要监控Java ThreadPoolExecutor的状态，您可以使用以下方法：
beforeExecute()和afterExecute()方法。在这些方法中，您可以记录线程池的状态信息，例如活动线程数、任务队列大小等。import java.util.concurrent.*; public class CustomThreadPoolExecutor extends ThreadPoolExecutor { public CustomThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue) { super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue); } @Override protected void beforeExecute(Thread t, Runnable r) { System.out.println("线程 " + t.getName() + " 开始执行任务 " + r.toString()); super.beforeExecute(t, r); } @Override protected void afterExecute(Runnable r, Throwable t) { System.out.println("线程 " + Thread.currentThread().getName() + " 结束执行任务 " + r.toString()); super.afterExecute(r, t); } public static void main(String[] args) { CustomThreadPoolExecutor executor = new CustomThreadPoolExecutor(3, 5, 60, TimeUnit.SECONDS, new LinkedBlockingQueue<>(10)); for (int i = 0; i < 20; i++) { executor.execute(new Task("任务 " + i)); } executor.shutdown(); } } class Task implements Runnable { private String name; public Task(String name) { this.name = name; } @Override public void run() { // 执行任务逻辑 } } 首先，创建一个实现ThreadPoolExecutor的类，并重写newTaskFor()方法以返回一个实现了RunnableScheduledFuture接口的自定义任务类。然后，创建一个MBean类，用于暴露线程池的状态信息。最后，在主类中注册MBean并启动JMX代理。
import java.util.concurrent.*; import javax.management.*; import javax.management.remote.*; public class ThreadPoolExecutorWithJMX extends ThreadPoolExecutor { public ThreadPoolExecutorWithJMX(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue) { super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue); } @Override protected <T> RunnableScheduledFuture<T> newTaskFor(Callable<T> callable) { return new CustomScheduledFutureTask<>(callable); } public static void main(String[] args) throws Exception { ThreadPoolExecutorWithJMX executor = new ThreadPoolExecutorWithJMX(3, 5, 60, TimeUnit.SECONDS, new LinkedBlockingQueue<>(10)); MBeanServer mbs = ManagementFactory.getPlatformMBeanServer(); ObjectName name = new ObjectName("com.example:type=ThreadPoolExecutor"); mbs.registerMBean(executor, name); // 提交任务并监控线程池状态 for (int i = 0; i < 20; i++) { executor.execute(new Task("任务 " + i)); } // 关闭线程池 executor.shutdown(); // 连接到JMX代理并获取线程池状态信息 JMXServiceURL url = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://localhost:1099/jmxrmi"); JMXConnector jmxConnector = JMXConnectorFactory.connect(url); JMXServiceConnection connection = jmxConnector.getMBeanConnection(); AttributeList attributes = connection.getAttributes(name, new String[]{"activeCount", "corePoolSize", "maximumPoolSize", "taskCount", "queueCapacity"}); for (Object attr : attributes) { System.out.println(attr); } } } class CustomScheduledFutureTask<T> extends FutureTask<T> implements RunnableScheduledFuture<T> { public CustomScheduledFutureTask(Callable<T> callable) { super(callable); } @Override public void run() { super.run(); } } class Task implements Runnable { private String name; public Task(String name) { this.name = name; } @Override public void run() { // 执行任务逻辑 } } 运行上述代码后，您可以使用JConsole或VisualVM等工具连接到JMX代理，然后查看线程池的状态信息，如活动线程数、核心线程数、最大线程数、任务队列容量等。
