使用Redission实现抢红包
业务描述：发起红包，规定好总金额100，红包个数10。发完红包后，1秒钟内100个人同时抢。
需要注意的点：
1.数据库瞬时压力过大，需采用缓存；
2.线程并发进行，避免超卖；
处理：使用redis配合Redission加锁的方式，sexnx也可实现。
表设计：
列依次为：红包总金额，领取总人数，当前领取红包金额，当前领取人数
pom.xml
<!--redis--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> </dependency> <!-- Redisson 实现分布式锁 --> <dependency> <groupId>org.redisson</groupId> <artifactId>redisson</artifactId> <version>3.16.8</version> </dependency>
application.yml
spring:
redis:
database: 0
host: ${ip}
port: 6379
password: 123456
redisson:
address: redis://${ip}:6379
password: 123456
自动装载部分
RedisConfig.java
package com.example.cisum.config; import lombok.Value; import org.springframework.cache.annotation.CachingConfigurerSupport; import org.springframework.cache.annotation.EnableCaching; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.data.redis.connection.RedisConnectionFactory; import org.springframework.data.redis.core.RedisTemplate; import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer; import org.springframework.data.redis.serializer.RedisSerializer; import org.springframework.data.redis.serializer.StringRedisSerializer; @Configuration @EnableCaching public class RedisConfig extends CachingConfigurerSupport { @Bean(name = "redisTemplate") public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) { RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>(); //参照StringRedisTemplate内部实现指定序列化器 redisTemplate.setConnectionFactory(redisConnectionFactory); redisTemplate.setKeySerializer(keySerializer()); redisTemplate.setHashKeySerializer(keySerializer()); redisTemplate.setValueSerializer(valueSerializer()); redisTemplate.setHashValueSerializer(valueSerializer()); return redisTemplate; } private RedisSerializer<String> keySerializer() { return new StringRedisSerializer(); } //使用Jackson序列化器 private RedisSerializer<Object> valueSerializer() { return new GenericJackson2JsonRedisSerializer(); } }
RedissonConfig.java
package com.example.cisum.config; import com.example.cisum.utils.RedisLockUtil; import org.apache.commons.lang3.StringUtils; import org.redisson.Redisson; import org.redisson.api.RedissonClient; import org.redisson.config.Config; import org.redisson.config.SingleServerConfig; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.autoconfigure.condition.ConditionalOnClass; import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty; import org.springframework.boot.context.properties.EnableConfigurationProperties; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; @Configuration @ConditionalOnClass(Config.class) @EnableConfigurationProperties(RedissonProperties.class) public class RedissonConfig { @Autowired private RedissonProperties redssionProperties; /** * 单机模式自动装配 * * @return */ @Bean @ConditionalOnProperty(name = "redisson.address") RedissonClient redissonSingle() { Config config = new Config(); SingleServerConfig serverConfig = config.useSingleServer() .setAddress(redssionProperties.getAddress()) .setTimeout(redssionProperties.getTimeout()) .setConnectionPoolSize(redssionProperties.getConnectionPoolSize()) .setConnectionMinimumIdleSize(redssionProperties.getConnectionMinimumIdleSize()); if (StringUtils.isNotBlank(redssionProperties.getPassword())) { serverConfig.setPassword(redssionProperties.getPassword()); } return Redisson.create(config); } /** * 装配locker类，并将实例注入到RedissLockUtil中 * * @return */ @Bean RedisLockUtil redissLockUtil(RedissonClient redissonClient) { RedisLockUtil redissLockUtil = new RedisLockUtil(); redissLockUtil.setRedissonClient(redissonClient); return redissLockUtil; } }
工具类：
RedisLockUtil.java
