变的，都固化在ClassNameMBean这个接口中，灵活度不足。

动态Mbean所暴露的特性是运行时确立，灵活度足够，但编码困难，因为你需要编码实现每一个属性，操作与通知。

模型Mbean也是一种动态Mbean，能够使你更快的编写动态MBean.

模型MBean的封装类RequiredModelMBean实现了ModelMBean接口,而ModelMBean接口继承自DynamicMBean，所以说模型Mbean也是一种动态Mbean。

首先定义需要管理的资源:

package guojje.jmx;

import javax.management.NotificationBroadcasterSupport;

public class HelloWordShadow extends NotificationBroadcasterSupport{

    private String name = "anranran";
    public HelloWordShadow(String name){
        this.name = name;
    }

    public String getName(){
        System.out.println("invoke getName method!!");
        return name;
    }

    public void setName(String name){
        System.out.println("invoke setName method!!");
        this.name = name;
    }

    public void Say(){
        System.out.println("hi~!!!");
    }
}

测试类:

package guojje.jmx;
public class Main {
    public static void main(String args[]) throws Exception {
        JMXServiceURL jUrl = new JMXServiceURL("iiop", "192.168.1.61", 9998,
                "/jndi/rmi://localhost:9999/guojje");
        MBeanServer ms = MBeanServerFactory.createMBeanServer();
        JMXConnectorServer cs = JMXConnectorServerFactory
                .newJMXConnectorServer(jUrl, null, ms);
        cs.start();
        System.out.println("jmx address:" + cs.getAddress());

        exeHelloWordShadow(ms);
    }
private static void exeHelloWordShadow(MBeanServer ms) throws Exception {
        RequiredModelMBean rmm = new RequiredModelMBean();
        //add a property called 'name'
        ModelMBeanAttributeInfo nameAttr = new ModelMBeanAttributeInfo("name","java.lang.String",
                "pepole name",true, true, false,null);

        ModelMBeanInfo mmInfo = new ModelMBeanInfoSupport(RequiredModelMBean.class.toString(), "Jmx demo", new ModelMBeanAttributeInfo[]{nameAttr}, null, null, null);
        rmm.setModelMBeanInfo(mmInfo);
    //System.out.println(nameAttr.getDescriptor().getFieldValue("value"));//1
        rmm.setAttribute(new Attribute("name", "guojianjun"));
        System.out.println(rmm.getAttribute("name"));
    //System.out.println(nameAttr.getDescriptor().getFieldValue("value")); //2
}

目前name与HelloWorkShadow还没有任何关系，去掉1，2两行注释，你会发现ModelMBeanAttributeInfo的描述子用来存储了这个值（代码中，ModelMBeanAttributeInfo的最后一个参数，我设了null,JDK会为之创建一个默认的描述子）。
 

如何把对MBean的操作转移动对HelloWordShadow的操作，以达到我们管是资源的目的。

第一步为ModelMBeanAttributeInfo对像添加get,set方法.

private static void exeHelloWordShadow(MBeanServer ms) throws Exception {
        RequiredModelMBean rmm = new RequiredModelMBean();
        Method getMethod = HelloWordShadow.class.getMethod("getName",
                new Class[] {});
        Method setMethod = HelloWordShadow.class.getMethod("setName",
                new Class[] {String.class});
        //add a property called 'name'
        ModelMBeanAttributeInfo nameAttr = new ModelMBeanAttributeInfo("name",
                "pepole name",getMethod, setMethod,null);



        ModelMBeanInfo mmInfo = new ModelMBeanInfoSupport(RequiredModelMBean.class.toString(), "Jmx demo", new ModelMBeanAttributeInfo[]{nameAttr}, null, null, null);
        rmm.setModelMBeanInfo(mmInfo);

        rmm.setAttribute(new Attribute("name", "guojianjun"));
        System.out.println(rmm.getAttribute("name"));
}

