redis分布式锁实现示例-IT俱乐部

1.需求

我们公司想实现一个简单的分布式锁，用于服务启动初始化执行init方法的时候，只执行一次，避免重复执行加载缓存规则的代码，还有预防高并发流程发起部分，产品超发，多发问题。所以结合网上信息，自己简单实现了一个redis分布式锁，可以进行单次资源锁定，排队锁定(没有实现权重，按照时间长短争夺锁信息)，还有锁定业务未完成，需要延期锁等简单方法，死锁则是设置过期时间即可。期间主要用到的技术为redis，延时线程池，LUA脚本，比较简单，此处记录一下，方便下次学习查看。

2.具体实现

整体配置相对简单，主要是编写redisUtil工具类，实现redis的简单操作，编写分布式锁类SimpleDistributeLock，主要内容都在此锁的实现类中，SimpleDistributeLock实现类主要实现方法如下：

1.一次抢夺加锁方法 tryLock
2.连续排队加锁方法tryContinueLock，此方法中间有调用线程等待Thread.sleep方法防止防止StackOverFlow异常，比较耗费资源，后续应该需要优化处理
3.重入锁tryReentrantLock，一个资源调用过程中，处于加锁状态仍然可以再次加锁，重新刷新其过期时间
4.刷新锁过期时间方法resetLockExpire
5.释放锁方法，注意，释放过程中需要传入加锁的value信息，以免高并发情况下多线程锁信息被其他线程释放锁操作误删

2.1 redis基本操作工具类redisUtil

package cn.git.redis;
 
import cn.hutool.core.util.IdUtil;
import cn.hutool.core.util.ObjectUtil;
import cn.hutool.core.util.StrUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.dao.DataAccessException;
import org.springframework.data.geo.*;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.RedisScript;
import org.springframework.util.CollectionUtils;
 
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;
 
/**
 * @program: bank-credit-sy
 * @description: 封装redis的工具类
 * @author: lixuchun
 * @create: 2021-01-23 11:53
 */
public class RedisUtil {
 
    /**
     * 模糊查询匹配
     */
    private static final String FUZZY_ENQUIRY_KEY = "*";
 
    @Autowired
    @Qualifier("redisTemplate")
    private RedisTemplate redisTemplate;
 
    public void setRedisTemplate(RedisTemplate redisTemplate) {
        this.redisTemplate = redisTemplate;
    }
 
    /**
     * 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(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(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(key);
        } catch (Exception e) {
            return false;
        }
    }
 
    /**
     * 删除缓存
     *
     * @param key 可以传一个值 或多个
     */
    @SuppressWarnings("unchecked")
    public void del(String... key) {
        if (key != null && key.length > 0) {
            if (key.length == 1) {
                redisTemplate.delete(key[0]);
            } else {
                redisTemplate.delete(CollectionUtils.arrayToList(key));
            }
        }
    }
 
    /**
     * 普通缓存获取
     *
     * @param key 键
     * @return 值
     */
    public Object get(String key) {
        return key == null ? null : redisTemplate.opsForValue().get(key);
    }
 
    /**
     * 普通缓存放入
     *
     * @param key   键
     * @param value 值
     * @return true成功 false失败
     */
    public boolean set(String key, Object value) {
        try {
            redisTemplate.opsForValue().set(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(key, value, time, TimeUnit.SECONDS);
            } else {
                set(key, value);
            }
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }
 
    /**
     * 如果不存在，则设置对应key,value 键值对,并且设置过期时间
     * @param key 锁key
     * @param value 锁值
     * @param time 时间单位second
     * @return 设定结果
     */
    /**
    public Boolean setNxEx(String key, String value, long time) {
        Boolean setResult = (Boolean) redisTemplate.execute((RedisCallback) connection -> {
            RedisStringCommands.SetOption setOption = RedisStringCommands.SetOption.ifAbsent();
            // 设置过期时间
            Expiration expiration = Expiration.seconds(time);
            // 执行setnx操作
            Boolean result = connection.set(key.getBytes(StandardCharsets.UTF_8),
                    value.getBytes(StandardCharsets.UTF_8), expiration, setOption);
            return result;
        });
        return setResult;
    }
     **/
 
    /**
     * 如果不存在，则设置对应key,value 键值对,并且设置过期时间
     * @param key 锁key
     * @param value 锁值
     * @param time 时间单位second
     * @return 设定结果
     */
    public Boolean setNxEx(String key, String value, long time) {
        return redisTemplate.opsForValue().setIfAbsent(key, value, time, TimeUnit.SECONDS);
    }
 
    /**
     * 递增
     *
     * @param key 键
     * @return
     */
    public long incr(String key, long delta) {
        if (delta  hmget(String key) {
        return redisTemplate.opsForHash().entries(key);
    }
 
