新建

李林

2023-10-07 658d4927d468c47208fd012d9128b09249c07eff

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package com.chinaztt.mes.warehouse.util;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
 
import java.util.Objects;
 
/**
 * @Author: Zero
 * @Date: 2022/9/16 14:43
 * @Description:
 */
@Component
public class RedisLockHelper {
 
    @Autowired
    private RedisTemplate redisTemplate;
 
    public static final String LOCK_PREFIX = "redis_reverse_lock";
    public static final int LOCK_EXPIRE = 5000;
 
    public Boolean lock(String key) {
        String lock = LOCK_PREFIX + key;
        return (Boolean) redisTemplate.execute((RedisCallback) connection -> {
            long expireAt = System.currentTimeMillis() + LOCK_EXPIRE + 1;
            Boolean acquire = connection.setNX(lock.getBytes(), String.valueOf(expireAt).getBytes());
            if (acquire) {
                return Boolean.TRUE;
            } else {
                byte[] value = connection.get(lock.getBytes());
                if (Objects.nonNull(value) && value.length > 0) {
                    long expireTime = Long.parseLong(new String(value));
                    // 如果锁已经过期
                    if (expireTime < System.currentTimeMillis()) {
                        // 重新加锁，防止死锁
                        byte[] oldValue = connection.getSet(lock.getBytes(),
                                String.valueOf(System.currentTimeMillis() + LOCK_EXPIRE + 1).getBytes());
                        return Long.parseLong(new String(oldValue)) < System.currentTimeMillis();
                    }
                }
            }
            return Boolean.FALSE;
        });
    }
 
    public void delLock(String key) {
        redisTemplate.execute((RedisCallback) redisConnection -> {
            redisConnection.del((LOCK_PREFIX + key).getBytes());
            return null;
        });
    }
 
}