线程创建的三种方式

一、继承Thread

package com.caiweiwei.lianxi.controller;
import java.util.Random;
public class ThreadTest {
    public static void main(String[] args) {
        Runable lufei=new Runable();
        lufei.setName("路飞");//设置线程名称
        Runable caimou=new Runable();
        caimou.setName("蔡某");
        Runable shashibiye=new Runable();
        shashibiye.setName("莎士比亚");
        //线程启动
        lufei.start();
        caimou.start();
        shashibiye.start();
    }
}
class Runable extends Thread{
    //实现run方法
    @Override
    public void run() {
        Integer speed= new Random().nextInt(100);
        for (int i = 0; i <=100 ; i++) {
            try {
                Thread.sleep(1000);//当前线程休眠一秒
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(this.getName()+"已前进"+(i*speed)+"米");
        }
    }
}

二、实现Runnable接口

package com.caiweiwei.lianxi.controller;

import java.util.Random;

public class ThreadTest2 {
    public static void main(String[] args) {
        Runner2 liuxiang = new Runner2();
        Thread thread1 = new Thread(liuxiang);
        thread1.setName("路飞");

        Thread laoqi = new Thread(new Runner2());
        laoqi.setName("蔡某");

        Thread op = new Thread(new Runner2());
        op.setName("莎士比亚");

        thread1.start();
        laoqi.start();
        op.start();
    }
}
class Runner2 implements Runnable{

    @Override
    public void run() {
        Integer speed=new Random().nextInt(100);
        for (int i = 0; i <100 ; i++) {
            try {
                Thread.sleep(1000);//当前线程休眠1秒
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            //Thread.currentThread()用于获取当前执行的线程对象
            //在Runnable中是无法使用this获取到当前线程对象的
            System.out.println(Thread.currentThread().getName() + "已前进" + (i * speed) + "米（" + speed + "米/秒)");
        }
    }
}

三、实现Callable接口

package com.caiweiwei.lianxi.controller;

import java.util.Random;
import java.util.concurrent.*;

public class ThreadTest3 {
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        //创建一个线程池。里面天生有3个“空”线程。Executors是调度器，对线程池进行管理
        ExecutorService executorService= Executors.newFixedThreadPool(3);
        Runner3 c=new Runner3();//实例化callable对象
        c.setName("莎士比亚");
        Runner3 a=new Runner3();
        a.setName("蔡某");
        Runner3 b=new Runner3();
        b.setName("路飞");
        //将这个对象扔到线程池中，线程池自动分配一个线程来运行liuxiang这个对象的call方法
        //Future用于接受线程内部call方法的返回值
        Future<Integer> result1=executorService.submit(a);
        Future<Integer> result2=executorService.submit(b);
        Future<Integer> result3=executorService.submit(c);

        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        executorService.shutdown();//关闭线程池释放所有资源
        System.out.println("刘翔累计跑了" + result1.get() + "米" );
        System.out.println("老齐累计跑了" + result2.get() + "米" );
        System.out.println("路飞累计跑了" + result3.get() + "米" );
    }


}
class Runner3 implements Callable {
    private String name;
    public void setName(String name) {
        this.name = name;
    }
    //实现Callable接口可以允许我们的线程返回值或抛出异常
    @Override
    public Object call() throws Exception {
        Integer speed=new Random().nextInt(100);
        Integer distince=0;//总共奔跑的距离
        for (int i = 0; i <100 ; i++) {
            Thread.sleep(10);
            distince=distince+i*speed;
            System.out.println(this.name + "已前进" + distince + "米(" + speed + "米/秒)");
        }
        return distince;
    }
}

创建线程的三种方式对比

image.png

并发工具包-Concurrent
JDK1.5以后为我们专门提供了一个并发工具包java.util.concurrent。u java.util.concurrent 包含许多线程安全、测试良好、高性能的并发构建块。创建 concurrent 的目的就是要实现 Collection 框架对数据结构所执行的并发操作。通过提供一组可靠的、高性能并发构建块，开发人员可以提高并发类的线程安全、可伸缩性、性能、可读性和可靠性，