注册时使用MBeanServer进行注册的操作，给定对应的mbean，mbeanServer会根据该bean实现的接口去寻找其对应的MBean定义。

 

 

MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();

        ControllerMBean controllerMBean = new ControllerBean();

        mbs.registerMBean(controllerMBean, new ObjectName("MyAppmbean:name=controller"));

 

在第一次运行时出现如下问题：

 

javax.management.NotCompliantMBeanException: jmx.ControllerBean: Class jmx.ControllerBean is not a JMX compliant MXBean

    at com.sun.jmx.mbeanserver.Introspector.throwException(Introspector.java:466)

    at com.sun.jmx.mbeanserver.Introspector.getMXBeanInterface(Introspector.java:357)

    at com.sun.jmx.mbeanserver.Introspector.checkCompliance(Introspector.java:166)

    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:317)

    at com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:522)

    at jmx.Main.main(Main.java:16)

 

经过分析JMX.isMXBeanInterface方法，可以看出，在registerMBean的时候，会根据当前类实现的接口列表，查找符合MXBean定义的接口，如果接口不符合MXBean的定义就会抛出上面的错误，如何使得接口满足MXBean类型，一种是接口名称以“MXBean”结尾，一种是加入@MXBean Annotation。

 

public static boolean isMXBeanInterface(Class<?> interfaceClass) {

        if (!interfaceClass.isInterface())

            return false;

        if (!Modifier.isPublic(interfaceClass.getModifiers()) &&

            !Introspector.ALLOW_NONPUBLIC_MBEAN) {

            return false;

        }

        MXBean a = interfaceClass.getAnnotation(MXBean.class);

        if (a != null)

            return a.value();

        return interfaceClass.getName().endsWith("MXBean");

        // We don't bother excluding the case where the name is

        // exactly the string "MXBean" since that would mean there

        // was no package name, which is pretty unlikely in practice.

    }

 

Spring与JMX的整合

 

 

对于标准的MBean来说，主要是通过MBeanExporter来实现的，比如上面我们提到的MBean，就可以通过配置mbServer以及mbean的方式管理MXBean：

 

<bean id="mbServer" class="org.springframework.jmx.export.MBeanExporter">

        <property name="autodetectModeName" value="AUTODETECT_ALL"/>

    </bean>

    <bean name="mydomain:myobj=MyObjectMBean" class="com.api.example.jmx.ControllerBean"/>

 

上面的配置中，MBeanExporter会查找本地MBean Server，指定的探测模式autodetectModeName为AUTODETECT_ALL，无需手动向MBean Server进行注册，便可以管理配置中的MBean对象。

 

 

@ManagedResource表示指定该类的实例作为MBean注册到MBean Server中，然后通过对属性和方法分别使用@ManagedAttribute和@ManagedOperation来指定暴露的属性和方法，

 

@Component

@ManagedResource(objectName = "org.springexample.jmx:name=ServerManager", description = "Server Manager")

public class ServerManagerImpl {

    private String serverName = "springServer";

    private boolean serverRunning = true;

    private int minPoolSize = 5;

    private int maxPoolSize = 10;

    @ManagedAttribute(description = "The server name.")

    public String getServerName() {

        return serverName;

    }

    @ManagedAttribute(description = "Server's running status.")

    public boolean isServerRunning() {

        return serverRunning;

    }

    @ManagedAttribute(description = "Whether or not the server is running.", currencyTimeLimit = 20, persistPolicy = "OnUpdate")

    public void setServerRunning(boolean serverRunning) {

        this.serverRunning = serverRunning;

    }

    @ManagedOperation(description = "Change db connection pool size.")

    @ManagedOperationParameters({

            @ManagedOperationParameter(name = "min", description = "Minimum pool size."),

            @ManagedOperationParameter(name = "max", description = "Maximum pool size.")

    })

    public int changeConnectionPoolSize(int minPoolSize, int maxPoolSize) {

        Assert.isTrue(minPoolSize > 0, "Minimum connection pool size must be larger than 0, min=" + minPoolSize);

        Assert.isTrue(maxPoolSize > minPoolSize, String.format("Minimum connection pool size must be smaller than maximum, min=%s, max=%s", minPoolSize, maxPoolSize));

        this.minPoolSize = minPoolSize;

        this.maxPoolSize = maxPoolSize;

        int diff = maxPoolSize - minPoolSize;

        Random random = new Random();

        int currentSize = (minPoolSize + random.nextInt(diff));

        return currentSize;

    }

}

 

基于spring基于注解的MBean管理可以针对一个普通的Java类，指定暴露的属性和方法，此时在spring applicationContext中声明的内容就要少很多，只需要声明扫描的package，以及mbean-export即可。

 

<context:component-scan base-package="com.api.example"/>

<context:mbean-export/>

 

这里我们就可以通过JVisualVM来简单地动态修改类似池化的一些配置，并使其生效

。