,Java线程Callable_Future_Executors线程池的使用

1.首先创建任务,继承callable接口能返回结果。

package com.currentPro.task;

import java.util.concurrent.Callable;

public class MuniusTask implements Callable<Integer>{

    private Integer number;
    
    public MuniusTask (Integer number){
        this.number = number;
    }
    
    
    @Override
    public Integer call() throws Exception {
        int result ;
        result = number - 1;
        return result;
    }

}

2.创建TaskExecutor，用来创建线程池

public class MuniusTaskExecutor {

    protected ExecutorService executors;
    
    public MuniusTaskExecutor(Integer threadNums){
        this.executors = Executors.newFixedThreadPool(threadNums);
    }
}

3.测试

package com.currentPro.task;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

public class TaskTest {

    public static void main(String[] args) throws InterruptedException, ExecutionException {
        //创建线程池
        MuniusTaskExecutor  muniusTaskExecutor  = new MuniusTaskExecutor (10);

        //结果
        List<Future<Integer>> resultList = new ArrayList<Future<Integer>> ();

        Random random = new Random();

        for (int i = 0; i < 4; i++) {
            Integer number = random.nextInt(10);
            System.out.println("random值：" + number);
            //创建任务
            MuniusTask m1 = new MuniusTask(number);
            //提交任务
            Future<Integer> result = muniusTaskExecutor.executors.submit(m1);

            resultList.add(result);
        }

        for (Future<Integer> future : resultList) {
            System.out.println("Future result is - " + " - " + future.get() + "; And Task done is " + future.isDone());
        }
        muniusTaskExecutor.executors.shutdown();
    }

}

 

4.结果

random值：2
random值：0
random值：2
random值：8
Future result is -  - 1; And Task done is true
Future result is -  - -1; And Task done is true
Future result is -  - 1; And Task done is true
Future result is -  - 7; And Task done is true

 

如果要一次提交多个任务的话，使用completionservice

package com.eminem.test;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class CompletionServiceDemo {

    public static void main(String[] args) {
        // 创建线程池
        Executor executor = Executors.newFixedThreadPool(10);
        // 把线程池给予cs,能一次开启多个callable任务
        CompletionService cs = new ExecutorCompletionService(executor);

        for (int i = 1; i <= 10; i++) {
            final int seq = i;
            Future future = cs.submit(new Callable<Integer>() {

                @Override
                public Integer call() throws Exception {
                    int random = new Random().nextInt(5000);
                    System.out.println("seq" + seq + "休眠了:" + random + "秒");
                    Thread.sleep(random);
                    return seq;
                }

            });
        }

        try {
            // 依次获取cs的执行任务完后的结果
            for (int i = 0; i <= 10; i++) {
                System.out.println(cs.take().get());
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
    }
}

结果：

seq1休眠了:2002秒
seq3休眠了:603秒
seq5休眠了:1955秒
seq7休眠了:802秒
seq2休眠了:1809秒
seq6休眠了:2247秒
seq4休眠了:2667秒
seq8休眠了:2807秒
seq9休眠了:4604秒
seq10休眠了:503秒
10
3
7
2
5
1
6
4
8
9