Java多线程

package thread;

public class TestThread extends Thread{
    @Override
    public void run() {
        super.run();
        for (int i=0;i<20;i++){
            System.out.println("run方法"+i);
        }
    }

    public static void main(String[] args) {
        //main线程，主线程

        //创建一个线程对象，调用start方法开启线程
        TestThread testThread = new TestThread();
        testThread.start();

        for (int i = 0; i < 200; i++) {
            System.out.println("主线程"+i);
        }
    }
}

package thread;


import org.apache.commons.io.FileUtils;

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

//联系Thread，实现多线程同步下载
public class TestThread2 extends Thread{

    private String url; //网络图片地址
    private String name; //保存的文件名


    public TestThread2(String url,String name){
            this.url = url;
            this.name = name;
    }

    //下载图片的线程执行体
    @Override
    public void run() {
        WebDownloader webDownloader = new WebDownloader();
        webDownloader.downloader(url,name);
        System.out.println("下载了文件名为："+name);
    }

    public static void main(String[] args) {
        TestThread2 testThread1 = new TestThread2("https://cdn.jsdelivr.net/gh/zhangliyuangit/img/%E8%85%BE%E8%AE%AF%E4%BA%911.png","D:/a_test/1.jpg");
        TestThread2 testThread2 = new TestThread2("https://cdn.jsdelivr.net/gh/zhangliyuangit/img/%E8%85%BE%E8%AE%AF%E4%BA%912.png","D:/a_test/2.jpg");
        TestThread2 testThread3 = new TestThread2("https://cdn.jsdelivr.net/gh/zhangliyuangit/img/%E8%85%BE%E8%AE%AF%E4%BA%913.png","D:/a_test/3.jpg");

        testThread1.start();
        testThread2.start();
        testThread3.start();
    }
}

//下载器
class WebDownloader{
    //下载方法
    public void downloader(String url,String name){
        try {
            FileUtils.copyURLToFile(new URL(url),new File(name));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

package thread;

public class TestThread3 implements Runnable{
    @Override
    public void run() {
        for (int i = 0; i < 20; i++) {
            System.out.println("run方法"+i);
        }
    }

    public static void main(String[] args) {
        //创建runnable接口的实现类
        TestThread3 testThread3 = new TestThread3();
        //创建线程对象，通过线程对象开启线程，代理
        Thread thread = new Thread(testThread3);
        thread.start();

        //new Thread(new TestThread3()).start();

        for (int i = 0; i < 200; i++) {
            System.out.println("主线程"+i);
        }
    }
}

package thread;

/**
 * 多个线程操作一个对象
 * 买火车票
 */
public class TestThread4 implements Runnable{
    //票数
    private int ticketNums = 10;

    @Override
    public void run() {
        while (true){
            if (ticketNums<=0){
                break;
            }
            //模拟延迟
            try {
                Thread.sleep(200);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName()+"---->拿到了第"+ticketNums--+"张票");
        }
    }

    public static void main(String[] args) {
        TestThread4 t4 = new TestThread4();
        new Thread(t4,"小明").start();
        new Thread(t4,"老师").start();
        new Thread(t4,"黄牛").start();
    }
}

package thread;

/**
 * 测试stop
 * 建议线程正常停止-->利用次数，不建议死循环
 * 建议使用标志位-->设置一个标志位
 * 不用使用stop或者destory等过时或者JDK不建议使用的方法
 */
public class TestThread5 implements Runnable{

    //设置一个标志位
    private boolean flag = true;

    @Override
    public void run() {
        int i = 0;
        while (flag){
            System.out.println("run....Thread"+i++);
        }
    }

    //设置一个公开的方法停止线程，转换标志位
    public void stop(){
        this.flag = false;
    }

    public static void main(String[] args) {
        TestThread5 thread5 = new TestThread5();
        new Thread(thread5).start();

        for (int i = 0; i < 1000; i++) {
            System.out.println("main"+i);
            if (i == 900){
                //调用stop方法切换标志位，让线程停止
                thread5.stop();
                System.out.println("线程该停止了");
            }
        }
    }
}

package thread;

public class TestYield {
    public static void main(String[] args) {
        MyYield myYield = new MyYield();

        new Thread(myYield,"a").start();
        new Thread(myYield,"b").start();

    }
}

class MyYield implements Runnable{
    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName()+"线程开始执行");
        Thread.yield();//礼让
        System.out.println(Thread.currentThread().getName()+"线程停止执行");
    }
}

package thread;

import java.util.concurrent.locks.ReentrantLock;

/**
 * @author zhang
 * @date 2020/5/31 10:24
 */
public class TestLock {
    public static void main(String[] args) {
        BuyTicket buyTicket = new BuyTicket();

        new Thread(buyTicket,"小明").start();
        new Thread(buyTicket,"小红").start();
        new Thread(buyTicket,"黄牛").start();
    }
}

class BuyTicket implements Runnable{
    int ticketNum = 10;

    //定义Lock锁
    private final ReentrantLock lock = new ReentrantLock();

    @Override
    public void run() {
        while (true){
            try {
                lock.lock();//加锁
                if (ticketNum>0){
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName()+"买到了"+ticketNum--);
                }else {
                    break;
                }
            }finally {
                //解锁
                lock.unlock();
            }
        }
    }
}

package thread;

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

/**
 * @author zhang
 * @date 2020/5/31 14:58
 * 测试线程池
 */
public class TestPool {
    public static void main(String[] args) {
        //创建线程池
        ExecutorService service = Executors.newFixedThreadPool(10);

        //执行
        service.execute(new MyThread());
        service.execute(new MyThread());
        service.execute(new MyThread());
        service.execute(new MyThread());

        //关闭连接
        service.shutdown();
    }
}
class MyThread implements Runnable{
    @Override
    public void run() {
        for (int i = 0; i < 10; i++) {
            System.out.println(Thread.currentThread().getName()+i);
        }
    }
}