JAVA8-Fork Join JAVA8-Fork JoinFork：将一个任务拆分成多个线程执行。Join：将每个现场结果join，最后得到结果。范例：求数组总和前置数据：public static int[] data = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};1、原始实现方式 public static int calc() { int result = 0; for (int i = 0; i < data.length; i++) { result += data[i]; } return result; }原始实现方式调用：System.out.println("result=> " + calc());2、RecursiveTask实现RecursiveTask有返回值。package com.example.study.java8.forkjoin; import lombok.AllArgsConstructor; import lombok.Data; import lombok.NoArgsConstructor; import lombok.ToString; import java.util.concurrent.RecursiveTask; @Data @AllArgsConstructor @NoArgsConstructor @ToString public class AccumulatorRecursiveTask extends RecursiveTask<Integer> { private int start; private int end; private int[] data; private int LIMIT=3; public AccumulatorRecursiveTask(int start, int end, int[] data) { this.start = start; this.end = end; this.data = data; } @Override protected Integer compute() { //如果小于3个就可以直接进行计算了，否则fork成多个，再计算 if(end -start <LIMIT) { int result =0; for(int i=start;i<end;i++){ result+=data[i]; } return result; } int mid = (start+end)/2; AccumulatorRecursiveTask left = new AccumulatorRecursiveTask(start,mid,data); AccumulatorRecursiveTask right = new AccumulatorRecursiveTask(mid,end,data); left.fork(); Integer rightResult = right.compute(); Integer leftResult = left.join(); return rightResult+leftResult; } } RecursiveTask调用： AccumulatorRecursiveTask task = new AccumulatorRecursiveTask(0, data.length, data); ForkJoinPool forkJoinPool = new ForkJoinPool(); Integer result = forkJoinPool.invoke(task); System.out.println("AccumulatorRecursiveTask result => " + result);3、RecursiveAction实现RecursiveAction:无返回值package com.example.study.java8.forkjoin; import lombok.AllArgsConstructor; import lombok.Data; import lombok.NoArgsConstructor; import lombok.ToString; import java.util.concurrent.RecursiveAction; import java.util.concurrent.atomic.AtomicInteger; @Data @AllArgsConstructor @NoArgsConstructor @ToString public class AccumulatorRecursiveAction extends RecursiveAction { private int start; private int end; private int[] data; private int LIMIT = 3; public AccumulatorRecursiveAction(int start, int end, int[] data) { this.start = start; this.end = end; this.data = data; } @Override protected void compute() { //如果小于3个就可以直接进行计算了，否则fork成多个，再计算 if (end - start < LIMIT) { for (int i = start; i < end; i++) { AccumulatorHelper.accumulate(data[i]); } } else { int mid = (start + end) / 2; AccumulatorRecursiveAction left = new AccumulatorRecursiveAction(start, mid, data); AccumulatorRecursiveAction right = new AccumulatorRecursiveAction(mid, end, data); right.fork(); left.fork(); right.join(); left.join(); } } static class AccumulatorHelper { private static final AtomicInteger result = new AtomicInteger(0); static void accumulate(int value) { result.getAndAdd(value); } public static int getResult() { return result.get(); } static void rest() { result.set(0); } } } RecursiveAction调用： AccumulatorRecursiveAction action = new AccumulatorRecursiveAction(0, data.length, data); forkJoinPool.invoke(action); System.out.println("AccumulatorRecursiveAction result => " + AccumulatorRecursiveAction.AccumulatorHelper.getResult());最后输出结果result=> 55 AccumulatorRecursiveTask result => 55 AccumulatorRecursiveAction result => 55