redis 分布式锁 Java实现

相关链接

• 基于Redis的分布式锁实现 - 掘金 (juejin.cn)
• Redis——由分布式锁造成的重大事故 - 掘金 (juejin.cn)
• Redisson实现Redis分布式锁的N种姿势 (qq.com)
• Redlock：Redis分布式锁最牛逼的实现 (qq.com)

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

/**
 * redis 分布式锁
 * 只适用于单机模式 TODO 集群架构下可能无法保证高可用
 *
 * @author lingzilong
 * @date 2022/9/30
 * @since 1.0
 */
public class RedisLockService {

    private static final Logger log = LoggerFactory.getLogger(RedisLockService.class);

    private StringRedisTemplate redisTemplate;

    public RedisLockService(StringRedisTemplate redisTemplate) {
        this.redisTemplate = redisTemplate;
    }

    public boolean lock(String key, String value, int timeout) {
        log.info("redis lock key [{}], value is [{}]", key, value);
        try {
            return Boolean.TRUE.equals(redisTemplate.opsForValue().setIfAbsent(key, value, timeout, TimeUnit.SECONDS));
        } catch (Exception e) {
            log.error("redis lock fail.", e);
            return false;
        }
    }

    public void unlock(String key, String value) {
        log.info("redis unlock key [{}], value is [{}]", key, value);
        try {
            DefaultRedisScript<Long> redisScript = new DefaultRedisScript<>();
            redisScript.setResultType(Long.class);
            redisScript.setScriptText("if redis.call('get',KEYS[1]) == ARGV[1] then return redis.call('del',KEYS[1]) else return 0 end");
            Long result = redisTemplate.execute(redisScript, Collections.singletonList(key), value);
            log.info("redis unlock result [{}].", result);
        } catch (Exception e) {
            log.error("redis unlock fail.", e);
        }
    }
}