    /**
     * 获取hashKey对应的所有键值
     *
     * @param key 键
     * @return 对应的多个键值
     */
    public List<object data-origwidth="" data-origheight="" style="width: 1264px;"> hmget(String key, List<object data-origwidth="" data-origheight="" style="width: 800px;"> itemList) {
        return redisTemplate.opsForHash().multiGet(key, itemList);
    }
 
    /**
     * 获取key对应的hashKey值
     *
     * @param key     键
     * @param hashKey 键
     * @return 对应的键值
     */
    public Object hmget(String key, String hashKey) {
        return redisTemplate.opsForHash().get(key, hashKey);
    }
 
    /**
     * HashSet
     *
     * @param key 键
     * @param map 对应多个键值
     * @return true 成功 false 失败
     */
    public boolean hmset(String key, Map map) {
        try {
            redisTemplate.opsForHash().putAll(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<object data-origwidth="" data-origheight="" style="width: 800px;"> map, long time) {
        try {
            redisTemplate.opsForHash().putAll(key, map);
            if (time > 0) {
                expire(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(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(key, item, value);
            if (time > 0) {
                expire(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(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(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)
     * @return
     */
    public double hincr(String key, String item, double by) {
        return redisTemplate.opsForHash().increment(key, item, by);
    }
 
    /**
     * hash递减
     *
     * @param key  键
     * @param item 项
     * @param by   要减少记(小于0)
     * @return
     */
    public double hdecr(String key, String item, double by) {
        return redisTemplate.opsForHash().increment(key, item, -by);
    }
 
    /**
     * 根据key获取Set中的所有值
     *
     * @param key 键
     * @return
     */
    public Set<object data-origwidth="" data-origheight="" style="width: 800px;"> sGet(String key) {
        try {
            return redisTemplate.opsForSet().members(key);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
 
    /**
     * 根据value从一个set中查询,是否存在
     *
     * @param key   键
     * @param value 值
     * @return true 存在 false不存在
     */
    public boolean sHasKey(String key, Object value) {
        try {
            return redisTemplate.opsForSet().isMember(key, value);
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }
 
    /**
     * 将数据放入set缓存
     *
     * @param key    键
     * @param values 值 可以是多个
     * @return 成功个数
     */
    public long sSet(String key, Object... values) {
        try {
            return redisTemplate.opsForSet().add(key, values);
        } catch (Exception e) {
            e.printStackTrace();
            return 0;
        }
    }
 
    /**
     * 将set数据放入缓存
     *
     * @param key    键
     * @param time   时间(秒)
     * @param values 值 可以是多个
     * @return 成功个数
     */
    public long sSetAndTime(String key, long time, Object... values) {
        try {
            Long count = redisTemplate.opsForSet().add(key, values);
            if (time > 0) {
                expire(key, time);
            }
            return count;
        } catch (Exception e) {
            e.printStackTrace();
            return 0;
        }
    }
 
    /**
     * 获取set缓存的长度
     *
     * @param key 键
     * @return
     */
    public long sGetSetSize(String key) {
        try {
            return redisTemplate.opsForSet().size(key);
        } catch (Exception e) {
            e.printStackTrace();
            return 0;
        }
    }
 
    /**
     * 移除值为value的
     *
     * @param key    键
     * @param values 值 可以是多个
     * @return 移除的个数
     */
    public long setRemove(String key, Object... values) {
        try {
            Long count = redisTemplate.opsForSet().remove(key, values);
            return count;
        } catch (Exception e) {
            e.printStackTrace();
            return 0;
        }
    }
 
    /**
     * 获取list缓存的内容
     *
     * @param key   键
     * @param start 开始
     * @param end   结束 0 到 -1代表所有值
     * @return
     */
    public List<object data-origwidth="" data-origheight="" style="width: 800px;"> lGet(String key, long start, long end) {
        try {
            return redisTemplate.opsForList().range(key, start, end);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
 
    /**
     * 获取list缓存的长度
     *
     * @param key 键
     * @return
     */
    public long lGetListSize(String key) {
        try {
            return redisTemplate.opsForList().size(key);
        } catch (Exception e) {
            e.printStackTrace();
            return 0;
        }
    }
 
    /**
     * 通过索引 获取list中的值
     *
     * @param key   键
     * @param index 索引 index>=0时， 0 表头，1 第二个元素，依次类推；index 0) {
                expire(key, time);
            }
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }
 
    /**
     * 将list放入缓存
     *
     * @param key   键
     * @param value 值
     * @return
     */
    public boolean lSet(String key, List<object data-origwidth="" data-origheight="" style="width: 800px;"> value) {
        try {
            redisTemplate.opsForList().rightPushAll(key, value);
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }
 
