多线程01 --几种创建多线程的方式及比较

多线程

一、创建多线程的几种方式

1. 继承Thread类
2. 实现runable接口
3. 实现callable接口

注意：当创建一个线程后，调用的是start方法，会优先走主线程main；当调用的是run方法时，优先走run方法。线程的执行是CPU调度安排，故可能每次执行都不一样。

使用comments-io jar包进行网图图下载：

public class TestThread02 extends Thread {//通过继承Thread类
    private  String  url;//文件路径
    private String name;//文件名

    public TestThread02(String url, String name) {
        this.url = url;
        this.name = name;
    }
    @Override
    public void run() {
        WebDownloader webDownloader = new WebDownloader();
        webDownloader.downloader(url,name);
        System.out.println("成功下载了文件：" + name);
    }

    public static void main(String[] args) {
        TestThread02 thread01 = new TestThread02("http://b397.photo.store.qq.com/psb?/V12hC8Q41MsPgM/yUU7bLy1MWF*LcU*1VAkDFBvDfj2p4xK3ZktIrbQxCQ!/b/dI0BAAAAAAAA&bo=gAJyBAAAAAAFF8A!&rf=viewer_4", "1.png");
        TestThread02 thread02 = new TestThread02("http://b267.photo.store.qq.com/psb?/V12hC8Q41MsPgM/KLVrmeTeNTAexPoucX6asEYVUTDlPbkGuXn3.MkdguQ!/b/dAsBAAAAAAAA&bo=gAJyBAAAAAAFF8A!&rf=viewer_4", "2.png");
        TestThread02 thread03 = new TestThread02("http://b369.photo.store.qq.com/psb?/V12hC8Q41MsPgM/sWqqYGo32OLLNBZxB5595IRZpArbTRVod*KPEQ5pCNs!/b/dHEBAAAAAAAA&bo=gAJyBAAAAAAFF8A!&rf=viewer_4", "3.png");

        thread01.start();
        thread02.start();
        thread03.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();
            System.out.println("IO异常，download方法出现问题");
        }
    }
}

public class TestCallable implements Callable<Boolean> { //通过实现Callable
    private  String  url;//文件路径						好处：1.可以定义返回值
    private String name;//文件名							  2.可以抛出异常

    public TestCallable(String url, String name) {
        this.url = url;
        this.name = name;
    }
    @Override
    public Boolean call() {
        WebDownloader webDownloader = new WebDownloader();
        webDownloader.downloader(url,name);
        System.out.println("成功下载了文件：" + name);
        return true;
    }

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        TestCallable t1 = new TestCallable("http://b397.photo.store.qq.com/psb?/V12hC8Q41MsPgM/yUU7bLy1MWF*LcU*1VAkDFBvDfj2p4xK3ZktIrbQxCQ!/b/dI0BAAAAAAAA&bo=gAJyBAAAAAAFF8A!&rf=viewer_4", "1.png");
        TestCallable t2 = new TestCallable("http://b267.photo.store.qq.com/psb?/V12hC8Q41MsPgM/KLVrmeTeNTAexPoucX6asEYVUTDlPbkGuXn3.MkdguQ!/b/dAsBAAAAAAAA&bo=gAJyBAAAAAAFF8A!&rf=viewer_4", "2.png");
        TestCallable t3 = new TestCallable("http://b369.photo.store.qq.com/psb?/V12hC8Q41MsPgM/sWqqYGo32OLLNBZxB5595IRZpArbTRVod*KPEQ5pCNs!/b/dHEBAAAAAAAA&bo=gAJyBAAAAAAFF8A!&rf=viewer_4", "3.png");

        //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();
        //关闭服务
        ser.shutdownNow();
    }
}
//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();
            System.out.println("IO异常，download方法出现问题");
        }
    }
}

继承Thread类和实现Runnable接口开启线程对比：

public class TestThread01 extends Thread{
    @Override
    public void run() {
        //run方法线程体
        for (int i = 0; i < 20; i++) {
            System.out.println("我在玩压缩---------"+i);
        }
    }
    //创建main方法 ，主线程
    public static void main(String[] args) {
        //创建一个线程对象
        TestThread01 thread01 = new TestThread01();
        //调用start方法开启线程
        thread01.start();
        for (int i = 0; i < 20; i++) {
            System.out.println("我在学习---------"+i);
        }
    }
}

public class TestThread03 implements Runnable{
    @Override
    public void run() {
        //run方法线程体
        for (int i = 0; i < 20; i++) {
            System.out.println("我在玩压缩---------"+i);
        }
    }
    //创建main方法 ，主线程
    public static void main(String[] args) {
        //创建Runnable接口的实现类对象
        TestThread03 testThread03 = new TestThread03();
        //创建线程对象，通过线程对象开启我们的线程，代理模式
       /* Thread thread = new Thread(testThread03);
        thread.start();*/
        new Thread(testThread03).start();
        for (int i = 0; i < 20; i++) {
            System.out.println("我在学习---------"+i);
        }
    }
}