随笔Java 基于Redis分布式锁

Posted 2022-12-06 醇氧

定义接口

public interface IDistributedLock 
    boolean tryLock(String var1, Object var2);

    boolean tryLock(String var1, Object var2, int var3);

    boolean unLock(String var1, Object var2);

实现类

public class DistributedLockImpl 
    
    private static final String lockScript = "local n = redis.call('setnx',KEYS[1],ARGV[1])\\nif n == 1 then redis.call('expire',KEYS[1],ARGV[2]) end\\nreturn n";
    @Autowired
    private RedisTemplate template;
   
    private int defaultExpireTime = 3;

    public DistributedLockImpl() 
    

    public boolean tryLock(String busiType, Object key) 
        return this.tryLock(busiType, key, this.defaultExpireTime);
    

    public boolean tryLock(String busiType, Object key, int expire) 
        return (Boolean)this.template.execute((jedis) -> 
            String lockKey = this.getLockKey(busiType, key);
            String lockValue = this.getLockValue(busiType, key);
            boolean locked = (Long)jedis.eval("local n = redis.call('setnx',KEYS[1],ARGV[1])\\nif n == 1 then redis.call('expire',KEYS[1],ARGV[2]) end\\nreturn n", 1, new String[]lockKey, lockValue, String.valueOf(expire)) > 0L;
          
            return locked;
        );
    

    public boolean unLock(String busiType, Object key) 
        return (Boolean)this.template.execute((jedis) -> 
            String lockedKey = this.getLockKey(busiType, key);
                if (jedis.del(lockedKey) > 0L) 
                    return true;
                 else 
                    return false;
                
        );
    

    private String getLockKey(String busiType, Object key) 
        Objects.requireNonNull(busiType);
        Objects.requireNonNull(key);
        return busiType + "_" + key;
    

    private String getLockValue(String busiType, Object key) 
        Objects.requireNonNull(busiType);
        Objects.requireNonNull(key);
        return "lock_" + busiType + "_" + key + "_" + (new SecureRandom()).nextInt();