    /**
     * 将list放入缓存
     *
     * @param key   键
     * @param value 值
     * @param time  时间(秒)
     * @return
     */
    public boolean lSet(String key, List<object data-origwidth="" data-origheight="" style="width: 800px;"> value, long time) {
        try {
            redisTemplate.opsForList().rightPushAll(key, value);
            if (time > 0) {
                expire(key, time);
            }
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }
 
    /**
     * 根据索引修改list中的某条数据
     *
     * @param key   键
     * @param index 索引
     * @param value 值
     * @return
     */
    public boolean lUpdateIndex(String key, long index, Object value) {
        try {
            redisTemplate.opsForList().set(key, index, value);
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }
 
    /**
     * 移除N个值为value
     *
     * @param key   键
     * @param count 移除多少个
     * @param value 值
     * @return 移除的个数
     */
    public long lRemove(String key, long count, Object value) {
        try {
            Long remove = redisTemplate.opsForList().remove(key, count, value);
            return remove;
        } catch (Exception e) {
            e.printStackTrace();
            return 0;
        }
    }
 
 
    public void testAdd(Double X, Double Y, String accountId) {
        Long addedNum = redisTemplate.opsForGeo()
                .add("cityGeoKey", new Point(X, Y), accountId);
        System.out.println(addedNum);
    }
 
    public Long addGeoPoin() {
        Point point = new Point(123.05778991994906, 41.188314667658965);
        Long addedNum = redisTemplate.opsForGeo().geoAdd("cityGeoKey", point, 3);
        return addedNum;
    }
 
    public void testNearByPlace() {
        Distance distance = new Distance(100, Metrics.KILOMETERS);
        RedisGeoCommands.GeoRadiusCommandArgs args = RedisGeoCommands
                .GeoRadiusCommandArgs
                .newGeoRadiusArgs()
                .includeDistance()
                .includeCoordinates()
                .sortAscending()
                .limit(5);
        GeoResults> results = redisTemplate.opsForGeo()
                .radius("cityGeoKey", "北京", distance, args);
        System.out.println(results);
    }
 
    public GeoResults> testGeoNearByXY(Double X, Double Y) {
        Distance distance = new Distance(100, Metrics.KILOMETERS);
        Circle circle = new Circle(X, Y, Metrics.KILOMETERS.getMultiplier());
        RedisGeoCommands.GeoRadiusCommandArgs args = RedisGeoCommands
                .GeoRadiusCommandArgs
                .newGeoRadiusArgs()
                .includeDistance()
                .includeCoordinates()
                .sortAscending();
        GeoResults> results = redisTemplate.opsForGeo()
                .radius("cityGeoKey", circle, distance, args);
        System.err.println(results);
        return results;
    }
 
    /**
     * @Description: 执行lua脚本，只对key进行操作
     * @Param: [redisScript, keys]
     * @return: java.lang.Long
     * @Date: 2021/2/21 15:00
     */
    public Long executeLua(RedisScript redisScript, List keys) {
        return redisTemplate.execute(redisScript, keys);
    }
 
    /**
     * @Description: 执行lua脚本，只对key进行操作
     * @Param: [redisScript, keys, value]
     * @return: java.lang.Long
     * @Date: 2021/2/21 15:00
     */
    public Long executeLuaCustom(RedisScript redisScript, List keys, Object ...value) {
        return redisTemplate.execute(redisScript, keys, value);
    }
 
    /**
     * @Description: 执行lua脚本，只对key进行操作
     * @Param: [redisScript, keys, value]
     * @return: java.lang.Long
     * @Date: 2021/2/21 15:00
     */
    public Boolean executeBooleanLuaCustom(RedisScript redisScript, List keys, Object ...value) {
        return redisTemplate.execute(redisScript, keys, value);
    }
 
    /**
     * 时间窗口限流
     * @param key key
     * @param timeWindow 时间窗口
     * @return
     */
    public Integer rangeByScore(String key, Integer timeWindow) {
        // 获取当前时间戳
        Long currentTime = System.currentTimeMillis();
        Set<object data-origwidth="" data-origheight="" style="width: 800px;"> rangeSet = redisTemplate.opsForZSet().rangeByScore(key, currentTime - timeWindow, currentTime);
        if (ObjectUtil.isNotNull(rangeSet)) {
            return rangeSet.size();
        } else {
            return 0;
        }
    }
 
    /**
     * 新增Zset
     * @param key
     */
    public String addZset(String key) {
        String value = IdUtil.simpleUUID();
        Long currentTime = System.currentTimeMillis();
        redisTemplate.opsForZSet().add(key, value, currentTime);
        return value;
    }
 
