java四种线程池

1、newCachedThreadPool

package com.vxichina.cluster.persistence.thread.pool;

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

/**
 * 第一种线程池newCachedThreadPool
 * 创建一个可缓存线程池，如果线程池长度超过处理需要，可灵活回收空闲线程，若无可回收，则新建线程。
 * @author admin
 *
 */
public class ThreadPoolOne {

	public static void main(String[] args) {
		ExecutorService threadPool=Executors.newCachedThreadPool();//理论上有无限个线程，实际使用时会重复利用已有的空闲线程
		//for #s
		for (int i = 0; i < 100; i++) {
			final int index=i;
			//System.out.println("for循环中index的值="+index);
			try {
				Thread.sleep(i*100);//触发操作系统立刻重新进行一次CPU竞争
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			threadPool.execute(new Runnable() {
				
				@Override
				public void run() {
					System.out.println("index的值="+index+",  当前线程：id="+Thread.currentThread().getId()+",  name="+Thread.currentThread().getName());
				}
			});
			
		}
		//for #e
	}
}

2、newFixedThreadPool

package com.vxichina.cluster.persistence.thread.pool;

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

/**
 * 第一种线程池newFixedThreadPool
 * 创建一个定长线程池，可控制线程最大并发数，超出的线程会在队列中等待。
 * @author admin
 *
 */
public class ThreadPoolTwo {

	public static void main(String[] args) {
		ExecutorService threadPool=Executors.newFixedThreadPool(3);//只设置3个线程
		//for #s
		for (int i = 0; i < 1000; i++) {
			final int index=i;
			//System.out.println("for循环中index的值="+index);
			threadPool.execute(new Runnable() {
				
				@Override
				public void run() {
					System.out.println("index的值="+index+",  当前线程：id="+Thread.currentThread().getId()+",  name="+Thread.currentThread().getName());
					try {
						Thread.sleep(3000);//触发操作系统立刻重新进行一次CPU竞争
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
			});
			
		}
		//for #e
	}
}

3、newScheduledThreadPool

package com.vxichina.cluster.persistence.thread.pool;

import java.util.Calendar;
import java.util.Date;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

/**
 * 第一种线程池newScheduledThreadPool
 * 创建一个定长线程池，支持定时及周期性任务执行。
 * @author admin
 *
 */
public class ThreadPoolThree {

	public static void main(String[] args) {
		//ScheduledExecutorService比Timer更安全，功能更强大
		ScheduledExecutorService threadPool=Executors.newScheduledThreadPool(3);//只设置3个线程
		//#s
		threadPool.schedule(new Runnable() {
			
			@Override
			public void run() {
				System.out.println("我是延迟5秒后执行的哦");
			}
		}, 5, TimeUnit.SECONDS);//表示延迟5秒执行
		//#e
		
		//#s
		threadPool.scheduleAtFixedRate(new Runnable() {
			
			@Override
			public void run() {
				System.out.println("我是延迟5秒后每2秒执行一回"+Calendar.getInstance().getTime().getHours()+":"+Calendar.getInstance().getTime().getMinutes()+":"+Calendar.getInstance().getTime().getSeconds());
			}
		}, 5, 2, TimeUnit.SECONDS);//延迟5秒后每2秒执行一次
		//#e
		
		//#s
		threadPool.scheduleWithFixedDelay(new Runnable() {
			
			@Override
			public void run() {
				System.out.println("输出"+Calendar.getInstance().getTime().getHours()+":"+Calendar.getInstance().getTime().getMinutes()+":"+Calendar.getInstance().getTime().getSeconds());
			}
		}, 2, 5, TimeUnit.SECONDS);//初始延迟2秒后面每个延迟5秒执行
		//#e
	}
}

4、newSingleThreadExecutor

package com.vxichina.cluster.persistence.thread.pool;

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

/**
 * 第一种线程池newSingleThreadExecutor
 * 创建一个单线程化的线程池，它只会用唯一的工作线程来执行任务，保证所有任务按照指定顺序(FIFO, LIFO, 优先级)执行。
 * @author admin
 *
 */
public class ThreadPoolFour {

	public static void main(String[] args) {
		ExecutorService threadPool=Executors.newSingleThreadExecutor();//单一线程，相当于顺序执行各个任务
		//for #s
		for (int i = 0; i < 1000; i++) {
			final int index=i;
			threadPool.execute(new Runnable() {
				
				@Override
				public void run() {
					System.out.println("index的值="+index+",  当前线程：id="+Thread.currentThread().getId()+",  name="+Thread.currentThread().getName());
					try {
						Thread.sleep(1000);//触发操作系统立刻重新进行一次CPU竞争
					} catch (Exception e) {
						e.printStackTrace();
					}
				}
			});
			
		}
		//for #e
	}
}