package com.example.cisum.utils; import org.redisson.api.RLock; import org.redisson.api.RMapCache; import org.redisson.api.RedissonClient; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.util.DigestUtils; import java.util.concurrent.TimeUnit; /** * redis分布式锁帮助类 * * @author 姜通通 */ public class RedisLockUtil { @Autowired private static RedissonClient redissonClient; public void setRedissonClient(RedissonClient locker) { redissonClient = locker; } /** * 加锁 * * @param lockKey * @return */ public static RLock lock(String lockKey) { RLock lock = redissonClient.getLock(lockKey); lock.lock(); return lock; } /** * 释放锁 * * @param lockKey */ public static void unlock(String lockKey) { RLock lock = redissonClient.getLock(lockKey); if (lock.isLocked() && lock.isHeldByCurrentThread()) { lock.unlock(); } } /** * 释放锁 * * @param lock */ public static void unlock(RLock lock) { lock.unlock(); } /** * 带超时的锁 * * @param lockKey * @param timeout 超时时间 单位：秒 */ public static RLock lock(String lockKey, int timeout) { RLock lock = redissonClient.getLock(lockKey); lock.lock(timeout, TimeUnit.SECONDS); return lock; } /** * 带超时的锁 * * @param lockKey * @param unit 时间单位 * @param timeout 超时时间 */ public static RLock lock(String lockKey, TimeUnit unit, int timeout) { RLock lock = redissonClient.getLock(lockKey); lock.lock(timeout, unit); return lock; } /** * 尝试获取锁 * * @param lockKey * @param waitTime 最多等待时间 * @param leaseTime 上锁后自动释放锁时间 * @return */ public static boolean tryLock(String lockKey, int waitTime, int leaseTime) { RLock lock = redissonClient.getLock(lockKey); try { return lock.tryLock(waitTime, leaseTime, TimeUnit.SECONDS); } catch (InterruptedException e) { return false; } } /** * 尝试获取锁 * * @param lockKey * @param unit 时间单位 * @param waitTime 最多等待时间 * @param leaseTime 上锁后自动释放锁时间 * @return */ public static boolean tryLock(String lockKey, TimeUnit unit, int waitTime, int leaseTime) { RLock lock = redissonClient.getLock(buildKey(lockKey)); try { return lock.tryLock(waitTime, leaseTime, unit); } catch (InterruptedException e) { return false; } } /** * 初始红包数量 * * @param key * @param count */ public void initCount(String key, int count) { RMapCache<String, Integer> mapCache = redissonClient.getMapCache("skill"); mapCache.putIfAbsent(key, count, 3, TimeUnit.DAYS); } /** * 递增 * * @param key * @param delta 要增加几(大于0) * @return */ public int incr(String key, int delta) { RMapCache<String, Integer> mapCache = redissonClient.getMapCache("skill"); if (delta < 0) { throw new RuntimeException("递增因子必须大于0"); } return mapCache.addAndGet(key, 1);//加1并获取计算后的值 } /** * 递减 * * @param key 键 * @param delta 要减少几(小于0) * @return */ public int decr(String key, int delta) { RMapCache<String, Integer> mapCache = redissonClient.getMapCache("skill"); if (delta < 0) { throw new RuntimeException("递减因子必须大于0"); } return mapCache.addAndGet(key, -delta);//加1并获取计算后的值 } private static String buildKey(String key) { return DigestUtils.md5DigestAsHex(key.getBytes()); } }
RedisUtil.java
package com.example.cisum.utils; /** * Redis工具类 * * @author 姜通通 * @date 2021年5月22日 */ import com.alibaba.fastjson.JSONObject; import org.apache.commons.lang3.ObjectUtils; import org.apache.poi.ss.formula.functions.T; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.data.redis.core.RedisTemplate; import org.springframework.data.redis.core.ZSetOperations; import org.springframework.stereotype.Component; import org.springframework.util.DigestUtils; import java.util.Map; import java.util.Set; import java.util.concurrent.TimeUnit; @Component public final class RedisUtil { @Autowired private