    /**
     * 删除Zset
     * @param key
     */
    public void removeZset(String key, String value) {
        // 参数存在校验
        if (ObjectUtil.isNotNull(redisTemplate.opsForZSet().score(key, value))) {
            redisTemplate.opsForZSet().remove(key, value);
        }
    }
 
    /**
     * 通过前缀key值获取所有key内容(hash)
     * @param keyPrefix 前缀key
     * @param fieldArray 查询对象列信息
     */
    public List<object data-origwidth="" data-origheight="" style="width: 800px;"> getPrefixKeys(String keyPrefix, byte[][] fieldArray) {
        if (StrUtil.isBlank(keyPrefix)) {
            return null;
        }
        keyPrefix = keyPrefix.concat(FUZZY_ENQUIRY_KEY);
        // 所有完整key值
        Set keySet = redisTemplate.keys(keyPrefix);
        List<object data-origwidth="" data-origheight="" style="width: 800px;"> objectList = redisTemplate.executePipelined(new RedisCallback<object data-origwidth="" data-origheight="" style="width: 800px;">() {
            /**
             * Gets called by {@link RedisTemplate} with an active Redis connection. Does not need to care about activating or
             * closing the connection or handling exceptions.
             *
             * @param connection active Redis connection
             * @return a result object or {@code null} if none
             * @throws DataAccessException
             */
            @Override
            public Object doInRedis(RedisConnection connection) throws DataAccessException {
                for (String key : keySet) {
                    connection.hMGet(key.getBytes(StandardCharsets.UTF_8), fieldArray);
                }
                return null;
            }
        });
        return objectList;
    }
}
</object></object></object></object></object></object></object></object></object></object></object>

2.2 SimpleDistributeLock实现

具体锁以及解锁业务实现类，具体如下所示

package cn.git.common.lock;
 
import cn.git.common.exception.ServiceException;
import cn.git.redis.RedisUtil;
import cn.hutool.core.util.IdUtil;
import cn.hutool.core.util.ObjectUtil;
import cn.hutool.core.util.StrUtil;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.core.script.RedisScript;
import org.springframework.stereotype.Component;
 
import java.util.Collections;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
 
/**
 * 简单分布式锁
 * 可以实现锁的重入，锁自动延期
 * @program: bank-credit-sy
 * @author: lixuchun
 * @create: 2022-04-25
 */
@Slf4j
@Component
public class SimpleDistributeLock {
 
    /**
     * 活跃的锁集合
     */
    private volatile static CopyOnWriteArraySet ACTIVE_KEY_SET = new CopyOnWriteArraySet();
 
    /**
     * 定时线程池，续期使用
     */
    private static ScheduledExecutorService EXECUTOR_SERVICE = Executors.newScheduledThreadPool(5);
 
    /**
     * 解锁脚本, 脚本参数 KEYS[1]: 传入的key, ARGV[1]: 传入的value
     * // 如果没有key,直接返回1
     * if redis.call('EXISTS',KEYS[1]) == 0 then
     *  return 1
     * else
     *  // 如果key存在,并且value与传入的value相等,删除key,返回1，如果值不等,返回0
     *  if redis.call('GET',KEYS[1]) == ARGV[1] then
     *      return redis.call('DEL',KEYS[1])
     *  else
     *      return 0
     *  end
     * end
     */
    private static final String UNLOCK_SCRIPT = "if redis.call('EXISTS',KEYS[1]) == 0 then return 1 else if redis.call('GET',KEYS[1]) == ARGV[1] then return redis.call('DEL',KEYS[1]) else return 0 end end";
 
    /**
     * lua脚本参数介绍 KEYS[1]：传入的key  ARGV[1]：传入的value  ARGV[2]：传入的过期时间
     * // 如果成功设置keys，value值，然后设定过期时间，直接返回1
     * if redis.call('SETNX', KEYS[1], ARGV[1]) == 1 then
     *  redis.call('EXPIRE', KEYS[1], tonumber(ARGV[2]))
     *  return 1
     * else
     *  // 如果key存在，并且value值相等，则重置过期时间，直接返回1，值不等则返回0
     *  if redis.call('GET', KEYS[1]) == ARGV[1] then
     *      redis.call('EXPIRE', KEYS[1], tonumber(ARGV[2]))
     *      return 1
     *  else
     *      return 0
     *  end
     * end
     */
    private static final String REENTRANT_LOCK_LUA = "if redis.call('SETNX', KEYS[1], ARGV[1]) == 1 then redis.call('EXPIRE', KEYS[1], tonumber(ARGV[2])) return 1 else if redis.call('GET', KEYS[1]) == ARGV[1] then redis.call('EXPIRE', KEYS[1], tonumber(ARGV[2])) return 1 else return 0 end end";
 
