实现Callable接口

多线程下载图片

package test2;

import org.apache.commons.io.FileUtils;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.*;

public class TestCallable implements Callable<Boolean>{


        private String url;
        private String filename;

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

    @Override
    public Boolean call() {
        WebDownloader webDownloader=new WebDownloader();
        webDownloader.downloader(url,filename);
        System.out.println("图片下载结束名字为"+filename);
        return true;
    }

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        TestCallable t1=new TestCallable("http://www.whxzn.com/images/banner/shouhou.jpg","1.jpg");
        TestCallable t2=new TestCallable("http://www.whxzn.com/images/faq/1.jpg","2.jpg");
        TestCallable t3=new TestCallable("http://www.whxzn.com/images/faq/3.jpg","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();

        //关闭服务
        ser.shutdownNow();


        }

}
//下载器
class WebDownloader{
    //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();
            System.out.println("io异常");
        }
    }
}