用callable接口和runnable接口实现多线程同步下载图片

//线程创建方式三：实现callable接口
/*
callable的好处
1、可以定义返回值
2、可以抛出异常
 */
public class TestCallable implements Callable<Boolean> {

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

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

    }
    //下载图片线程的执行体
    @Override
    public Boolean call() {
        WebDownloader webDownloader = new WebDownloader();
        webDownloader.downloader(url,name);
        System.out.println("下载的文件名为："+name);
        return true;

    }
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        TestCallable t1 = new TestCallable("https://www.wahaotu.com/uploads/allimg/201904/1555074510295049.jpg\n","1.jpg");
        TestCallable t2 = new TestCallable("https://www.wahaotu.com/uploads/allimg/201904/1555074510295049.jpg\n","2.jpg");
        TestCallable t3 = new TestCallable("https://www.wahaotu.com/uploads/allimg/201904/1555074510295049.jpg\n","3.jpg");

       //创建执行服务：
        ExecutorService ser = Executors.newFixedThreadPool(3);

        //提交执行
        Future<Boolean> r1 = ser.submit(t1);
        Future<Boolean> r2 = ser.submit(t2);
        Future<Boolean> r3 = ser.submit(t3);

        //获取结果
        boolean rs1 = r1.get();
        boolean rs2 = r2.get();
        boolean rs3 = r3.get();

        System.out.println(rs1);
        System.out.println(rs2);
        System.out.println(rs3);

        //关闭服务
        ser.shutdownNow();
    }
}




//下载器
class WebDownloader{
    //下载方法  URL资源定位器
    public void downloader(String url,String name){
        try {
            FileUtils.copyURLToFile(new URL(url),new File(name));
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("IO异常，downloader方法出现问题");
        }

    }
}
==============================================================================

实现runnable接口,实现多线程同步下载图片
public class TestThread2 implements Runnable{

    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;

    }

    //下载图片线程的执行体
    @Override
    public void run() {
        WebDownloader webDownloader = new WebDownloader();
        webDownloader.downloader(url,name);
        System.out.println("下载的文件名为："+name);

    }

    public static void main(String[] args) {
        TestThread2 t1 = new TestThread2("https://www.wahaotu.com/uploads/allimg/201904/1555074510295049.jpg\n","1.jpg");
        TestThread2 t2 = new TestThread2("https://www.wahaotu.com/uploads/allimg/201904/1555074510295049.jpg\n","2.jpg");
        TestThread2 t3 = new TestThread2("https://www.wahaotu.com/uploads/allimg/201904/1555074510295049.jpg\n","3.jpg");

 //调用start()方法并不是按顺序执行，每次执行的顺序不一样，调用的顺序由CPU决定

        new Thread(t1).start();
        new Thread(t2).start();
        new Thread(t3).start();
       
    }
}

//下载器
class WebDownloader{
    //下载方法  URL资源定位器
    public void downloader(String url,String name){
        try {
            FileUtils.copyURLToFile(new URL(url),new File(name));
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("IO异常，downloader方法出现问题");
        }

    }
}