    /**
     * 续期脚本
     * // 如果key存在，并且value值相等，则重置过期时间，直接返回1，值不等则返回0
     * if redis.call('EXISTS',KEYS[1]) == 1 and redis.call('GET',KEYS[1]) == ARGV[1] then
     *     redis.call('EXPIRE',KEYS[1],tonumber(ARGV[2]))
     *     return 1
     * else
     *     return 0
     * end
     */
    public static final String EXPIRE_LUA = "if redis.call('EXISTS',KEYS[1]) == 1 and redis.call('GET',KEYS[1]) == ARGV[1] then redis.call('EXPIRE',KEYS[1], tonumber(ARGV[2])) return 1 else return 0 end";
 
    /**
     * 释放锁失败标识
     */
    private static final long RELEASE_OK_FLAG = 0L;
 
    /**
     * 最大重试时间间隔,单位毫秒
     */
    private static final int MAX_RETRY_DELAY_MS = 2000;
 
    @Autowired
    private RedisUtil redisUtil;
 
    /**
     * 加锁方法
     * @param lockTypeEnum 锁信息
     * @param customKey 自定义锁定key
     * @return true 成功，false 失败
     */
    public String tryLock(LockTypeEnum lockTypeEnum, String customKey) {
        // 锁对应值信息
        String lockValue = IdUtil.simpleUUID();
        // 对自定义key进行加锁操作,value值与key值相同
        boolean result = redisUtil.setNxEx(lockTypeEnum.getLockType().concat(StrUtil.COLON).concat(customKey),
                lockValue,
                lockTypeEnum.getExpireTime().intValue());
        if (result) {
            log.info("[{}]加锁成功!", lockTypeEnum.getLockType().concat(StrUtil.COLON).concat(customKey));
            return lockValue;
        }
 
        return null;
    }
 
    /**
     * 进行加锁，加锁失败，再次进行加锁直到加锁成功
     * @param lockTypeEnum 分布式锁类型设定enum
     * @param customKey 自定义key
     * @return
     */
    public String tryContinueLock(LockTypeEnum lockTypeEnum, String customKey) {
        // 锁对应值信息
        String lockValue = IdUtil.simpleUUID();
 
        // 设置最大重试次数
        int maxRetries = 10;
        // 初始重试间隔，可调整
        int retryIntervalMs = 100;
 
        for (int attempt = 1; attempt  defaultRedisScript = new DefaultRedisScript();
        // Boolean 对应 lua脚本返回的0,1
        defaultRedisScript.setResultType(Boolean.class);
        // 设置重入锁脚本信息
        defaultRedisScript.setScriptText(REENTRANT_LOCK_LUA);
        // 进行重入锁执行
        Boolean executeResult = redisUtil.executeBooleanLuaCustom(defaultRedisScript,
                Collections.singletonList(lockKey),
                value,
                lockTypeEnum.getExpireTime().intValue());
        if (executeResult) {
            // 设置当前key为激活状态
            ACTIVE_KEY_SET.add(lockKey);
            // 设置定时任务，进行续期操作
            resetLockExpire(lockTypeEnum, customKey, value, lockTypeEnum.getExpireTime());
        }
        return executeResult;
    }
 
    /**
     * 进行续期操作
     * @param lockTypeEnum 锁定类型
     * @param customKey 自定义key
     * @param value 锁定值，一般为线程id或者uuid
     * @param expireTime 过期时间 单位秒，
     */
    public void resetLockExpire(LockTypeEnum lockTypeEnum, String customKey, String value, long expireTime) {
        // 续期的key信息
        String resetKey = lockTypeEnum.getLockType().concat(StrUtil.COLON).concat(customKey);
        // 校验当前key是否还在执行过程中
        if (!ACTIVE_KEY_SET.contains(resetKey)) {
            return;
        }
 
        // 时间设定延迟执行时间delay，默认续期时间是过期时间的1/3，在获取锁之后每expireTime/3时间进行一次续期操作
        long delay = expireTime  {
            log.info("自定义key[{}],对应值[{}]开始执行续期操作!", resetKey, value);
            // 执行续期操作，如果续期成功则再次添加续期任务，如果续期成功，进行下一次定时任务续期
            DefaultRedisScript defaultRedisScript = new DefaultRedisScript();
            // Boolean 对应 lua脚本返回的0,1
            defaultRedisScript.setResultType(Boolean.class);
            // 设置重入锁脚本信息
            defaultRedisScript.setScriptText(EXPIRE_LUA);
            // 进行重入锁执行
            boolean executeLua = redisUtil.executeBooleanLuaCustom(defaultRedisScript,
                    Collections.singletonList(resetKey),
                    value,
                    lockTypeEnum.getExpireTime().intValue());
 
            if (executeLua) {
                log.info("执行key[{}],value[{}]续期成功，进行下一次续期操作", resetKey, value);
                resetLockExpire(lockTypeEnum, customKey, value, expireTime);
            } else {
                // 续期失败处理，移除活跃key信息
                ACTIVE_KEY_SET.remove(resetKey);
            }
        }, delay, TimeUnit.SECONDS);
    }
 
