threadmonitorclient.java

jmx codeJava源码

package book.jmx.examples;

import javax.management.*;
import javax.management.monitor.*;
import java.util.List;

public class ThreadMonitorClient {

  private MBeanServer server  = null;
  private ObjectName threads  = null;
  private ObjectName monitor  = null;
  
  public void run() {

    // Find an agent from this JVM. Null argument will
    // return a list of all MBeanServer instances.
    List list = MBeanServerFactory.findMBeanServer(null);
    server    = (MBeanServer)list.iterator().next();

    try {
      // register the MBean reporting thread count
      threads = new ObjectName("Observable:type=Threads");
      server.registerMBean(new ThreadMonitor(), threads);
  
      // configure the monitor
      GaugeMonitor threadMon = new GaugeMonitor();
      threadMon.setObservedObject(threads);
      threadMon.setObservedAttribute("ThreadCount");
      threadMon.setGranularityPeriod(5 * 1000);
      threadMon.setNotifyHigh(true);
    
      threadMon.setThresholds(
          new Integer(30), new Integer(20)
      );
    
      // register the monitor
      monitor = new ObjectName("Monitor:type=Threads");
      server.registerMBean(threadMon, monitor);
      threadMon.start();

      server.addNotificationListener(
          monitor, new MonitorListener(), null, monitor
      ); 
    
      // test the monitor by creating 35 extra threads
      for (int i = 0; i < 35; ++i) {
        Thread thread = new Thread(new Runnable() {
            
            public void run() {
                try {
                    Thread.sleep(10000);
                }
                catch (Exception ignored) {}
            }
        });
        
        thread.start();
      }
            
    } catch (JMException e) {
      e.printStackTrace();
    }
  }

  class MonitorListener implements NotificationListener {
      
    public void handleNotification(Notification n, 
                                   Object handback) {
       
      MonitorNotification notif = (MonitorNotification)n;
        
      if (notif.getType().equals
       (MonitorNotification.THRESHOLD_HIGH_VALUE_EXCEEDED)
      ) {
      
        System.out.println(
            "Warning, Thread count exceeds " + 
            notif.getTrigger()
        );
        
        System.out.println(
            "Current Thread count = " + 
            notif.getDerivedGauge()
        );
      }
    }
  }
    
  //
  // Main method for the client. This will instantiate
  // an agent in the JVM.
  //
  public static void main(String[] args) {
    
    MBeanServer server = 
        MBeanServerFactory.createMBeanServer();
     
    new ThreadMonitorClient().run();
  }
}