21丨Tomcat：中间件监控及常用计数器解析

import javax.management.MBeanServerConnection;
import javax.management.ObjectName;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXServiceURL;
import java.io.IOException;

public class TomcatMonitor {

    public static void main(String[] args) throws Exception {
        // 配置Tomcat JMX服务URL
        String jmxURL = "service:jmx:rmi:///jndi/rmi://localhost:9004/jmxrmi";
        JMXServiceURL serviceURL = new JMXServiceURL(jmxURL);

        // 连接到JMX服务器
        JMXConnector connector = JMXConnectorFactory.connect(serviceURL, null);
        MBeanServerConnection mbsc = connector.getMBeanServerConnection();

        // 通过JMX查询MBean，获取Tomcat的各种计数器
        ObjectName threads = new ObjectName("Catalina:type=ThreadPool,name=\"http-nio-8080\"");
        Integer maxThreads = (Integer) mbsc.getAttribute(threads, "maxThreads");
        Integer currentThreadCount = (Integer) mbsc.getAttribute(threads, "currentThreadCount");
        System.out.println("Max Threads: " + maxThreads);
        System.out.println("Current Threads: " + currentThreadCount);

        // ... 可以添加更多的MBean查询来获取其他计数器信息，如JVM内存使用情况、GC频率等

        // 关闭JMX连接
        connector.close();
    }
}