JMX之模型MBean

標準MBean所暴露的屬性，操作，通知都是固定不變的，都固化在ClassNameMBean這個接口中，靈活度不足。

動態Mbean所暴露的特性是運行時確立，靈活度足夠，但編碼困難，因爲你需要編碼實現每一個屬性，操作與通知。

模型Mbean也是一種動態Mbean，能夠使你更快的編寫動態MBean.

模型MBean的封裝類RequiredModelMBean實現了ModelMBean接口,而ModelMBean接口繼承自DynamicMBean，所以說模型Mbean也是一種動態Mbean。

首先定義需要管理的資源:

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~!!!");
    }
}

測試類:

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與HelloWorkShadow還沒有任何關係，去掉1，2兩行註釋，你會發現ModelMBeanAttributeInfo的描述子用來存儲了這個值（代碼中，ModelMBeanAttributeInfo的最後一個參數，我設了null,JDK會爲之創建一個默認的描述子）。

 

如何把對MBean的操作轉移動對HelloWordShadow的操作，以達到我們管是資源的目的。

第一步爲ModelMBeanAttributeInfo對像添加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"));
}

運行結果：

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

guojianjun

發現並沒有起作用。剛纔說到ModelMBeanAttributeInfo用了默認的描述子，我們不防給

添加一個描述子:

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，直接報錯：Operation setName not in ModelMBeanInfo。

但這也說明是用描述子設定set方法是正確的。這樣我們需要在ModelMBeanInfo中聲明setName操作,getName一樣: 

//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"));

仍然報錯： managedResource for invoke setName is null

managedResource是什麼？就是我們需要管理的對像資源，在這裏當然是HelloWordShadow對象，終於扯上關係了。那就構造一個HelloWordShadow對象:

      .....
      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"));

運行輸出：

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。說了這麼多，那構造函數ModelMBeanAttributeInfo("name",         "pepole name",getMethod, setMethod,nameDesc);裏的getMethod, setMethod方法有什麼用呢，我覺得好像沒什麼用，只是用來確認屬性類型，可讀可寫情況。（個人觀點）

最後就是把這個MBean註冊到MBeanServer中管理,用Jconsole就可以看到了：

ms.registerMBean(rmm, new ObjectName(

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

(待續)