java四种线程池

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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 #sfor (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() {@Overridepublic 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 #sfor (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() {@Overridepublic 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//#sthreadPool.schedule(new Runnable() {@Overridepublic 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//#sthreadPool.scheduleAtFixedRate(new Runnable() {@Overridepublic 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//#sthreadPool.scheduleWithFixedDelay(new Runnable() {@Overridepublic 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 #sfor (int i = 0; i < 1000; i++) {final int index=i;threadPool.execute(new Runnable() {@Overridepublic 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}}

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