多线程1

多线程1

一个进程可以有多个线程

process、thread

main（）主线程还可以运行其他线程

线程创建

继承Thread类、实现Runnable（接口）、实现Callable（接口）

继承Thread，重写（）run方法

线程开启不一定立即执行，由CPU调用执行

package thread;
//创建线程方式一：继承Thread类，重写run（）方法，调用start开启线程
public class Demo1 extends Thread{
    @Override
    //run方法线程体
    public void run() {
        for (int i = 0; i < 1001; i++) {
            System.out.println("执行" + i);
        }
    }
//main方法主线程
    public static void main(String[] args) {
        //创建线程对象，
        Demo1 demo1 = new Demo1();
        //调用run方法是先执行run方法再执行下面的循环，
        // 而调用start方法是两个线程同时执行，系统调用的时间片有先后而已
        demo1.run();
        for (int i = 0; i < 1001; i++) {
            System.out.println("hello world!" + i);
        }
    }
}

多线程文件下载

package thread;

import org.apache.commons.io.FileUtils;

import java.io.File;
import java.io.IOException;
import java.net.URL;

public class WebFileDownLoader {//网页文件下载器
    public void downFile(String name,String url){
        File file = new File(name);
        try {
            FileUtils.copyURLToFile(new URL(url),file);//使用别人封装好的1类实现
        } catch (IOException e) {//捕获异常，判断是有在此处出现错误
            System.out.println(e + "WebFileDownLoader类downFile方法");
        }
    }
}

package thread;

public class Demo2 extends Thread{//使用线程实现多图片同时下载
    private String name;
    private String url;
    public Demo2(){ }

    public Demo2(String name, String url) {
        this.name = name;//文件名
        this.url = url;//url名
    }

    @Override
    public void run() {
        WebFileDownLoader webFileDownLoader = new WebFileDownLoader();
        webFileDownLoader.downFile(name,url);
        System.out.println(name);
    }
/*
* D:\ideaProject\Test\javaSE\jichuyufa\resources\3.jpg
D:\ideaProject\Test\javaSE\jichuyufa\resources\2.jpg
D:\ideaProject\Test\javaSE\jichuyufa\resources\4.jpg
* 线程同时进行
* */
    public static void main(String[] args) {
        Demo2 demo2 = new Demo2("D:\\ideaProject\\Test\\javaSE\\jichuyufa\\resources\\2.jpg" ,
                "https://tse4-mm.cn.bing.net/th/id/OIP-C.owpbNjuu23xkyc4yrX9BDQHaEo?pid=ImgDet&rs=1");
        Demo2 demo3 = new Demo2("D:\\ideaProject\\Test\\javaSE\\jichuyufa\\resources\\3.jpg" ,
                "https://desk-fd.zol-img.com.cn/t_s960x600c5/g1/M0B/03/06/ChMljl402K6IOTZbAARWayFg6S4AAQJPwFhuRIABFaD752.jpg");
        Demo2 demo4 = new Demo2("D:\\ideaProject\\Test\\javaSE\\jichuyufa\\resources\\4.jpg" ,
                "https://pic.3gbizhi.com/2019/0928/20190928012439343.jpg");
        demo2.start();
        demo3.start();
        demo4.start();

        new WebFileDownLoader().downFile("D:\\ideaProject\\Test\\javaSE\\jichuyufa\\resources\\5.jpg",
                "https://ts1.cn.mm.bing.net/th/id/R-C.987f582c510be58755c4933cda68d525?r" +
                        "ik=C0D21hJDYvXosw&riu=http%3a%2f%2fimg.pconline.com.cn%2fimages%2fupload%2fupc%2ftx%2fwallpaper%2f1305%" +
                        "2f16%2fc4%2f20990657_1368686545122.jpg&ehk=netN2qzcCVS4ALUQfDOwxAwFcy41oxC%2b0xTFvOYy5ds%3d&risl=&pid=ImgRaw&r=0");
    }
}

