java的FutureTask代码例子讲解

电玩女神 2023-06-27 05:38 23阅读 0赞

## FutureTask： ##

**FutureTask其实相当于是对Callable和Runnable的整合  
在实际开发过程中，将那些耗时较长，且可以并行的操作都封装成一个FutureTask。**

package com.zr.concurrency.test.others;
    
    import lombok.extern.slf4j.Slf4j;
    
    import java.util.concurrent.*;
    
    /** * @description: JUC中FutureTask的使用 * FutureTask： * FutureTask其实相当于是对Callable和Runnable的整合 * 在实际开发过程中，将那些耗时较长，且可以并行的操作都封装成一个FutureTask。 * @author: liangrui * @create: 2020-01-03 16:18 **/
    @Slf4j
    public class FutureTaskExample { 
    
        public static void main(String[] args) throws InterruptedException, ExecutionException { 
            //创建FutureTask类
            //使用Callable,既可以抛异常，又有返回值
            FutureTask<String> futureTask1=new FutureTask<>(new Callable<String>() { 
                @Override
                public String call() throws Exception { 
                    //callable执行任务
                    log.info("do something in callable");
                    Thread.sleep(5000);
                    //执行成功返回"Done"
                    return "Done";
                }
            });
    
            //创建FutureTask类
            //使用Runnable，返回值需要写为第二个参数result,不能抛异常
            FutureTask<String> futureTask2=new FutureTask<>(new Runnable(){ 
                @Override
                public void run() { 
                    //runnable执行任务
                    log.info("do something in runnable");
                    try { 
                        Thread.sleep(5000);
                    } catch (InterruptedException e) { 
                        e.printStackTrace();
                    }
                }
            },"Done");//执行成功返回result:"Done"
    
            //创建线程池
            ExecutorService executorService=Executors.newCachedThreadPool();
            executorService.submit(futureTask1);
            executorService.submit(futureTask2);
            //关闭线程池，释放资源
            executorService.shutdown();
            
            //main线程执行任务时间
            Thread.sleep(1000);
            log.info("main finished,waiting...............");
            //获取各线程执行成功的返回值
            String result1=futureTask1.get();
            String result2=futureTask2.get();
            //输出
            log.info("result1:{}",result1);
            log.info("result2:{}",result2);
        }
    }

## 运行结果： ##

16:41:29.778 [Thread-0] INFO com.zr.concurrency.test.others.FutureTaskExample - do something in callable
    16:41:29.778 [Thread-1] INFO com.zr.concurrency.test.others.FutureTaskExample - do something in runnable
    16:41:30.775 [main] INFO com.zr.concurrency.test.others.FutureTaskExample - main finished,waiting...............
    16:41:34.784 [main] INFO com.zr.concurrency.test.others.FutureTaskExample - result1:Done
    16:41:34.788 [main] INFO com.zr.concurrency.test.others.FutureTaskExample - result2:Done