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ruoyi-cai/src/main/java/com/ruoyi/cai/lottery/LotteryService.java

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+package com.ruoyi.cai.lottery;
+
+import com.lottery.entity.Prize;
+import com.lottery.entity.UserDrawRecord;
+import com.lottery.mapper.UserDrawRecordMapper;
+import com.ruoyi.cai.domain.PrizeInfo;
+import com.ruoyi.cai.service.PrizeOnlineService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.redis.core.RedisTemplate;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.Random;
+import java.util.concurrent.locks.ReentrantLock;
+
+@Service
+public class LotteryService {
+
+    private static final Long THANKS_PRIZE_ID = 1L;
+    private static final String USER_DRAW_COUNT_KEY = "user:draw:count:%s";
+    // 每个用户的锁，防止并发抽奖（单机版用ReentrantLock）
+    private final ReentrantLock lock = new ReentrantLock();
+
+    @Autowired
+    private PrizeOnlineService prizeOnlineService;
+    @Autowired
+    private RedisTemplate<String, Object> redisTemplate;
+
+    /**
+     * 用户抽奖
+     */
+    public PrizeInfo draw(Long userId) {
+        // 加锁防止并发抽奖
+        lock.lock();
+        try {
+            // 1. 获取用户累计抽数
+            int continuousDraws = getContinuousDraws(userId);
+            int newContinuousDraws = continuousDraws + 1;
+
+            // 2. 获取启用的奖品（排除谢谢惠顾）
+            List<Prize> prizes = prizeService.getEnablePrizesExcludeThanks();
+            if (prizes.isEmpty()) {
+                // 只有谢谢惠顾
+                saveDrawRecord(userId, THANKS_PRIZE_ID, newContinuousDraws);
+                return prizeService.getPrizeFromCache(THANKS_PRIZE_ID);
+            }
+
+            // 3. 处理抽奖规则（保底、最低中奖抽数、中奖率）
+            Prize winPrize = null;
+            boolean isGuarantee = false;
+
+            // 3.1 检查保底规则
+            for (Prize prize : prizes) {
+                if (prize.getGuaranteeDraws() > 0 && newContinuousDraws >= prize.getGuaranteeDraws()) {
+                    // 触发保底，直接中该奖品
+                    if (prizeService.deductStock(prize.getId())) {
+                        winPrize = prize;
+                        isGuarantee = true;
+                        break;
+                    }
+                }
+            }
+
+            // 3.2 未触发保底，按中奖率和最低中奖抽数规则抽奖
+            if (winPrize == null) {
+                winPrize = randomDraw(prizes, newContinuousDraws);
+            }
+
+            // 4. 处理中奖结果
+            Long prizeId = winPrize != null ? winPrize.getId() : THANKS_PRIZE_ID;
+            int finalContinuousDraws = winPrize != null ? 0 : newContinuousDraws; // 中奖后重置累计抽数
+
+            // 5. 保存抽奖记录
+            saveDrawRecord(userId, prizeId, finalContinuousDraws);
+
+            // 6. 更新用户累计抽数缓存
+            updateContinuousDrawsCache(userId, finalContinuousDraws);
+
+            return prizeService.getPrizeFromCache(prizeId);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * 随机抽奖（处理中奖率和最低中奖抽数）
+     */
+    private Prize randomDraw(List<Prize> prizes, int continuousDraws) {
+        // 计算总中奖率
+        double totalProbability = 0.0;
+        for (Prize prize : prizes) {
+            // 检查最低中奖抽数规则：未达到则该奖品中奖率为0
+            if (continuousDraws < prize.getMinWinDraws()) {
+                continue;
+            }
+            totalProbability += prize.getWinProbability();
+        }
+
+        if (totalProbability <= 0) {
+            // 所有奖品都未达到最低中奖抽数，返回null（谢谢惠顾）
+            return null;
+        }
+
+        // 随机数（0-总中奖率）
+        double random = new Random().nextDouble() * totalProbability;
+        double current = 0.0;
+
+        for (Prize prize : prizes) {
+            if (continuousDraws < prize.getMinWinDraws()) {
+                continue;
+            }
+            current += prize.getWinProbability();
+            if (random <= current) {
+                // 抽中该奖品，检查库存
+                if (prizeService.deductStock(prize.getId())) {
+                    return prize;
+                } else {
+                    // 库存不足，重新抽奖（递归）
+                    return randomDraw(prizes, continuousDraws);
+                }
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * 获取用户累计抽数（缓存+数据库）
+     */
+    private int getContinuousDraws(Long userId) {
+        String key = String.format(USER_DRAW_COUNT_KEY, userId);
+        // 先从缓存获取
+        Integer count = (Integer) redisTemplate.opsForValue().get(key);
+        if (count != null) {
+            return count;
+        }
+        // 从数据库查询
+        count = userDrawRecordMapper.selectLastContinuousDraws(userId);
+        count = count == null ? 0 : count;
+        // 存入缓存
+        redisTemplate.opsForValue().set(key, count);
+        return count;
+    }
+
+    /**
+     * 更新用户累计抽数缓存
+     */
+    private void updateContinuousDrawsCache(Long userId, int count) {
+        String key = String.format(USER_DRAW_COUNT_KEY, userId);
+        redisTemplate.opsForValue().set(key, count);
+    }
+
+    /**
+     * 保存抽奖记录
+     */
+    @Transactional(rollbackFor = Exception.class)
+    private void saveDrawRecord(Long userId, Long prizeId, int continuousDraws) {
+        UserDrawRecord record = new UserDrawRecord();
+        record.setUserId(userId);
+        record.setPrizeId(prizeId);
+        record.setDrawTime(LocalDateTime.now());
+        record.setContinuousDraws(continuousDraws);
+        userDrawRecordMapper.insert(record);
+    }
+}