java多线程-练习

需求

在这里插入图片描述

代码

使用Callable 方便返回执行的结果：每个线程的发送礼物的数量
礼物清单：共享资源，方便上锁
礼物数量：线程变量，每个线程发送礼物的数量

public class SendGiftThread implements Callable<Integer> {

    // 共享资源 礼物清单
    private ArrayList<String> giftList;
    // 此线程已经送出的礼物数量
    private int count = 0;

    public SendGiftThread(ArrayList<String> giftList) {
        this.giftList = giftList;
    }

    public int getCount() {
        return count;
    }


    @Override
    public Integer call() throws Exception {
        Random random = new Random();
        while (giftList.size() > 10){
            // 锁住的不一定是this，一定要是共享资源
            synchronized (giftList){
                // 礼物大于10个时，随机送出一个礼物
                if (giftList.size() > 10){
                    int index = random.nextInt(giftList.size());
                    // 送出礼物
                    String remove = giftList.remove(index);
                    // 送出礼物数量+1
                    count++;
                    System.out.println(Thread.currentThread().getName() + "送出了" + remove + "，已送出" + count + "个礼物");
                }
            }
        }
        return count;
    }
}

创建两个Callable对象
使用未来任务FutureTask进行封装
创建两个线程

public static void main(String[] args) {
    // 随机生成100个礼物
    ArrayList<String> giftList = new ArrayList<>();
    String[] names = {"口红", "手机", "电脑", "手表", "鞋子", "衣服", "裤子", "帽子", "围巾", "手套", "袜子", "饰品", "包包", "眼镜", "钱包", "皮带", "项链", "手链", "戒指", "耳环"};
    Random random = new Random();
    for (int i = 0; i < 100; i++) {
        giftList.add(names[random.nextInt(names.length)]+"-"+i);
    }

    // 创建两个任务
    SendGiftThread sendGiftThread1 = new SendGiftThread(giftList);
    SendGiftThread sendGiftThread2 = new SendGiftThread(giftList);
    Future<Integer> future1 = new FutureTask<>(sendGiftThread1);
    Future<Integer> future2 = new FutureTask<>(sendGiftThread2);
    // 创建两个线程
    Thread thread1 = new Thread((Runnable) future1, "小红");
    Thread thread2 = new Thread((Runnable) future2, "小明");
    // 启动线程
    thread1.start();
    thread2.start();

    // 打印线程返回结果
    try {
        System.out.println("小红送出了" + future1.get() + "个礼物");
        System.out.println("小明送出了" + future2.get() + "个礼物");
    } catch (Exception e) {
        e.printStackTrace();
    }



}