ForkJoin ForkJoinForkJoin图片来源：狂神说JavaForkJoin 任务窃取这个任务中维护的都是双端队列B的任务执行完了，去帮助A执行图片来源：狂神说Javapackage com.sw.forkjoin; import java.util.concurrent.RecursiveTask; /** * @Author suaxi * @Date 2021/2/16 17:24 * 1、通过forkjoinPool来执行 * 2、计算任务forkjoinPool.execute(ForkJoinTask task) * 3、计算类要继承 ForkJoinTask */ public class ForkJoinTest extends RecursiveTask<Long> { private Long start; private Long end; //临界值 private Long temp = 1000L; public ForkJoinTest(Long start, Long end) { this.start = start; this.end = end; } //计算任务 @Override protected Long compute() { if ((end-start)<temp){ Long sum = 0L; for (Long i = start; i <= end; i++) { sum += i; } return sum; }else { //forkjoin递归 long middle = (start + end)/2; ForkJoinTest task1 = new ForkJoinTest(start, middle); task1.fork(); //拆分任务，把任务压入线程队列 ForkJoinTest task2 = new ForkJoinTest(middle+1, end); task2.fork(); //同理 return task1.join() + task2.join(); } } } 测试类：package com.sw.forkjoin; import java.util.concurrent.ExecutionException; import java.util.concurrent.ForkJoinPool; import java.util.concurrent.ForkJoinTask; import java.util.stream.LongStream; /** * @Author suaxi * @Date 2021/2/16 17:37 */ public class Test { public static void main(String[] args) throws ExecutionException, InterruptedException { //test01(); //计算时间=7166 //test02(); //计算时间=5244 test03(); //计算时间=312 } //常规计算方法 public static void test01(){ Long sum =0L; long start = System.currentTimeMillis(); for (Long i = 1L; i < 10_0000_0000; i++) { sum += i; } long end = System.currentTimeMillis(); System.out.println("sum="+sum+" 计算时间="+ (end - start)); } //ForkJoin public static void test02() throws ExecutionException, InterruptedException { long start = System.currentTimeMillis(); //1、通过ForkJoinPool执行 ForkJoinPool forkJoinPool = new ForkJoinPool(); ForkJoinTask<Long> task = new ForkJoinTest(0L, 10_0000_0000L); //2、计算任务forkjoinPool.execute(ForkJoinTask task) ForkJoinTask<Long> submit = forkJoinPool.submit(task); Long sum = submit.get(); long end = System.currentTimeMillis(); System.out.println("sum="+sum+" 计算时间="+ (end - start)); } //Stream并行流 public static void test03(){ long start = System.currentTimeMillis(); //parallel并行 Long sum = LongStream.rangeClosed(0L,10_0000_0000L).parallel().reduce(0,Long::sum); long end = System.currentTimeMillis(); System.out.println("sum="+sum+" 计算时间="+ (end - start)); } }