    /**
     * 解锁操作
     * @param lockTypeEnum 锁定类型
     * @param customKey 自定义key
     * @param releaseValue 释放value
     * @return true 成功，false 失败
     */
    public boolean releaseLock(LockTypeEnum lockTypeEnum, String customKey, String releaseValue) {
        // 各个模块服务启动时间差，预留5秒等待时间，防止重调用
        if (ObjectUtil.isNotNull(lockTypeEnum.getLockedWaitTimeMiles())) {
            try {
                Thread.sleep(lockTypeEnum.getLockedWaitTimeMiles());
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
 
        // 设置释放锁定key,value值
        String releaseKey = lockTypeEnum.getLockType().concat(StrUtil.COLON).concat(customKey);
 
        // 释放锁定资源
        RedisScript longDefaultRedisScript = new DefaultRedisScript(UNLOCK_SCRIPT, Long.class);
        Long result = redisUtil.executeLuaCustom(longDefaultRedisScript,
                Collections.singletonList(releaseKey),
                releaseValue);
        // 根据返回结果判断是否成功成功匹配并删除 Redis 键值对，若果结果不为空和0，则验证通过
        if (ObjectUtil.isNotNull(result) && result != RELEASE_OK_FLAG) {
            // 当前key释放成功，从活跃生效keySet中移除
            ACTIVE_KEY_SET.remove(releaseKey);
            return true;
        }
        return false;
    }
 
}

注意，LUA脚本执行过程中有时候会有执行失败情况，这些情况下异常信息很难捕捉，所以可以在LUA脚本中设置日志打印，但是需要注意，需要配置redis配置文件，打开日志信息，此处以重入锁为例子，具体配置以及脚本信息如下：

1.redis配置日志级别，日志存储位置信息

# 日志级别，可以设置为 debug、verbose、notice、warning，默认为 notice
loglevel notice
 
# 日志文件路径
logfile "/path/to/redis-server.log"

2.配置LUA脚本信息

local function log(level, message)
    redis.log(level, "[DISTRIBUTED_LOCK]: " .. message)
end
 
if redis.call('SETNX', KEYS[1], ARGV[1]) == 1 then
    log(redis.LOG_NOTICE, "Successfully acquired lock with key: " .. KEYS[1])
    local expire_result = redis.call('EXPIRE', KEYS[1], tonumber(ARGV[2]))
    if expire_result == 1 then
        log(redis.LOG_NOTICE, "Set expiration of " .. ARGV[2] .. " seconds on lock.")
    else
        log(redis.LOG_WARNING, "Failed to set expiration on lock with key: " .. KEYS[1])
    end
    return 1
else
    local current_value = redis.call('GET', KEYS[1])
    if current_value == ARGV[1] then
        log(redis.LOG_NOTICE, "Lock already held by this client; renewing expiration.")
        local expire_result = redis.call('EXPIRE', KEYS[1], tonumber(ARGV[2]))
        if expire_result == 1 then
            log(redis.LOG_NOTICE, "Renewed expiration of " .. ARGV[2] .. " seconds on lock.")
        else
            log(redis.LOG_WARNING, "Failed to renew expiration on lock with key: " .. KEYS[1])
        end
        return 1
    else
        log(redis.LOG_DEBUG, "Lock is held by another client; not acquiring.")
        return 0
    end
end

2.3 锁枚举类实现

此处使用BASE_PRODUCT_TEST_LOCK作为测试的锁类型

package cn.git.common.lock;
 
import lombok.Getter;
 
/**
 * 分布式锁类型设定enum
 * @program: bank-credit-sy
 * @author: lixuchun
 * @create: 2022-04-25
 */
@Getter
public enum LockTypeEnum {
 
