redis分布式锁

//这个没有重新获取机制，加锁的时候需要 自己在外面while循环 尝试获取锁
@Component
public class RedisLockUtil {
    private  static  final  String REDIS_SUCCESS="OK";
    private  static  final  String REDIS_NX="NX";
    private  static  final  String REDIS_PX="PX";
     private  static  final  String REDIS_SCRIPT="if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";
    @Autowired
    private JedisPool jedisPool;

    public RedisLockUtil() {
    }
    public RedisLockUtil(JedisPool jedisPool) {
        this.jedisPool = jedisPool;
    }
    /**
     *
     * @param key   锁名
     * @param value 锁唯一占用标示
     * @param loseTime  锁失效时间,根据程序设定
     * @return
     */
    public ReturnBean addLock(String key, String value,Long loseTime){
        ReturnBean returnBean = new ReturnBean();
        try {
            if(StringUtil.isEmpty(key) || StringUtil.isEmpty(value)){
                throw new BusinessException("key和value值不能为空");
            }
            Jedis jedis = jedisPool.getResource();
            String res = jedis.set(key, value, REDIS_NX, REDIS_PX, loseTime);
            jedis.close();
            if(REDIS_SUCCESS.equals(res)){
                returnBean.setCode(CommonMsg.SUCCESSCODE);
            }else{
                returnBean.setCode(CommonMsg.ERRORCODE);
                returnBean.setMsg(key+":锁被占用");
            }
        } catch (Exception e) {
            returnBean.setCode(CommonMsg.ERRORCODE);
            if(e instanceof BusinessException){
                returnBean.setMsg(e.getMessage());
            }else{
                returnBean.setMsg("jedis连接异常");
            }
            e.printStackTrace();
        }
        return returnBean;
    }
    /**
     * 释放锁
     * @param key
     * @param value
     * @return
     */
    public ReturnBean delLock(String key,String value){
        ReturnBean returnBean = new ReturnBean();
        try {
            if(StringUtil.isEmpty(key) || StringUtil.isEmpty(value)){
                throw new BusinessException("key和value值不能为空");
            }
            Jedis jedis = jedisPool.getResource();
            List<String> keyList = new ArrayList<>();
            keyList.add(key);
            List<String> argvList = new ArrayList<>();
            argvList.add(value);
            Long result = (Long) jedis.eval(REDIS_SCRIPT, keyList, argvList);
            jedis.close();
            if(1 != result){
                returnBean.setCode(CommonMsg.ERRORCODE);
                returnBean.setMsg(key+":锁释放失败");
            }else{
                returnBean.setCode(CommonMsg.SUCCESSCODE);
            }
        } catch (BusinessException e) {
            returnBean.setCode(CommonMsg.ERRORCODE);
            if(e instanceof BusinessException){
                returnBean.setMsg(e.getMessage());
            }else{
                returnBean.setMsg("jedis连接异常");
            }
            e.printStackTrace();
        }
        return returnBean;
    }
}

使用：

public String redisLockTest(){
        String uuid = UUID.randomUUID().toString();
        ReturnBean returnBean = redisLockUtil.addLock(this.getClass().getName(), uuid, 1000 * 60L);
        if(CommonMsg.SUCCESSCODE.equals(returnBean.getCode())){
            System.out.println("获取锁完成......");
            ReturnBean rb = redisLockUtil.delLock(this.getClass().getName(), uuid);

            if(CommonMsg.SUCCESSCODE.equals(rb.getCode())){
                System.out.println("释放锁完成.......");
            }
        }
        return "0000";
    }

  redisTemplate方式：

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisCluster;
import redis.clients.jedis.JedisCommands;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.List;

/**
 * @param
 * @author 王晓磊
 * @Description: redis分布式锁
 * @return
 * @throws
 * @date 2019-4-12 16:12
 */
@Component
public class RedisLockUtil {
    @Autowired
    private StringRedisTemplate redisTemplate;

    public static final String UNLOCK_LUA;

    static {
        StringBuilder sb = new StringBuilder();
        sb.append("if redis.call("get",KEYS[1]) == ARGV[1] ");
        sb.append("then ");
        sb.append("    return redis.call("del",KEYS[1]) ");
        sb.append("else ");
        sb.append("    return 0 ");
        sb.append("end ");
        UNLOCK_LUA = sb.toString();
    }

    private final Logger logger = LoggerFactory.getLogger(RedisLockUtil.class);


    //trytime是指当锁被其他进程用时，尝试获取时间，如果为-1则表示一直尝试获取。expire是指获取锁之后，锁的超时时间
    public boolean lock(String key, String value, Long trytime, Long expire) {
        if (trytime == null) trytime = 1000L*60*60;  //获取时间默认1小时
        if (expire == null || expire < 0 ) expire = 10000L;
        long endTime = System.currentTimeMillis() + trytime;

        if (trytime == -1) {  //一直获取锁，知道获取为止
            while (true) {
                if (addLock(key, value, trytime, expire)) {
                    return true;
                }
            }
        } else {
            while (System.currentTimeMillis() <= endTime) {
                if (addLock(key, value, trytime, expire)) {
                    return true;
                }
            }
        }
        return false;
    }

    public boolean unlock(String key, String requestId) {
        return delLock(key, requestId);
    }


    private boolean addLock(String key, String value, long trytime, long expire) {
        try {
            RedisCallback<String> callback = (connection) -> {
                JedisCommands commands = (JedisCommands) connection.getNativeConnection();
                return commands.set(key, value, "NX", "PX", expire);
            };
            String result = redisTemplate.execute(callback);
            return !StringUtils.isEmpty(result);
        } catch (Exception e) {
            logger.error("set redis occured an exception", e);
        }
        return false;
    }


    private boolean delLock(String key, String requestId) {
        // 释放锁的时候，有可能因为持锁之后方法执行时间大于锁的有效期，此时有可能已经被另外一个线程持有锁，所以不能直接删除
        try {
            List<String> keys = new ArrayList<>();
            keys.add(key);
            List<String> args = new ArrayList<>();
            args.add(requestId);

            // 使用lua脚本删除redis中匹配value的key，可以避免由于方法执行时间过长而redis锁自动过期失效的时候误删其他线程的锁
            // spring自带的执行脚本方法中，集群模式直接抛出不支持执行脚本的异常，所以只能拿到原redis的connection来执行脚本
            RedisCallback<Long> callback = (connection) -> {
                Object nativeConnection = connection.getNativeConnection();
                // 集群模式和单机模式虽然执行脚本的方法一样，但是没有共同的接口，所以只能分开执行
                // 集群模式
                if (nativeConnection instanceof JedisCluster) {
//                    logger.info("集群模式");
                    return (Long) ((JedisCluster) nativeConnection).eval(UNLOCK_LUA, keys, args);
                }

                // 单机模式
                else if (nativeConnection instanceof Jedis) {
//                    logger.info("单机模式");
                    return (Long) ((Jedis) nativeConnection).eval(UNLOCK_LUA, keys, args);
                }
                return 0L;
            };
            Long result = redisTemplate.execute(callback);
            return result != null && result > 0;
        } catch (Exception e) {
            logger.error("release lock occured an exception", e);
        } finally {
            // 清除数据
        }
        return false;
    }

}