1.分支合并 (大数据量的去使用)
package com.kuang.forkjoin;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import java.util.function.LongBinaryOperator;
import java.util.stream.LongStream;
/**
* 程序员分3000 6000(forkjoin) 9000(Stream 并行流) 等
*/
public class Test {
public static void main(String[] args) throws ExecutionException, InterruptedException {
// test1();11705ms
// test2();7077ms
test3();//207ms
}
//普通程序员 11705
public static void test1(){
long start = System.currentTimeMillis();
Long sum=0L;
for (Long i = 1L; i < 10_0000_0000; i++) {
sum+=i;
}
long end = System.currentTimeMillis();
System.out.println("sum="+sum+"时间:"+(end-start));
}
//会使用ForkJoin的 7077
public static void test2() throws ExecutionException, InterruptedException {
long start = System.currentTimeMillis();
ForkJoinPool forkJoinPool = new ForkJoinPool();
ForkJoinTask<Long> task = new ForkJoinDemo(0l, 10_0000_0000l);
ForkJoinTask<Long> submit = forkJoinPool.submit(task);//提交任务
Long sum = submit.get();
//forkJoinPool.execute(task);
// Long aLong = task.get();//拿到返回值
long end = System.currentTimeMillis();
System.out.println("sum="+sum+"时间:"+(end-start));
}
//Steam并行流
public static void test3(){
long start = System.currentTimeMillis();
//range() (]
long reduce = LongStream.rangeClosed(1L, 10_0000_0000L).parallel().reduce(0, Long::sum);
//1+到1000000000L
long end = System.currentTimeMillis();
System.out.println("sum="+reduce+"时间:"+(end-start));
}
}