JAVA 查看線程池狀態

//<!-- 需要依賴 pool 對象池 -->
//<dependency>
//<groupId>org.apache.commons</groupId>
//<artifactId>commons-pool2</artifactId>
//</dependency>

import org.apache.commons.lang3.concurrent.BasicThreadFactory;

import java.util.TimerTask;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;


/**
 * 線程池狀態查看
 */
public class TestThread {
    private static ScheduledExecutorService executor = new ScheduledThreadPoolExecutor(10, new BasicThreadFactory.Builder().namingPattern("schedule-pool-%d").daemon(true).build());

    public static void main(String[] args) {
        executor.schedule(newTask("aaa"), 10, TimeUnit.MILLISECONDS);
        executor.schedule(newTask("bbb"), 10, TimeUnit.MILLISECONDS);
        executor.schedule(newTask("ccc"), 10, TimeUnit.MILLISECONDS);
        executor.schedule(newTask("一秒"), 1000, TimeUnit.MILLISECONDS);
        executor.schedule(newTask("5秒"), 5000, TimeUnit.MILLISECONDS);
        executor.schedule(badTask(), 10, TimeUnit.MILLISECONDS);


        while (getPoolInfo((ThreadPoolExecutor) executor) > 0) {
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    private static int getPoolInfo(ThreadPoolExecutor tpe) {
        System.out.println();
        int queueSize = tpe.getQueue().size();
        System.out.println("當前排隊線程數：" + queueSize);

        int activeCount = tpe.getActiveCount();
        System.out.println("當前活動線程數：" + activeCount);

        long completedTaskCount = tpe.getCompletedTaskCount();
        System.out.println("執行完成線程數：" + completedTaskCount);

        long taskCount = tpe.getTaskCount();
        System.out.println("總線程數：" + taskCount);

        //線程池中當前線程的數量，爲0時意味着沒有任何線程，線程池會終止，此值不會超過MaximumPoolSize
        System.out.println("當前線程的數量:" + tpe.getPoolSize());

        //線程池的初始線程數量(當沒有任務提交，或提交任務數小於此值值，實際並不會產生那麼多線程數)
        System.out.println("線程池的初始線程數量:" + tpe.getCorePoolSize());

        //線程池可允許最大的線程數
        System.out.println("線程池可允許最大的線程數" + tpe.getMaximumPoolSize());
        tpe.getLargestPoolSize();

        return queueSize;
    }

    private static TimerTask newTask(String str) {
        return new TimerTask() {
            @Override
            public void run() {
                System.err.println("線程:" + Thread.currentThread().getName() + " = " + str);
            }
        };
    }

    private static TimerTask badTask() {
        return new TimerTask() {
            @Override
            public void run() {
                System.err.println("壞的線程:" + Thread.currentThread().getName());
                //對於異常一定要捕獲，否則沒有任何提示
                try {
                    int i = 1 / 0;
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        };
    }
}