运行结果：

jmx address:service:jmx:iiop://192.168.1.61:9998/jndi/rmi://localhost:9999/guojje

guojianjun

发现并没有起作用。刚才说到ModelMBeanAttributeInfo用了默认的描述子，我们不防给

添加一个描述子:

private static void exeHelloWordShadow(MBeanServer ms) throws Exception {
      .....
      Descriptor nameDesc = new DescriptorSupport();
        nameDesc.setField("name", "Name");//must be setted
        nameDesc.setField("descriptorType", "attribute");//must be setted
        nameDesc.setField("displayName", "Name");
        nameDesc.setField("getMethod", "getName");
        nameDesc.setField("setMethod", "setName");
        //add a property called 'name'
        ModelMBeanAttributeInfo nameAttr = new ModelMBeanAttributeInfo("name",
                "pepole name",getMethod, setMethod,nameDesc);

        ModelMBeanInfo mmInfo = new ModelMBeanInfoSupport(null, "Jmx demo", new ModelMBeanAttributeInfo[]{nameAttr}, null, null, null);
        rmm.setModelMBeanInfo(mmInfo);

        rmm.setAttribute(new Attribute("name", "guojianjun"));
        System.out.println(rmm.getAttribute("name"));
}

更糟糕，直接报错：Operation setName not in ModelMBeanInfo。

但这也说明是用描述子设定set方法是正确的。这样我们需要在ModelMBeanInfo中声明setName操作,getName一样: 

//add a property called 'name'
        ModelMBeanAttributeInfo nameAttr = new ModelMBeanAttributeInfo("name",
                "pepole name",getMethod, setMethod,nameDesc);

         //parameter is not necessary
         ModelMBeanOperationInfo getName = new ModelMBeanOperationInfo(//
                    "getName", //
                    "get name attribute", //
                    null, //
                    "java.lang.String", //
                    MBeanOperationInfo.ACTION, //
                    null//
                  );

         MBeanParameterInfo mParam = new MBeanParameterInfo("name", "java.lang.String", "set name methord param");

         ModelMBeanOperationInfo setName = new ModelMBeanOperationInfo(//
                    "setName", //
                    "set name attribute", //
                    new MBeanParameterInfo[]{mParam}, //
                    null, //
                    MBeanOperationInfo.ACTION, //
                    null//
          );

        ModelMBeanInfo mmInfo = new ModelMBeanInfoSupport(null, "Jmx demo", new ModelMBeanAttributeInfo[]{nameAttr},
                null , new ModelMBeanOperationInfo[]{getName,setName}, null);
        rmm.setModelMBeanInfo(mmInfo);

        rmm.setAttribute(new Attribute("name", "guojianjun"));
        System.out.println(rmm.getAttribute("name"));

仍然报错： managedResource for invoke setName is null

managedResource是什么？就是我们需要管理的对像资源，在这里当然是HelloWordShadow对象，终于扯上关系了。那就构造一个HelloWordShadow对象:

      .....
      ModelMBeanInfo mmInfo = new ModelMBeanInfoSupport(RequiredModelMBean.class.toString(), "Jmx demo", new ModelMBeanAttributeInfo[]{nameAttr},
                null , new ModelMBeanOperationInfo[]{getName,setName}, null);
        rmm.setModelMBeanInfo(mmInfo);

        HelloWordShadow hw = new HelloWordShadow("miniName");
        rmm.setManagedResource(hw, "ObjectReference");

        rmm.setAttribute(new Attribute("name", "guojianjun"));
        System.out.println(rmm.getAttribute("name"));

运行输出：

jmx address:service:jmx:iiop://192.168.1.61:9998/jndi/rmi://localhost:9999/guojje

invoke getName method!!

invoke setName method!!

invoke getName method!!

guojianjun

OK,成功。说了这么多，那构造函数ModelMBeanAttributeInfo("name",         "pepole name",getMethod, setMethod,nameDesc);里的getMethod, setMethod方法有什么用呢，我觉得好像没什么用，只是用来确认属性类型，可读可写情况。（个人观点）

最后就是把这个MBean注册到MBeanServer中管理,用Jconsole就可以看到了：

ms.registerMBean(rmm, new ObjectName(

       "guojje:type=notification,name=hello"));

(待续)