实现runnable接口

定义一个类实现Runnable接口

实现run方法，编写线程体

创建线程对象，调用start方法启动线程，推荐使用，因为java单继承

package thread;
//创建线程方式二：实现Runnable接口，重写run（）方法，执行线程需要1丢入runnable接口的实现类中，调用start开启线程
public class TestThread1 implements Runnable{
    @Override
    public void run() {
        for (int i = 0; i < 100; i++) {
            System.out.println("执行Runnable" + i);
        }
    }

    public static void main(String[] args) {
        TestThread1 testThread1 = new TestThread1();
        Thread thread = new Thread(testThread1);
        thread.start();
    }
}

线程并发问题

package thread;
//线程并发，操作同一对象会出现紊乱
public class Demo3 implements Runnable{
    public int ticketNum = 20;
    @Override
    public void run() {
        while (true) {
            try {
                Thread.sleep(100);
                if (ticketNum == 0) {
                    break;
                }else
                    System.out.println(Thread.currentThread().getName() + "拿到了第" + ticketNum-- + "张票");
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        Demo3 demo3 = new Demo3();//打印结果出现了紊乱
        new Thread(demo3,"A").start();
        new Thread(demo3,"B").start();
        new Thread(demo3,"C").start();
    }
}

龟兔赛跑3

package thread;
//龟兔赛跑
public class Demo4 implements Runnable{
    private static String winner;
    public boolean gameOver(int steps){
        if (winner!= null){
            return true;
        }else {
            if (steps >= 9999){
                winner = Thread.currentThread().getName();
                System.out.println(winner);
                return true;
            }
        }
        return false;
    }
    @Override
    public void run() {
        for (int i = 0; i < 10000; i++) {
            if (Thread.currentThread().getName().equals("兔子")){
                i+=999;
                try {
                    System.out.println(Thread.currentThread().getName() + "============跑了" + i + "步");
                    Thread.sleep(10);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            boolean flag = gameOver(i);
            if (flag){
                break;
            }else if(Thread.currentThread().getName().equals("乌龟"))
                System.out.println(Thread.currentThread().getName() + "跑了" + i + "步");
        }
    }

    public static void main(String[] args) {
        Demo4 demo4 = new Demo4();
        new Thread(demo4,"兔子").start();
        new Thread(demo4,"乌龟").start();
    }
}

Callable

package thread;

import java.util.concurrent.*;

public class CallAble implements Callable<Boolean> {
    private String name;
    private String url;
    public CallAble(){ }

    public CallAble(String name, String url) {
        this.name = name;//文件名
        this.url = url;//url名
    }
    @Override
    public Boolean call() throws Exception {
        WebFileDownLoader webFileDownLoader = new WebFileDownLoader();
        webFileDownLoader.downFile(this.name,this.url);
        System.out.println(this.name);
        return true;
    }

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        CallAble demo2 = new CallAble("D:\\ideaProject\\Test\\javaSE\\jichuyufa\\resources\\2.jpg" ,
                "https://tse4-mm.cn.bing.net/th/id/OIP-C.owpbNjuu23xkyc4yrX9BDQHaEo?pid=ImgDet&rs=1");
        CallAble demo3 = new CallAble("D:\\ideaProject\\Test\\javaSE\\jichuyufa\\resources\\3.jpg" ,
                "https://desk-fd.zol-img.com.cn/t_s960x600c5/g1/M0B/03/06/ChMljl402K6IOTZbAARWayFg6S4AAQJPwFhuRIABFaD752.jpg");
        CallAble demo4 = new CallAble("D:\\ideaProject\\Test\\javaSE\\jichuyufa\\resources\\4.jpg" ,
                "https://pic.3gbizhi.com/2019/0928/20190928012439343.jpg");
        //创建执行服务，创建新的线程池
        ExecutorService threadPool = Executors.newFixedThreadPool(3);
        //提交执行
        Future<Boolean> submit1 = threadPool.submit(demo2);
        Future<Boolean> submit2 = threadPool.submit(demo3);
        Future<Boolean> submit3 = threadPool.submit(demo4);
        //获取结果
        System.out.println(Thread.currentThread().getName() + submit1.get());
        System.out.println(Thread.currentThread().getName() + submit2.get());
        System.out.println(Thread.currentThread().getName() + submit3.get());
        //关闭服务
        threadPool.shutdown();

