redis的分布式锁工具LockUtil

/**
 * 基于redis的分布式锁工具
 * 
 * @author yuyufeng
 *
 */
public class LockUtil {
 
	// 获取redis
	static JedisPool jedisPool;
	static {
		JedisPoolConfig config = new JedisPoolConfig();
		config.setMaxTotal(100);
		config.setMaxIdle(5);
		config.setMaxWaitMillis(1000);
		config.setTestOnBorrow(false);
 
		// 构造池
		jedisPool = new JedisPool(config, "127.0.0.1", 6379, 1000, "12345");
	}
 
	// redis键值前缀标识
	private final static String PREFIX = "LOCK-FLAG-";
	// 默认获取锁的等待时间
	private final static Integer WAITTIME = 200;
 
	/**
	 * 获取锁
	 * 
	 * @param uid：锁的唯一标识
	 * @param expire：锁自动释放时间
	 * @return true：获得锁；false:锁已被占用
	 */
	public static Boolean getLock(String uid, Integer expire) {
		if (expire < 0) {
            return false;
        }
		Long beginTime = System.currentTimeMillis();
		do {
			Jedis jedis = jedisPool.getResource();
			
			//防止程序出错设置键值不失效
			if(jedis.ttl(PREFIX + uid) == -1){
				jedis.expire(PREFIX + uid, expire);
			}
			
			Long res = jedis.incr(PREFIX + uid);
			
			
			
			if (res == 1) {
				jedis.expire(PREFIX + uid, expire);
 
				if (jedis != null) {
					try {
						jedis.close();
					} catch (Exception e1) {
						e1.printStackTrace();
					}
				}
 
				return true;
			}
 
			if (jedis != null) {
				try {
					jedis.close();
				} catch (Exception e1) {
					e1.printStackTrace();
				}
			}
 
			try {
				Thread.sleep(100);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.print(".");
		} while ((System.currentTimeMillis() - beginTime) < WAITTIME);
 
		return false;
	}
 
	/**
	 * 获取锁
	 * 
	 * @param uid：锁的唯一标识
	 * @param expire：锁自动释放时间
	 * @param timeout：超时等待时间
	 * @return true：获得锁；false:锁已被占用
	 */
	public static Boolean getLock(String uid, Integer expire, Integer timeout) {
		if (expire < 0) {
            return false;
        }
		Long beginTime = System.currentTimeMillis();
		do {
			Jedis jedis = jedisPool.getResource();
			
			//防止程序出错设置键值不失效
			if(jedis.ttl(PREFIX + uid) == -1){
				jedis.expire(PREFIX + uid, expire);
			}
			
			Long res = jedis.incr(PREFIX + uid);
			
			
			
			if (res == 1) {
				jedis.expire(PREFIX + uid, expire);
 
				if (jedis != null) {
					try {
						jedis.close();
					} catch (Exception e1) {
						e1.printStackTrace();
					}
				}
 
				return true;
			}
 
			if (jedis != null) {
				try {
					jedis.close();
				} catch (Exception e1) {
					e1.printStackTrace();
				}
			}
 
			try {
				Thread.sleep(100);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.print(".");
		} while ((System.currentTimeMillis() - beginTime) < timeout);
 
		return false;
	}
 
	/**
	 * 手动释放锁
	 * 
	 * @param uid：锁的唯一标识
	 */
	public static void returnLock(String uid) {
		Jedis jedis = jedisPool.getResource();
		jedis.del(PREFIX + uid);
		if (jedis != null) {
			try {
				jedis.close();
			} catch (Exception e1) {
				e1.printStackTrace();
			}
		}
		System.out.println("手动释放锁：" + uid);
	}
 
}

　　

	/**
	 * 测试
	 * 
	 * @param args
	 */
	public static void main(String[] args) {
 
		AtomicInteger ai = new AtomicInteger(1);
		AtomicInteger count = new AtomicInteger(0);
		for (int i = 0; i < 30; i++) {
			new Thread() {
				@Override
				public void run() {
					String uid = "a" + ai.incrementAndGet() % 10; // 获取锁，并设置10秒失效
					Boolean lock = LockUtil.getLock(uid, 10);
					System.out.println(uid + "取锁结果：" + lock);
					if (lock) {
						// dosomething..
						 count.incrementAndGet();
					}
					System.out.println("当前获取锁的数量："+count);
				}
			}.start();
		}
 
		// 手动解锁测试,超时测试
		//Boolean lock = LockUtil.getLock("testReturnKey", 1);
		//System.out.println("testReturnKey" + "取锁结果：" + lock);
		// LockUtil.returnLock("testReturnKey");
 
	}

　　

转载于:https://www.cnblogs.com/dinghaoran/p/11202454.html