Java多线程的三种实现方式

public class TestThread1 extends Thread {
    //副线程
    public void run(){
        for (int i = 0; i <20 ; i++) {
            System.out.println("我在学习java");
        }
    }

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

        //副线程启动
        TestThread1 testThread1 = new TestThread1();
        testThread1.start();


        for (int i = 0; i <20 ; i++) {
            System.out.println("我在吃饭");
        }
    }
}

public class TestThread3 implements Runnable {
    //副线程
    public void run(){
        for (int i = 0; i <20 ; i++) {
            System.out.println("我在学习java");
        }
    }

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

        //创建runnable接口的实现类对象
        TestThread3 testThread3 = new TestThread3();
        //创建线程对象，通过线程对象来开启线程,代理
        //Thread thread = new Thread(testThread3);
        //thread.start();
        new Thread(testThread3).start();


        for (int i = 0; i <100 ; i++) {
            System.out.println("我在吃饭");
        }
    }
}

//线程创建方式三：实现callable接口
//优点：可以定义返回值类型，可以抛出异常
public class TestCallable implements Callable {
    private  String url;//网络图片地址
    private  String filename;//保存的文件名

    public TestCallable(String url,String filename){
        this.url = url;
        this.filename = filename;
    }

    //下载图片线程的执行体
    public Boolean call() {
        WebDownLoad webDownLoad = new WebDownLoad();
        webDownLoad.downloader(url,filename);
        System.out.println("下载了文件名为："+filename);
        return true;

    }


    public static void main(String[] args) throws ExecutionException, InterruptedException {
        TestCallable t1 = new TestCallable("https://pics2.baidu.com/feed/32fa828ba61ea8d34c7cb6cb530c7644241f58b0.png?token=ae95ec0bbcf9d978e434c0ff1ae984ea","a1.jpg");
        TestCallable t2 = new TestCallable("https://pics5.baidu.com/feed/314e251f95cad1c8512f7444bf382103c83d51ca.jpeg?token=2285fba0b9ca8603690be82ae1b95bba","a2.jpg");
        TestCallable t3 = new TestCallable("https://pics5.baidu.com/feed/91529822720e0cf36459feecc840b415be09aa08.jpeg?token=7b41f4d8465de0909a6eb82180ced050","a3.jpg");

       //创建执行服务
        ExecutorService executorService = Executors.newFixedThreadPool(3);
        //提交执行,相当于start()
        Future r1 = executorService.submit(t1);
        Future r2 = executorService.submit(t2);
        Future r3 = executorService.submit(t3);

        //获取结果
        Boolean rs1 = r1.get();
        Boolean rs2 = r2.get();
        Boolean rs3 = r3.get();
        System.out.println(rs1.toString()+rs2+rs3);

        //关闭服务
        executorService.shutdownNow();



    }


}

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