Executors.newFixedThreadPool()与CompletableFuture两种方式获取异步计算结果代码示例

不念不忘少年蓝@ 2023-10-08 10:23 10阅读 0赞

package com.zhangxueliang.demo.springbootdemo.JUC.c_026_01_ThreadPool;
    
    import java.util.ArrayList;
    import java.util.List;
    import java.util.concurrent.*;
    
    /**
     * @ProjectName springbootdemo_src
     * @ClassName T09_FixedThreadPool
     * @Desicription TODO
     * @Author Zhang Xueliang
     * @Date 2019/12/5 19:55
     * @Version 1.0
     **/
    public class T09_FixedThreadPool {
    
        public static void main(String[] args) throws ExecutionException, InterruptedException {
            long start,end;
            start=System.currentTimeMillis();
            //第一种方式
            // List<Integer> integers = getPrime(1, 200000);//一共耗时: 2156
            
            //第二种方式
            ExecutorService executorService = Executors.newFixedThreadPool(4);//一共耗时: 1104
            Task task1 = new Task(1, 50000);
            Task task2 = new Task(50001, 100000);
            Task task3 = new Task(100001, 150000);
            Task task4 = new Task(150001, 200000);
            /*Future<List<Integer>> future1 = executorService.submit(task1);
            Future<List<Integer>> future2 = executorService.submit(task2);
            Future<List<Integer>> future3 = executorService.submit(task3);
            Future<List<Integer>> future4 = executorService.submit(task4);
            List<Integer> list1 = future1.get();
            List<Integer> list2 = future2.get();
            List<Integer> list3 = future3.get();
            List<Integer> list4 = future4.get();*/
            
            //第三种方式
            CompletableFuture<List<Integer>> c1 = CompletableFuture.supplyAsync(() -> getPrime(1, 50000));//一共耗时: 1269
            CompletableFuture<List<Integer>> c2 = CompletableFuture.supplyAsync(() -> getPrime(50001, 100000));
            CompletableFuture<List<Integer>> c3 = CompletableFuture.supplyAsync(() -> getPrime(100001, 150000));
            CompletableFuture<List<Integer>> c4 = CompletableFuture.supplyAsync(() -> getPrime(150001, 200000));
            List<Integer> list1 = c1.get();
            List<Integer> list2 = c2.get();
            List<Integer> list3 = c3.get();
            List<Integer> list4 = c4.get();
            end=System.currentTimeMillis();
            System.out.printf("一共耗时: %s",end-start);
            executorService.shutdown();
        }
    
        static class Task implements Callable<List<Integer>> {
            int start,end;
    
            public Task(int start, int end) {
                this.start = start;
                this.end = end;
            }
    
            @Override
            public List<Integer> call() throws Exception {
                return getPrime(start,end);
            }
        }
    
        private static List<Integer> getPrime(int start, int end) {
            List<Integer> results = new ArrayList<>();
            for (int j = start; j <end ; j++) {
                if (isPrime(j)) results.add(j);
            }
            return results;
        }
    
        private static boolean isPrime(int num) {
            for (int i = 2; i <num/2 ; i++) {
                if (num%i==0) return false;
            }
            return true;
        }
    }