线程池的使用

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个人笔记常用的四种线程池

import java.util.Random;import java.util.concurrent.Callable;import java.util.concurrent.ExecutionException;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.Future;/** * 生成一个有5个线程的线程池   提交20个任务  看5个线程中的哪个线程来处理任务 * @author zhangkun * */public class MyClass8 {public static void main(String[] args) throws InterruptedException, ExecutionException {//新建一个5个线程的线程池ExecutorService threadPool = Executors.newFixedThreadPool(5);Future<Integer> result = null;try {for (int i = 0; i < 20; i++) {//给线程池提交任务，看那个线程会对其进行处理result = threadPool.submit(new Callable<Integer>() {@Overridepublic Integer call() throws Exception {System.out.print(Thread.currentThread().getName()+"-------");return new Random().nextInt(50);}});System.out.println(result.get()+"---"+ i);}} catch (Exception e) {e.printStackTrace();}finally{//关闭线程池threadPool.shutdown();}}}

import java.util.Random;import java.util.concurrent.Callable;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.Future;/** * 单线程的线程池 * @author Administrator * */public class MyClass9 {public static void main(String[] args) {//新建一个只有一个线程的线程池ExecutorService threadPool = Executors.newSingleThreadExecutor();Future<Integer> result = null;try {for (int i = 0; i < 20; i++) {//给线程池提交任务，看那个线程会对其进行处理  这次线程池中只有一个线程result = threadPool.submit(new Callable<Integer>() {@Overridepublic Integer call() throws Exception {System.out.print(Thread.currentThread().getName()+"-------");return new Random().nextInt(50);}});System.out.println(result.get()+"---"+ i);}} catch (Exception e) {e.printStackTrace();}finally{//关闭线程池threadPool.shutdown();}}}

import java.util.Random;import java.util.concurrent.Callable;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.Future;/** * 新建一个没有固定数量个线程的线程池   会根据往此线程池提交的任务数量，动态生成线程的个数，  当现有线程忙不过来就会在线程池中再生成一个线程 * @author Administrator * */public class MyClass10 {public static void main(String[] args) {//新建一个没有固定数量个线程的线程池   会根据往此线程池提交的任务数量，动态生成线程的个数，  当现有线程忙不过来就会在线程池中再生成一个线程ExecutorService threadPool = Executors.newCachedThreadPool();Future<Integer> result = null;try {for (int i = 0; i < 20; i++) {//给线程池提交任务，看那个线程会对其进行处理result = threadPool.submit(new Callable<Integer>() {@Overridepublic Integer call() throws Exception {Thread.sleep(3000);System.out.print(Thread.currentThread().getName()+"-------");return new Random().nextInt(50);}});System.out.println(result.get()+"---"+ i);}} catch (Exception e) {e.printStackTrace();}finally{//关闭线程池threadPool.shutdown();}}}

import java.util.Random;import java.util.concurrent.Callable;import java.util.concurrent.Executors;import java.util.concurrent.Future;import java.util.concurrent.ScheduledExecutorService;import java.util.concurrent.TimeUnit;/** * 该代码可以让线程在指定的延时之后执行 * @author ZhangKun * */public class MyClass11 {public static void main(String[] args) {//新建一个5个线程的线程池ScheduledExecutorService threadPool = Executors.newScheduledThreadPool(5);Future<Integer> result = null;try {for (int i = 0; i < 20; i++) {//给线程池提交任务，看那个线程会对其进行处理/** 方法api    创建并执行在给定延迟后启用的 ScheduledFuture。 * 第一个参数     New一个callable匿名内部类 * 第二个参数    时间长度 * 第三个参数   时间长度的单位（枚举变量） 天，小时，分钟，等 */result = threadPool.schedule(new Callable<Integer>() {@Overridepublic Integer call() throws Exception {System.out.print(Thread.currentThread().getName()+"-------");return new Random().nextInt(50);}}, 3, TimeUnit.SECONDS);System.out.println(result.get()+"---");}} catch (Exception e) {e.printStackTrace();}finally{//关闭线程池threadPool.shutdown();}}}

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