RedisTemplate<String, Object> redisTemplate; // ================================String================================= public boolean set(String key, Object value) { try { redisTemplate.opsForValue().set(buildKey(key), value); return true; } catch (Exception e) { e.printStackTrace(); return false; } } /** * 普通缓存放入并设置时间 * * @param key 键 * @param value 值 * @param time 时间(秒) time要大于0 如果time小于等于0 将设置无限期 * @return true成功 false 失败 */ public boolean set(String key, Object value, long time) { try { if (time > 0) { redisTemplate.opsForValue().set(buildKey(key), value, time, TimeUnit.SECONDS); } else { set(buildKey(key), value); } return true; } catch (Exception e) { e.printStackTrace(); return false; } } public Object get(String key) { return key == null ? null : redisTemplate.opsForValue().get(buildKey(key)); } public <T>T get(String key,Class<T> obj) { if(key == null)return null; Object o = redisTemplate.opsForValue().get(buildKey(key)); if(ObjectUtils.isEmpty(o))return null; T t = JSONObject.parseObject(o.toString(), obj); return t; } /** * 指定缓存失效时间 * * @param key 键 * @param time 时间(秒) * @return */ public boolean expire(String key, long time) { try { if (time > 0) { redisTemplate.expire(buildKey(key), time, TimeUnit.SECONDS); } return true; } catch (Exception e) { e.printStackTrace(); return false; } } /** * 根据key 获取过期时间 * * @param key 键 不能为null * @return 时间(秒) 返回0代表为永久有效 */ public long getExpire(String key) { return redisTemplate.getExpire(buildKey(key), TimeUnit.SECONDS); } /** * 判断key是否存在 * * @param key 键 * @return true 存在 false不存在 */ public boolean hasKey(String key) { try { return redisTemplate.hasKey(buildKey(key)); } catch (Exception e) { e.printStackTrace(); return false; } } /** * 递增 * * @param key * @param delta 要增加几(大于0) * @return */ public long increment(String key, long delta) { if (delta < 0) { throw new RuntimeException("递增因子必须大于0"); } return redisTemplate.opsForValue().increment(buildKey(key), delta); } /** * 递减 * * @param key 键 * @param delta 要减少几(小于0) * @return */ public long decrement(String key, long delta) { if (delta < 0) { throw new RuntimeException("递减因子必须大于0"); } return redisTemplate.opsForValue().increment(buildKey(key), -delta); } // ================================zSet================================= /** * 添加元素,有序集合是按照元素的score值由小到大排列 * * @param key * @param value * @param score * @return */ public Boolean zAdd(String key, String value, double score) { return redisTemplate.opsForZSet().add(key, value, score); } /** * 增加元素的score值，并返回增加后的值 * * @param key * @param value * @param delta * @return */ public Double zIncrementScore(String key, String value, double delta) { return redisTemplate.opsForZSet().incrementScore(key, value, delta); } /** * 获取集合的元素, 从大到小排序 * * @param key * @param start * @param end * @return */ public Set<Object> zReverseRange(String key, long start, long end) { return redisTemplate.opsForZSet().reverseRange(key, start, end); } /** * 获取集合的元素, 从大到小排序, 并返回score值 * * @param key * @param start * @param end * @return */ public Set<ZSetOperations.TypedTuple<Object>> zReverseRangeWithScores(String key, long start, long end) { return redisTemplate.opsForZSet().reverseRangeWithScores(key, start, end); } // ================================Map================================= /** * HashGet * * @param key 键 不能为null * @param item 项 不能为null */ public Object hget(String key, String item) { try { return redisTemplate.opsForHash().get(buildKey(key), item); } catch (Exception e) { e.printStackTrace(); return null; } } /** * 获取hashKey对应的所有键值 * * @param key 键 * @return 对应的多个键值 */ public Map<Object, Object> hmget(String