    }
}

静态代理模式

package thread;
/*静态代理模式：
真实对象和代理对象都要实现同一个接口
代理对象要代理真实角色
*代理对象可以做很多真实对象做不了的事
真实对象只需要做自己的事即可
* */
public class StaticProxy {
    public static void main(String[] args) {
        //new Restaurant(new Person("sang")).eatHappy();
        Person sang = new Person("sang");//这个人,要吃饭
        Restaurant restaurant = new Restaurant(sang);//去饭店吃饭
        new Thread(() -> System.out.println("我饿了！")).start();//线程也是静态代理
        restaurant.eatHappy();//饭店提供服务，你只管安心吃饭

    }
}
interface eatFood{
    void eatHappy();
}
//代理角色，帮助你提供能吃的食物
class Restaurant implements eatFood{
    private Person target;

    public Restaurant(Person person) {
        this.target = person;
    }
    @Override
    public void eatHappy() {
        before();
        this.target.eatHappy();
        after();
    }

    private void after() {
        System.out.println("收钱，找零");
    }

    private void before() {
        System.out.println("厨师做饭，提供用餐环境");
    }
}
//真实角色，去吃饭
class Person implements eatFood{
    public String name;

    public Person(String name) {
        this.name = name;
    }

    @Override
    public void eatHappy() {
        System.out.println(this.name + " happy eat food!");
    }
}

Lamda表达式

避免内部类定义过多

实质属于函数式编程的概念

（params）-> expression[表达式]

（params）-> statement[语句]

（params）-> {statements}

package thread;

public class LambdaTest implements Test{
    public static void main(String[] args) {
        //Lambda表达式
        Test like = ()-> {
            System.out.println("test5");
        };
        like.test();
        //4.静态内部类
//        Test1 test1 = new Test1();
//        test1.test();
        //1.实现类new LambdaTest().test();
        //2.匿名内部类
        /*new Test() {
            @Override
            public void test() {
                System.out.println("test2");
            }
        }.test();*/
        //3.局部内部类
        /*class Like implements Test{
            @Override
            public void test() {
                System.out.println("test3");
            }
        }
        new Like().test();*/
    }
    //4.静态内部类
    static class Test1 implements Test{
        @Override
        public void test() {
            System.out.println("test4");
        }
    }
    @Override
    public void test() {
        System.out.println("test1");
    }
}
interface Test{
    void test();
} 

package thread;

import java.util.Scanner;

public class LambdaDemo1 {
    //静态内部类
    static class Lovely1 implements Test1{
        @Override
        public int add(int a, int b) {
            int c = a + b;
            System.out.println(c);
            return c;
        }
    }
    public static void main(String[] args) {
        //匿名内部类
        Test1 test1 = (int a,int b) ->{
            int c = a + b;
            System.out.println(c);
            return 0;
        };
        test1.add(2,4);
        //简化参数类型
        test1 = (a,b) -> {
            System.out.println( a+ b);
            return a + b;
        };
        int c = test1.add(5,7);
        System.out.println(c);

        //new Lovely1().add(2,3);
//        Lovely lovely = new Lovely();
//        lovely.add(1,2);
    }
}
//Lambda表达式前提是接口必须是函数式接口，只有一个方法的接口
interface Test1{
    int add(int a,int b);
}
//外部类
class Lovely implements Test1{

    @Override
    public int add(int a, int b) {
        int c = a + b;
        System.out.println(c);
        return c;
    }
}