如何监控java Executor执行器的运行状态

要监控Java Executor执行器的运行状态，可以使用以下方法：

1. 使用ThreadPoolExecutor类：

如果你使用的是ThreadPoolExecutor，可以通过以下方法监控其运行状态：

• getActiveCount()：返回正在执行任务的线程的大概数量。
• getCompletedTaskCount()：返回已完成执行的任务的大概总数。
• getTaskCount()：返回计划执行的任务的大概总数。
• getPoolSize()：返回线程池的大小。
• getLargestPoolSize()：返回线程池中曾经同时存在的最大线程数。
• getQueue().size()：返回等待执行的任务队列的大小。

示例：

import java.util.concurrent.Executors;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ThreadPoolMonitor {
    public static void main(String[] args) throws InterruptedException {
        ThreadPoolExecutor executor = (ThreadPoolExecutor) Executors.newFixedThreadPool(5);

        for (int i = 0; i < 10; i++) {
            executor.submit(() -> {
                try {
                    TimeUnit.SECONDS.sleep(1);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            });
        }

        System.out.println("Active Threads: " + executor.getActiveCount());
        System.out.println("Completed Tasks: " + executor.getCompletedTaskCount());
        System.out.println("Total Tasks: " + executor.getTaskCount());
        System.out.println("Pool Size: " + executor.getPoolSize());
        System.out.println("Largest Pool Size: " + executor.getLargestPoolSize());
        System.out.println("Queue Size: " + executor.getQueue().size());

        executor.shutdown();
    }
}

2. 使用ScheduledExecutorService定期监控：

你可以使用ScheduledExecutorService定期输出线程池的状态信息。

示例：

import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ThreadPoolMonitor {
    public static void main(String[] args) {
        ThreadPoolExecutor executor = (ThreadPoolExecutor) Executors.newFixedThreadPool(5);
        ScheduledExecutorService monitor = Executors.newScheduledThreadPool(1);

        monitor.scheduleAtFixedRate(() -> {
            System.out.println("Active Threads: " + executor.getActiveCount());
            System.out.println("Completed Tasks: " + executor.getCompletedTaskCount());
            System.out.println("Total Tasks: " + executor.getTaskCount());
            System.out.println("Pool Size: " + executor.getPoolSize());
            System.out.println("Largest Pool Size: " + executor.getLargestPoolSize());
            System.out.println("Queue Size: " + executor.getQueue().size());
        }, 0, 5, TimeUnit.SECONDS);

        for (int i = 0; i < 10; i++) {
            executor.submit(() -> {
                try {
                    TimeUnit.SECONDS.sleep(1);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            });
        }

        executor.shutdown();
        monitor.shutdown();
    }
}

这样，每隔5秒，程序会输出线程池的状态信息。你可以根据需要调整监控间隔。