redis优化秒杀

---
--- Generated by EmmyLua(https://github.com/EmmyLua)
--- Created by 34650.
--- DateTime: 2025/12/30 下午8:29
---

local voucherId = ARGV[1]
local userId = ARGV[2]

local stockKey = 'seckill:stock:' .. voucherId

local orderKey = 'seckill:order:' .. voucherId
-- 判断库存是否充足
if(tonumber(redis.call('get',stockKey)) <=0) then
    return 1
end
-- 判断用户是否下单
if(redis.call('sismember',orderKey,userId) ==1) then
    return 2
end
--扣库存
redis.call('incrby',stockKey,-1)
--下单（保存用户）
redis.call('sadd',orderKey,userId)

return 0

package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author ztn
 * @since 2025-09-23
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    private final BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    private final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }
    private class VoucherOrderHandler implements Runnable {

        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取队列中的订单
                    VoucherOrder voucherOrder = orderTasks.take();
                    // 2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (InterruptedException e) {
                    log.error("处理订单异常",e);
                }

            }

        }
    }

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        // 获取用户
        Long userId = voucherOrder.getUserId();
         //创建锁对象
//        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        // 获取锁
        boolean isLock = lock.tryLock();
        // 判断是否获取锁成功
        if(!isLock){
            // 获取锁失败，返回错误或重试
            log.error("不允许重复下单");
        }
        try {
             proxy.createVoucherOrder(voucherOrder);
        }finally {
            // 释放锁
            lock.unlock();
        }
    }
    private IVoucherOrderService proxy;

    @Override
    public Result seckillVocher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString()
        );
        //判断结果是否为0
        int r =result.intValue();
        if(r !=0){
            return Result.fail(r ==1?"库存不足":"不能重复下单");
        }
        //为0，有购买资格，把下单信息保存到阻塞队列

        VoucherOrder voucherOrder = new VoucherOrder();
        long orderId = redisIdWorker.nextId("order");

        voucherOrder.setId(orderId);

        voucherOrder.setUserId(userId);

        voucherOrder.setVoucherId(voucherId);

        //创建阻塞队列
        orderTasks.add(voucherOrder);
        // 获取代理对象（事务）
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //返回订单id
        return Result.ok(orderId);

    }
//    @Override
//    public Result seckillVocher(Long voucherId) {
//        // 1.查询优惠券
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        // 2.判断秒杀是否开始
//        if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
//            return Result.fail("秒杀尚未开始");
//        }
//        // 3.判断秒杀是否结束
//        if(voucher.getEndTime().isBefore(LocalDateTime.now())){
//            return Result.fail("秒杀已经结束");
//        }
//        // 4.判断库是否充足
//        if(voucher.getStock() < 1){
//            return Result.fail("库存不足");
//        }
//
//        Long userId = UserHolder.getUser().getId();
//        // 创建锁对象
////        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        // 获取锁
//        boolean isLock = lock.tryLock();
//        // 判断是否获取锁成功
//        if(!isLock){
//            // 获取锁失败，返回错误或重试
//            return Result.fail("不允许重复下单");
//        }
//        try {
//            // 获取代理对象（事务）
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        }finally {
//            // 释放锁
//            lock.unlock();
//        }
//    }
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        // 5.一人一单
        Long userId = voucherOrder.getUserId();
        // 5.1 查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder).count();
        // 5.2 判断是否存在
        if(count > 0){
            // 用户已经购买过了

            log.error("用户已经购买过一次了");
        }
        // 6.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1") // set stock =stock -1
                .eq("voucher_id", voucherOrder)
//                .eq("stock",voucher.getStock()) // where id = ? and stock = ?
                .gt("stock",0) // where id = ? and stock > 0
                .update();

        if(!success){
            log.error("库存不足");
        }
        save(voucherOrder);

    }
}