Question

java中怎样实现多线程执行的结果相加

Answer 1

import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
/**
单独的计算线程，比如计算{1...10}的相加

@author zhaohb
*/
public class CounterThread extends Thread{
private int start;
private int end;
private CyclicBarrier barrier ;
public CounterThread(int id,int start, int end,CyclicBarrier barrier) {
this.start = start;
this.end = end;
this.barrier = barrier;
setName("Thread-"+id+" ");
}

@Override
public void run() {
int count = 0;
for(int i=start;i<end+1;i++){
count += i;
}
Counter.totalCount(count);
try {
barrier.await();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (BrokenBarrierException e) {
e.printStackTrace();
}
}
}

import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**

测试类入口

@author zhaohb
*/
public class CounterTest {

public static void main(String[] args) {
//CyclicBarrier指定了当10个线程运行结束时候，可以进行最后结果展示了
CyclicBarrier barrier = new CyclicBarrier(10,new TotalTask(new Counter()));
ExecutorService executorService = Executors.newCachedThreadPool();
for(int i=0;i<10;i++){
int start = i*10+1;
int end = start + 9;
CounterThread counterThread = new CounterThread(i,start, end,barrier);
executorService.execute(counterThread);
}
executorService.shutdown();
}
}

/**

线程结果计算：将单独的线程的计算的结果相加，汇总的到总的结果

@author zhaohb
*
*/
class Counter {

private static int count =0;
public synchronized static int totalCount(int perCount){
count += perCount;
return count;
}

public int totalResult(){
return count;
}

}
/**

最后结算展示线程

@author zhb
*
*/
class TotalTask implements Runnable{
private Counter counter ;
public TotalTask(Counter counter){
this.counter = counter;
}

@Override
public void run() {
System.out.println("所有线程运行完毕，总结果为：");

int total = counter.totalResult();
System.out.println(total);
}
}

Answer 2

定义一个成员变量，在线程里加到成员变量里就好了。

追问

我找到题目的答案了，要吗？

追答

可以啊。

追问

你可以上book.boxuegu.com/java上去下载

追答

嗯