java-单例模式的java连接池

package com.dawning.gridview.app.resourcemanagement.service.servicemanagement.discoverresourceutil;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * 线程池单例
 * @class SingletonTheadPool
 * @date 2015-7-7 下午3:29:04
 * @author wanghc
 */
public class SingletonTheadPool {
    /**
     * 单例
     */
    private static class SingletonHolder{
        private static final ExecutorService MYPOOL = Executors.newFixedThreadPool(2);
    }

    private SingletonTheadPool(){};

    public static final ExecutorService getSingletonTheadPool(){

        return SingletonHolder.MYPOOL;
    }

}

 // 获取当前线程池中活跃的线程数

将ExecutorService转换为ThreadPoolExecutor,ThreadPoolExecutor有方法 getActiveCount()可以得到当前活动线程数
int threadCount = ((ThreadPoolExecutor)MYPOOL).getActiveCount();