    /**
     * 分布式锁类型详情
     */
    DISTRIBUTE_TASK_LOCK("DISTRIBUTE_TASK_LOCK", 120L, "xxlJob初始化分布式锁", 5000L),
    CACHE_INIT_LOCK("CACHE_INIT_LOCK", 120L, "缓存平台初始化缓存信息分布式锁", 5000L),
    RULE_INIT_LOCK("RULE_INIT_LOCK", 120L, "规则引擎规则加载初始化", 5000L),
    SEQUENCE_LOCK("SEQUENCE_LOCK", 120L, "序列信息月末初始化!", 5000L),
    UAA_ONLINE_NUMBER_LOCK("UAA_ONLINE_LOCK", 20L, "登录模块刷新在线人数", 5000L),
    BASE_SERVER_IDEMPOTENCE("BASE_IDEMPOTENCE_LOCK", 15L, "基础业务幂等性校验"),
    WORK_FLOW_WEB_SERVICE_LOCK("WORK_FLOW_WEB_SERVICE_LOCK", 15L, "流程webService服务可用ip地址获取锁", 5000L),
    BASE_PRODUCT_TEST_LOCK("BASE_PRODUCT_TEST_LOCK", 10L, "产品测试分布式锁", null),
    ;
 
    /**
     * 锁类型
     */
    private String lockType;
 
    /**
     * 即过期时间,单位为second
     */
    private Long expireTime;
 
    /**
     * 枷锁成功后，默认等待时间，时间应小于过期时间，单位毫秒
     */
    private Long lockedWaitTimeMiles;
 
    /**
     * 描述信息
     */
    private String lockDesc;
 
    /**
     * 构造方法
     * @param lockType 类型
     * @param lockTime 锁定时间
     * @param lockDesc 锁描述
     */
    LockTypeEnum(String lockType, Long lockTime, String lockDesc) {
        this.lockDesc = lockDesc;
        this.expireTime = lockTime;
        this.lockType = lockType;
    }
 
    /**
     * 构造方法
     * @param lockType 类型
     * @param lockTime 锁定时间
     * @param lockDesc 锁描述
     * @param lockedWaitTimeMiles 锁失效时间
     */
    LockTypeEnum(String lockType, Long lockTime, String lockDesc, Long lockedWaitTimeMiles) {
        this.lockDesc = lockDesc;
        this.expireTime = lockTime;
        this.lockType = lockType;
        this.lockedWaitTimeMiles = lockedWaitTimeMiles;
    }
}

3. 测试

测试分为两部分，模拟多线程清库存产品，10个产品，1000个线程进行争夺，具体实现如下

3.1 测试代码部分

package cn.git.foreign;
 
import cn.git.api.client.EsbCommonClient;
import cn.git.api.dto.P043001009DTO;
import cn.git.common.lock.LockTypeEnum;
import cn.git.common.lock.SimpleDistributeLock;
import cn.git.foreign.dto.QueryCreditDTO;
import cn.git.foreign.manage.ForeignCreditCheckApiImpl;
import cn.hutool.core.util.IdUtil;
import cn.hutool.core.util.StrUtil;
import com.alibaba.fastjson.JSONObject;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
 
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
 
/**
 * @description: 分布式锁测试类
 * @program: bank-credit-sy
 * @author: lixuchun
 * @create: 2024-04-07 08:03:23
 */
@Slf4j
@RunWith(SpringRunner.class)
@SpringBootTest(classes = ForeignApplication.class)
public class DistributionLockTest {
 
    @Autowired
    private SimpleDistributeLock distributeLock;
 
    /**
     * 产品信息
     */
    private Product product = new Product("0001", 10, 0, "iphone");
 
    /**
     * @description: 产品信息
     * @program: bank-credit-sy
     * @author: lixuchun
     * @create: 2024-04-03
     */
    @Data
    @NoArgsConstructor
    @AllArgsConstructor
    public static class Product {
        /**
         * id
         */
        private String id;
 
        /**
         * 库存
         */
        private Integer stock;
 
        /**
         * 已售
         */
        private Integer sold;
 
        /**
         * 名称
         */
        private String name;
    }
 
    /**
     * 释放锁
     */
    @Test
    public void releaseLock() {
        distributeLock.releaseLock(LockTypeEnum.BASE_PRODUCT_TEST_LOCK, "0001", "xxxx");
    }
 
    /**
     * 分布式锁模拟测试
     */
    @Test
    public void testLock() throws InterruptedException {
        // 20核心线程，最大线程也是100，非核心线程空闲等待时间10秒，队列最大1000
        ThreadPoolExecutor executor = new ThreadPoolExecutor(100,
                100,
                10,
                TimeUnit.SECONDS,
                new LinkedBlockingQueue(10000));
 
        // 模拟1000个请求
        CountDownLatch countDownLatch = new CountDownLatch(1000);
 
        // 模拟10000个人抢10个商品
        for (int i = 0; i  {
                // 加锁
                // soldByLock();
                // 不加锁扣减库存
                normalSold();
                countDownLatch.countDown();
            });
        }
        countDownLatch.await();
        executor.shutdown();
 
