实现多线程方式1:继承类Thread——重写方法run——调用方法start
从网络下载图片首先要增加包commons-io.jar
import org.apache.commons.io.FileUtils; import java.io.File; import java.io.IOException; import java.net.URL; /** * 下载图片 */ public class WebDownLoader { /** * 下载工具 * @param url * @param name */ public void download(String url,String name){ try { FileUtils.copyURLToFile(new URL(url),new File(name)); } catch (IOException e) { e.printStackTrace(); } } }
public class TDownloader extends Thread{ String url; String name; public TDownloader(String url, String name) { this.url = url; this.name = name; } @Override public void run() { WebDownLoader webDownLoader=new WebDownLoader(); webDownLoader.download(url,name); } public static void main(String[] args) { TDownloader t1=new TDownloader("http://pic28.nipic.com/20130424/3822951_142421949000_2.jpg","photo1.jpg"); TDownloader t2=new TDownloader("http://pic1.win4000.com/wallpaper/2018-01-23/5a669e431688c.jpg","photo2.jpg"); TDownloader t3=new TDownloader("http://pic1.win4000.com/wallpaper/6/57a2ea76bcc06.jpg","photo3.jpg"); t1.start(); t2.start(); t3.start(); } }
实现多线程方式2:实现Runnable——重写run()方法——new Thread( 实现了Runnable接口的对象 ).start
下载工具类和上面一样,实现多线程的类变了
public class TDownloader implements Runnable{ String url; String name; public TDownloader(String url, String name) { this.url = url; this.name = name; } @Override public void run() { WebDownLoader webDownLoader=new WebDownLoader(); webDownLoader.download(url,name); } public static void main(String[] args) { TDownloader t1=new TDownloader("http://pic28.nipic.com/20130424/3822951_142421949000_2.jpg","photo1.jpg"); TDownloader t2=new TDownloader("http://pic1.win4000.com/wallpaper/2018-01-23/5a669e431688c.jpg","photo2.jpg"); TDownloader t3=new TDownloader("http://pic1.win4000.com/wallpaper/6/57a2ea76bcc06.jpg","photo3.jpg"); new Thread(t1).start(); new Thread(t2).start(); new Thread(t3).start(); } }