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The "Example Application Exposing Internals Using JMX" page has been changed by NevenCvetkovic: https://wiki.apache.org/tomcat/Example%20Application%20Exposing%20Internals%20Using%20JMX?action=diff&rev1=1&rev2=2 - This is a placeholder for a simple web application that exposes internals using JMX. + Here's a simple application that illustrates exposing internals using JMX. + == Description == + Application contains: + * Web deployment descriptor (e.g. WEB-INF/web.xml) that describes the application (optional) + * JSP views: home.jsp and WEB-INF/views/view.jsp + * A counter (e.g. example.jmx.web.MyCounter) that can increment, get current count, reset counter and reset to a specific value. + * A servlet (e.g. example.jmx.web.CounterServlet) that calls counter and forwards to a view (e.g. WEB-INF/views/view.jsp) + * A servlet listener (e.g. example.jmx.web.RegisterMBeansListener), that registers the MBean to JMX MBeanServer + * An MBean interface (e.g. example.jmx.mbean.CounterMBean) that defines JMX attributes and operations, e.g. name, resetCounter, getCurrentCount, getCurrentTime + * An MBean implementation (e.g. example.jmx.mbean.Counter) that implements MBean interface + + == Code Examples == + + === example.jmx.web.MyCounter === + {{{ + package example.jmx.web; + + import java.util.concurrent.atomic.AtomicInteger; + + public class MyCounter { + + private static AtomicInteger counter = new AtomicInteger(0); + + public static int incrementAndGet() { + return counter.incrementAndGet(); + } + + public static int getCurrentCount() { + return counter.get(); + } + + public static void resetCounter() { + resetCounter(0); + } + + public static void resetCounter(int start) { + counter = new AtomicInteger(start); + } + + } + }}} + + === example.jmx.web.CounterServlet servlet === + {{{ + package example.jmx.web; + + import java.io.IOException; + + import javax.servlet.ServletException; + import javax.servlet.annotation.WebServlet; + import javax.servlet.http.HttpServlet; + import javax.servlet.http.HttpServletRequest; + import javax.servlet.http.HttpServletResponse; + + @WebServlet("/count") + public class CounterServlet extends HttpServlet { + + private static final long serialVersionUID = 886395215542306826L; + + @Override + protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + + request.setAttribute("COUNT", MyCounter.incrementAndGet()); + request.getRequestDispatcher("/WEB-INF/views/view.jsp").forward(request, response); + } + + } + }}} + + === example.jmx.web.RegisterMBeansListener web listener === + {{{ + package example.jmx.web; + + import java.lang.management.ManagementFactory; + + import javax.management.InstanceAlreadyExistsException; + import javax.management.InstanceNotFoundException; + import javax.management.MBeanRegistrationException; + import javax.management.MBeanServer; + import javax.management.MalformedObjectNameException; + import javax.management.NotCompliantMBeanException; + import javax.management.ObjectName; + import javax.servlet.ServletContextEvent; + import javax.servlet.ServletContextListener; + import javax.servlet.annotation.WebListener; + + import example.jmx.mbean.CounterMBean; + import example.jmx.mbean.Counter; + + @WebListener + public class RegisterMBeansListener implements ServletContextListener { + + private ObjectName objectName; + + public RegisterMBeansListener() { + } + + @Override + public void contextInitialized(ServletContextEvent sce) { + System.out.println("Registering MBean..."); + final MBeanServer server = ManagementFactory.getPlatformMBeanServer(); + try { + objectName = new ObjectName("JmxExampleApp:type=Counter"); + final CounterMBean mbean = new Counter(); + server.registerMBean(mbean, objectName); + System.out.println("MBean registered: " + objectName); + } catch (MalformedObjectNameException mone) { + mone.printStackTrace(); + } catch (InstanceAlreadyExistsException iaee) { + iaee.printStackTrace(); + } catch (MBeanRegistrationException mbre) { + mbre.printStackTrace(); + } catch (NotCompliantMBeanException ncmbe) { + ncmbe.printStackTrace(); + } + } + + @Override + public void contextDestroyed(ServletContextEvent sce) { + System.out.println("Unregistering MBean..."); + final MBeanServer server = ManagementFactory.getPlatformMBeanServer(); + try { + objectName = new ObjectName("JmxExampleApp:type=Counter"); + server.unregisterMBean(objectName); + System.out.println("MBean unregistered: " + objectName); + } catch (MalformedObjectNameException mone) { + mone.printStackTrace(); + } catch (MBeanRegistrationException mbre) { + mbre.printStackTrace(); + } catch (InstanceNotFoundException infe) { + infe.printStackTrace(); + } + } + + } + }}} + + === example.jmx.mbean.CounterMBean interface === + {{{ + package example.jmx.mbean; + + import java.util.Date; + + public interface CounterMBean { + void resetCounter(); + void resetCounter(int start); + int getCurrentCount(); + Date getCurrentTime(); + long getCurrentTimeMilis(); + } + }}} + + === example.jmx.mbean.Counter implementation === + {{{ + package example.jmx.mbean; + + import java.util.Date; + + import example.jmx.web.MyCounter; + + public class Counter implements CounterMBean { + + private String name; + + public Counter() { + this.name = "InitialName"; + } + + public String getName() { + return name; + } + public void setName(String name) { + this.name = name; + } + + @Override + public void resetCounter() { + MyCounter.resetCounter(); + } + + @Override + public void resetCounter(int start) { + MyCounter.resetCounter(start); + } + + @Override + public int getCurrentCount() { + return MyCounter.getCurrentCount(); + } + + @Override + public Date getCurrentTime() { + return new Date(); + } + + @Override + public long getCurrentTimeMilis() { + return System.currentTimeMillis(); + } + + } + }}} + + + == Download == + Download [[attachment:JmxExample.war|JmxExample.war]] (with source code). + --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org For additional commands, e-mail: dev-h...@tomcat.apache.org