        // 输出产品信息
        System.out.println(JSONObject.toJSONString(product));
    }
 
    /**
     * 加锁减库存
     */
    public void soldByLock() {
        // 设置加锁value信息
        String lockValue = IdUtil.simpleUUID();
        try {
            boolean isLocked = distributeLock.tryReentrantLock(LockTypeEnum.BASE_PRODUCT_TEST_LOCK, lockValue, product.getId());
            if (isLocked) {
                // 加锁成功，开始减库存信息
                if (product.getStock() > 0) {
                    product.setStock(product.getStock() - 1);
                    product.setSold(product.getSold() + 1);
                    System.out.println(StrUtil.format("减库存成功，剩余库存[{}]", product.getStock()));
                } else {
                    System.out.println("库存不足");
                }
            }
            // 暂停1000毫秒，模拟业务处理
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            distributeLock.releaseLock(LockTypeEnum.BASE_PRODUCT_TEST_LOCK, product.getId(), lockValue);
        }
    }
 
    /**
     * 不加锁减库存
     */
    public void normalSold() {
        // 获取线程id
        long id = Thread.currentThread().getId();
        // 暂停1000毫秒，模拟业务处理
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
        // 开始库存计算
        if (product.getStock() > 0) {
            product.setStock(product.getStock() - 1);
            product.setSold(product.getSold() + 1);
            System.out.println(StrUtil.format("线程[{}]减库存成功，剩余库存[{}]", id, product.getStock()));
        } else {
            System.out.println("库存不足");
        }
    }
}

3.2 无锁库存处理情况

无锁情况下，发生产品超发情况，卖出11个产品，具体如下图

3.3 加锁处理情况

多次实验，没有发生产品超发情况，具体测试结果如下：

4. 其他实现

还可以使用Redisson客户端进行分布式锁实现，这样更加简单安全，其有自己的看门狗机制，续期加锁解锁都更加方便，简单操作过程实例代码如下

import org.redisson.Redisson;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.redisson.config.Config;
  
import java.util.concurrent.TimeUnit;
  
/**
 * @description: Redisson客户端实现
 * @program: bank-credit-sy
 * @author: lixuchun
 * @create: 2022-07-12 09:03:23
 */
public class RedissonLockExample {
    public static void main(String[] args) {
        // 配置Redisson客户端
        Config config = new Config();
        config.useSingleServer().setAddress("redis://localhost:6379");
        RedissonClient redisson = Redisson.create(config);
  
        // 获取锁对象
        RLock lock = redisson.getLock("myLock");
        try {
            // 尝试获取锁，最多等待100秒，锁定之后10秒自动释放
            // 锁定之后会自动续期10秒
            if (lock.tryLock(100, 10, TimeUnit.SECONDS)) {
                try {
                    // 处理业务逻辑
                } finally {
                    // 释放锁
                    lock.unlock();
                }
            }
        } catch (InterruptedException e) {
            // 处理中断异常
            Thread.currentThread().interrupt();
        } finally {
            // 关闭Redisson客户端
            redisson.shutdown();
        }
    }
}

其中锁定api是否开启看门狗，整理如下

// 开始拿锁，失败阻塞重试
RLock lock = redissonClient.getLock("guodong");
// 具有Watch Dog 自动延期机制 默认续30s 每隔30/3=10 秒续到30s
lock.lock();
// 尝试拿锁10s后停止重试,返回false 具有Watch Dog 自动延期机制 默认续30s
boolean res1 = lock.tryLock(10, TimeUnit.SECONDS); 
 
// 尝试拿锁10s后，没有Watch Dog
lock.lock(10, TimeUnit.SECONDS);
// 没有Watch Dog ，10s后自动释放
lock.lock(10, TimeUnit.SECONDS);
// 尝试拿锁100s后停止重试,返回false 没有Watch Dog ，10s后自动释放
boolean res2 = lock.tryLock(100, 10, TimeUnit.SECONDS);

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redis分布式锁实现示例

目录

1.需求

2.具体实现

2.1 redis基本操作工具类redisUtil

2.2 SimpleDistributeLock实现

2.3 锁枚举类实现

3. 测试

3.1 测试代码部分

3.2 无锁库存处理情况

3.3 加锁处理情况

4. 其他实现

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目录

1.需求

2.具体实现

2.1 redis基本操作工具类redisUtil

2.2 SimpleDistributeLock实现

2.3 锁枚举类实现

3. 测试

3.1 测试代码部分

3.2 无锁库存处理情况

3.3 加锁处理情况

4. 其他实现

微信扫一扫：分享

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