key) { try { return redisTemplate.opsForHash().entries(buildKey(key)); } catch (Exception e) { e.printStackTrace(); return null; } } /** * HashSet * * @param key 键 * @param map 对应多个键值 */ public boolean hmset(String key, Map<String, Object> map) { try { redisTemplate.opsForHash().putAll(buildKey(key), map); return true; } catch (Exception e) { e.printStackTrace(); return false; } } /** * HashSet 并设置时间 * * @param key 键 * @param map 对应多个键值 * @param time 时间(秒) * @return true成功 false失败 */ public boolean hmset(String key, Map<String, Object> map, long time) { try { redisTemplate.opsForHash().putAll(buildKey(key), map); if (time > 0) { expire(buildKey(key), time); } return true; } catch (Exception e) { e.printStackTrace(); return false; } } /** * 向一张hash表中放入数据,如果不存在将创建 * * @param key 键 * @param item 项 * @param value 值 * @return true 成功 false失败 */ public boolean hset(String key, String item, Object value) { try { redisTemplate.opsForHash().put(buildKey(key), item, value); return true; } catch (Exception e) { e.printStackTrace(); return false; } } /** * 向一张hash表中放入数据,如果不存在将创建 * * @param key 键 * @param item 项 * @param value 值 * @param time 时间(秒) 注意:如果已存在的hash表有时间,这里将会替换原有的时间 * @return true 成功 false失败 */ public boolean hset(String key, String item, Object value, long time) { try { redisTemplate.opsForHash().put(buildKey(key), item, value); if (time > 0) { expire(buildKey(key), time); } return true; } catch (Exception e) { e.printStackTrace(); return false; } } /** * 删除hash表中的值 * * @param key 键 不能为null * @param item 项 可以使多个 不能为null */ public void hdel(String key, Object... item) { redisTemplate.opsForHash().delete(buildKey(key), item); } /** * 判断hash表中是否有该项的值 * * @param key 键 不能为null * @param item 项 不能为null * @return true 存在 false不存在 */ public boolean hHasKey(String key, String item) { return redisTemplate.opsForHash().hasKey(buildKey(key), item); } /** * hash递增 如果不存在,就会创建一个 并把新增后的值返回 * * @param key 键 * @param item 项 * @param by 要增加几(大于0) */ public double hincr(String key, String item, double by) { return redisTemplate.opsForHash().increment(buildKey(key), item, by); } /** * hash递减 * * @param key 键 * @param item 项 * @param by 要减少记(小于0) */ public double hdecr(String key, String item, double by) { return redisTemplate.opsForHash().increment(buildKey(key), item, -by); } private static String buildKey(String key) { return DigestUtils.md5DigestAsHex(key.getBytes()); } }
实体：RedPacket.java
package com.example.cisum.domain; import com.baomidou.mybatisplus.annotation.TableName; import lombok.Data; @Data @TableName("tb_red_packet") public class RedPacket { private Long id;//主键 private int totalAmount;//红包总金额 private int totalNum;//红包总个数 private int actualAmount;//实际抢红包金额 private int actualNum;//实际抢红包个数 }
业务类：RedPacketServiceImpl.java
package com.example.cisum.service; import com.alibaba.fastjson.JSONObject; import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl; import com.example.cisum.domain.RedPacket; import com.example.cisum.mapper.RedPcketMapper; import com.example.cisum.utils.RedisUtil; import org.redisson.api.RLock; import org.redisson.api.RedissonClient; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import java.util.concurrent.TimeUnit; @Service public class RedPacketServiceImpl extends ServiceImpl<RedPcketMapper, RedPacket> implements RedPacketService { @Autowired(required = false) private RedPcketMapper redPcketMapper; @Autowired private RedisUtil redisUtil; @Autowired private RedissonClient redissonClient; private String createLcokKey(long id) { return String.format("LOCK:%s:%d", RedPacket.class, id); } private