java - 管理 Java 虚拟机的 JMX 功能 Out-Of-Box

Question

在研究JMX时，我看到它的一个重要特性是它可以管理JVM本身，但我不明白它在什么意义上可以管理JVM。那么任何人都可以用一些例子来详细说明这一点吗？

Answer 1

您可以很容易地亲眼看到这一点。

• 第 1 步:下载 JConsole
• 第 2 步:启动 Java 进程(Java 5 或更高版本)
• 第 3 步:使用 JConsole 连接到您的 Java 进程
• 第 4 步:查看用于触发堆转储事件、垃圾收集请求、线程信息、加载的类等的 MBean

特别有趣的是，您可以编写代码来访问正在运行的 Java 程序的 MBean:

There are three different ways to access the management interfaces. Call the methods in the MXBean directly within the same Java virtual machine.

RuntimeMXBean mxbean = ManagementFactory.getRuntimeMXBean();

   // Get the standard attribute "VmVendor"    String vendor = mxbean.getVmVendor();

Go through a MBeanServerConnection connecting to the platform MBeanServer of a running virtual machine.

MBeanServerConnection mbs;

   // Connect to a running JVM (or itself) and get MBeanServerConnection  // that has the JVM MXBeans registered in it    ...

   try {
       // Assuming the RuntimeMXBean has been registered in mbs
       ObjectName oname = new ObjectName(ManagementFactory.RUNTIME_MXBEAN_NAME);

       // Get standard attribute "VmVendor"
       String vendor = (String) mbs.getAttribute(oname, "VmVendor");   } catch (....) {
       // Catch the exceptions thrown by ObjectName constructor
       // and MBeanServer.getAttribute method
       ...    }

Use MXBean proxy.

MBeanServerConnection mbs;

   // Connect to a running JVM (or itself) and get MBeanServerConnection  // that has the JVM MBeans registered in it    ...

   // Get a MBean proxy for RuntimeMXBean interface    RuntimeMXBean proxy = 
       ManagementFactory.newPlatformMXBeanProxy(mbs,
                                                ManagementFactory.RUNTIME_MXBEAN_NAME,
                                                RuntimeMXBean.class);    // Get standard attribute "VmVendor"     String vendor = proxy.getVmVendor();

另请参阅The Java Language Management API