J250511/01-JavaSE阶段代码/J20250801/homework/Demo07.java

package J20250801.homework;

import java.util.ArrayList;
import java.util.Random;
import java.util.concurrent.*;

/**
 * @author WanJl
 * @version 1.0
 * @title Demo07
 * @description
 * @create 2025/8/1
 */
public class Demo07 {
    private static Random ran=new Random();
    /**
     * 模拟计算用户月度消费
     * @param userId    用户id
     * @return  消费金额(1000~5000)
     */
    public static int getMonthlyConsumption(int userId) throws InterruptedException {
        //模拟计算耗时1~2秒
        int i=1000+ran.nextInt(1001);
        Thread.sleep(i);
        //模拟生成随机消费金额
        int amount=1000+ran.nextInt(4001);
        System.out.println("用户"+userId+"的月度消费计算完成："+amount+"元");
        return amount;
    }

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        ExecutorService pool = Executors.newCachedThreadPool();
        ArrayList<Future<Integer>> list=new ArrayList<>();
        //提交5个用户的消费计算任务
        for (int i = 0; i < 5; i++) {
            final int userId=i+1;
            Future<Integer> future=pool.submit(()-> getMonthlyConsumption(userId));
            list.add(future);
        }
        //等待所有任务全部完成后收集结果
        int total=0;
        StringBuilder sb=new StringBuilder();
        for (int i = 0; i < list.size(); i++) {
            final int userId=i+1;
            Integer amount = list.get(i).get();
            total+=amount;
            sb.append("用户"+userId+"="+amount);
            if (i<list.size()-1){
                sb.append(",");
            }
        }
        System.out.println("所有用户总共消费："+total+"元，用户消费明细："+sb);

        pool.shutdown();
        if (!pool.awaitTermination(3, TimeUnit.SECONDS)){
            pool.shutdownNow();
        }
    }

}