Java实现高并发秒杀的几种方式

@Cacheable(value = "goods", key = "#goodsId")
public Goods getGoods(Integer goodsId) {
    // 查询数据库
}

var requestTimes = 0; 
var lastRequestTime = 0;
function requestSecKill() {
    var now = new Date();
    if (now - lastRequestTime < 1000 && requestTimes > 5) {
        alert('请求过于频繁,请稍后再试!');
        return;
    }
    lastRequestTime = now;
    requestTimes++;
    // 发送秒杀请求
}

BlockingQueue<Runnable> queue = new ArrayBlockingQueue<>(1000);
​
public void addTask(Runnable task) {
    boolean offered = queue.offer(task);
    if (!offered) {
        // 队列满了,请求太多,返回限流提示
    }
}
​
public void handleTasks() {
    Runnable task = queue.poll();
    if (task != null) {
        executor.execute(task);
    }
}

RateLimiter rateLimiter = RateLimiter.create(10); // 每秒不超过10个请求 
if (rateLimiter.tryAcquire()) {
    // 请求通过
} else {
   // 请求超过限流频率
}

@Autowired
private GoodsRepository goodsRepository;
​
public Goods getGoods(Integer goodsId) {
    // 读取从库
    return goodsRepository.read(goodsId); 
}
​
public void reduceStock(Integer goodsId) {
    // 写入主库
    goodsRepository.write(goodsId);
}

@Cacheable(value = "goods", key = "#goodsId", expire = "#expireTime")
public Goods getGoods(Integer goodsId, Integer expireTime) {
    // 查询数据库
}
​
// 调整失效时间
cacheManager.setCacheExpired(cacheName, expireTime); 

@Cacheable(value = "goods", key = "#goodsId + #version") 
public Goods getGoods(Integer goodsId, Integer version) {
    // 查询数据库,带版本号校验
}
​
public void updateGoods(Integer goodsId, Integer version) {
    goods.setVersion(version + 1);
    // 更新数据库  
}

$.get("/goods/" + goodsId + "?v=" + version, function(data) {
     // 处理返回结果
});