String createCacheKey(long id) { return String.format("CACHE:%s:%d", RedPacket.class, id); } public void initRedPacket(long id) { RedPacket redPacket = redPcketMapper.selectById(id); redisUtil.set(createCacheKey(id), JSONObject.toJSONString(redPacket)); } public RedPacket viewRedPacket(long id) { return redisUtil.get(createCacheKey(id), RedPacket.class); } public int start(long id) { RedPacket redPacket = redisUtil.get(createCacheKey(id), RedPacket.class); if (redPacket.getActualAmount() < redPacket.getTotalAmount() && redPacket.getActualNum() < redPacket.getTotalNum()) { redPacket.setActualAmount(redPacket.getActualAmount() + 10); redPacket.setActualNum(redPacket.getActualNum() + 1); redisUtil.set(createCacheKey(id), JSONObject.toJSONString(redPacket)); return 10; } return 0; } public int start2(long id) { RLock lock = redissonClient.getLock(createLcokKey(id)); try { boolean tryLock = lock.tryLock(5, 10, TimeUnit.SECONDS); if (tryLock) { RedPacket redPacket = redisUtil.get(createCacheKey(id), RedPacket.class); if (redPacket.getActualAmount() < redPacket.getTotalAmount() && redPacket.getActualNum() < redPacket.getTotalNum()) { redPacket.setActualAmount(redPacket.getActualAmount() + 10); redPacket.setActualNum(redPacket.getActualNum() + 1); redisUtil.set(createCacheKey(id), JSONObject.toJSONString(redPacket)); return 10; } } } catch (InterruptedException e) { e.printStackTrace(); } finally { if (lock.isLocked() && lock.isHeldByCurrentThread()) { lock.unlock(); } } return 0; } }
控制层：RedPacketController.java
package com.example.cisum.controller; import com.alibaba.fastjson.JSONObject; import com.example.cisum.domain.RedPacket; import com.example.cisum.service.RedPacketService; import com.example.cisum.utils.RedisLockUtil; import com.example.cisum.utils.RedisUtil; import org.redisson.api.RedissonClient; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RestController; import java.util.concurrent.TimeUnit; @RestController public class RedPacketController { @Autowired private RedPacketService redPacketService; @Autowired private RedisUtil redisUtils; @Autowired private RedissonClient redissonClient; @GetMapping("list/{id}") public String list(@PathVariable Long id) { return JSONObject.toJSONString(redPacketService.getById(id)); } @GetMapping("initRedPacket/{id}") public String initRedPacket(@PathVariable Long id) { redPacketService.initRedPacket(id); return JSONObject.toJSONString(redPacketService.viewRedPacket(id)); } @GetMapping("start/{id}") public int start(@PathVariable Long id) { return redPacketService.start(id); } @GetMapping("start2/{id}") public int start2(@PathVariable Long id) { return redPacketService.start2(id); } private int doStart(Long id) { int money = 0; boolean res = false; try { /** * 获取锁 */ res = RedisLockUtil.tryLock(id + "", TimeUnit.SECONDS, 3, 10); if (res) { Object redpacket = redisUtils.get("RED:" + id); if (redpacket == null) { return 0; } RedPacket redPacket = JSONObject.parseObject(redpacket.toString(), RedPacket.class); if (redPacket.getActualAmount() < redPacket.getTotalAmount() && redPacket.getActualNum() < redPacket.getTotalNum()) { redPacket.setActualAmount(redPacket.getActualAmount() + 10); redPacket.setActualNum(redPacket.getActualNum() + 1); redisUtils.set("RED:" + id, JSONObject.toJSONString(redPacket)); return 10; } } else { System.out.println(Thread.currentThread().getName() + "未获取到锁"); } } catch (Exception e) { e.printStackTrace(); } finally { //释放锁 if (res) { RedisLockUtil.unlock(id + ""); } } return 0; } }
测试：
初始化红包：http://localhost:8081/initRedPacket/1
设置JMeter
