线程创建方式3-实现 callable接口（Java）

Myth丶恋晨 2023-10-04 15:54 43阅读 0赞

### 线程创建方式3-实现 callable接口（Java） ###

*  线程创建方式三：实现 callable接口  
    callable的好处：  
    1.可以定返回值  
    2.可以抛出异常

package src.Demo02;
    
    import java.io.File;
    import java.io.IOException;
    import java.net.URL;
    import java.util.concurrent.Callable;
    import java.util.concurrent.ExecutorService;
    import java.util.concurrent.Executors;
    import java.util.concurrent.Future;
    
    public class TestCallable implements Callable<Boolean> {
        
        private String url;  //网络图片地址
        private String name; //保存的文件名
    
        //构造器--实现调用
        public TestCallable(String url, String name) {
        
            this.url = url;
            this.name = name;
    
        }
    
        //下载图片的执行体
        @Override
        public Boolean call() {
        
            WebDownloader webDownloader = new WebDownloader();
            //传入方法
            webDownloader.downloader(url, name);
            System.out.println("下载的文件名为" + name);
            return true;
        }
    
        public static void main(String[] args) throws Exception {
        
            TestCallable t1 = new TestCallable("http://b-ssl.duitang.com/uploads/item/201704/21/20170421083329_3cxt8.png", "1.png");
            TestCallable t2 = new TestCallable("https://i02piccdn.sogoucdn.com/7e1dad42a62db2df", "2.png");
            TestCallable t3 = new TestCallable("https://i01piccdn.sogoucdn.com/f13b319fd77655ec", "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，down的方法出现问题！");
            }
        }
    
    }

package src.Demo02;
    
    import java.io.File;
    import java.net.URL;
    
    public class FileUtils {
        
        public static void copyURLToFile(URL url, File file) {
        
        }
    }