思路：先计算每个线程计算的数据范围，使用线程计数器，所有线程计算结束后累加
代码语言：javascript复制import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.SynchronousQueue;
/**
* @author Zing
* @create 2022-11-07 14:17
*/
public class MyThread {
private List list1 = new ArrayList();
private List list2 = new ArrayList();
// 分段求和
public long sum(long start,long n){
long sum = 0;
for(long i = start;i <= n;i ){
sum = i;
}
return sum;
}
public void sum(){
long sum = 0;
for (Object o : list1) {
sum = (long) o;
}
System.out.println(sum);
}
// list2记录每个线程的第一个和最后一个数字
public void divide(long n,long x){
long block = n / x;
long temp = block;
long j = 1;
for (long m = 1;m <= x;m ){
list2.add(j);
list2.add(temp);
j = temp 1;
temp = block * (m 1);
}
}
public void sunFirst(long n,long x) throws InterruptedException {
divide(n,x);
CountDownLatch countDownLatch =new CountDownLatch(list2.size() / 2);
for(int h = 1;h < list2.size();h =2){
int finalH = h;
new Thread(()->{
long realSum = sum((long) list2.get(finalH - 1),(long) list2.get(finalH));
System.out.println("real sum" finalH ":" realSum);
list1.add(realSum);
countDownLatch.countDown();
}).start();
}
countDownLatch.await();
System.out.println("success");
sum();
}
}测试：
代码语言：javascript复制public class test {
public static void main(String[] args) throws InterruptedException {
MyThread myThread = new MyThread();
myThread.sunFirst(10000,10);
}
}计算十亿暴力时间戳差为370，十个线程仅90，这不是最佳匹配，要考虑线程切换资源适配合适的线程数量，但是多线程始终比暴力快
