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Redis实现分布式锁
/** * @author http://blog.csdn.net/java2000_wl * @version <b>1.0.0</b> */ public class RedisBillLockHandler implements IBatchBillLockHandler { private static final Logger LOGGER = LoggerFactory.getLogger(RedisBillLockHandler.class); private static final int DEFAULT_SINGLE_EXPIRE_TIME = 3; private static final int DEFAULT_BATCH_EXPIRE_TIME = 6; private final JedisPool jedisPool; /** * 构造 * @author http://blog.csdn.net/java2000_wl */ public RedisBillLockHandler(JedisPool jedisPool) { this.jedisPool = jedisPool; } /** * 获取锁 如果锁可用 立即返回true, 否则返回false * @author http://blog.csdn.net/java2000_wl * @param billIdentify * @return */ public boolean tryLock(IBillIdentify billIdentify) { return tryLock(billIdentify, 0L, null); } /** * 锁在给定的等待时间内空闲,则获取锁成功 返回true, 否则返回false * @author http://blog.csdn.net/java2000_wl * @param billIdentify * @param timeout * @param unit * @return */ public boolean tryLock(IBillIdentify billIdentify, long timeout, TimeUnit unit) { String key = (String) billIdentify.uniqueIdentify(); Jedis jedis = null; try { jedis = getResource(); long nano = System.nanoTime(); do { LOGGER.debug("try lock key: " + key); Long i = jedis.setnx(key, key); //只有不存在的时候才设置 if (i == 1) { jedis.expire(key, DEFAULT_SINGLE_EXPIRE_TIME); LOGGER.debug("get lock, key: " + key + " , expire in " + DEFAULT_SINGLE_EXPIRE_TIME + " seconds."); return Boolean.TRUE; } else { // 存在锁 if (LOGGER.isDebugEnabled()) { String desc = jedis.get(key); LOGGER.debug("key: " + key + " locked by another business:" + desc); } } if (timeout == 0) { break; } Thread.sleep(300); } while ((System.nanoTime() - nano) < unit.toNanos(timeout)); return Boolean.FALSE; } catch (JedisConnectionException je) { LOGGER.error(je.getMessage(), je); returnBrokenResource(jedis); } catch (Exception e) { LOGGER.error(e.getMessage(), e); } finally { returnResource(jedis); } return Boolean.FALSE; } /** * 如果锁空闲立即返回 获取失败 一直等待 * @author http://blog.csdn.net/java2000_wl * @param billIdentify */ public void lock(IBillIdentify billIdentify) { String key = (String) billIdentify.uniqueIdentify(); Jedis jedis = null; try { jedis = getResource(); do { LOGGER.debug("lock key: " + key); Long i = jedis.setnx(key, key); if (i == 1) { jedis.expire(key, DEFAULT_SINGLE_EXPIRE_TIME); LOGGER.debug("get lock, key: " + key + " , expire in " + DEFAULT_SINGLE_EXPIRE_TIME + " seconds."); return; } else { if (LOGGER.isDebugEnabled()) { String desc = jedis.get(key); LOGGER.debug("key: " + key + " locked by another business:" + desc); } } Thread.sleep(300); } while (true); } catch (JedisConnectionException je) { LOGGER.error(je.getMessage(), je); returnBrokenResource(jedis); } catch (Exception e) { LOGGER.error(e.getMessage(), e); } finally { returnResource(jedis); } } /** * 释放锁 * @author http://blog.csdn.net/java2000_wl * @param billIdentify */ public void unLock(IBillIdentify billIdentify) { List<IBillIdentify> list = new ArrayList<IBillIdentify>(); list.add(billIdentify); unLock(list); } /** * 批量获取锁 如果全部获取 立即返回true, 部分获取失败 返回false * @author http://blog.csdn.net/java2000_wl * @date 2013-7-22 下午10:27:44 * @param billIdentifyList * @return */ public boolean tryLock(List<IBillIdentify> billIdentifyList) { return tryLock(billIdentifyList, 0L, null); } /** * 锁在给定的等待时间内空闲,则获取锁成功 返回true, 否则返回false * @author http://blog.csdn.net/java2000_wl * @param billIdentifyList * @param timeout * @param unit * @return */ public boolean tryLock(List<IBillIdentify> billIdentifyList, long timeout, TimeUnit unit) { Jedis jedis = null; try { List<String> needLocking = new CopyOnWriteArrayList<String>(); List<String> locked = new CopyOnWriteArrayList<String>(); jedis = getResource(); long nano = System.nanoTime(); do { // 构建pipeline,批量提交 Pipeline pipeline = jedis.pipelined(); for (IBillIdentify identify : billIdentifyList) { String key = (String) identify.uniqueIdentify(); needLocking.add(key); pipeline.setnx(key, key); } LOGGER.debug("try lock keys: " + needLocking); // 提交redis执行计数 List<Object> results = pipeline.syncAndReturnAll(); for (int i = 0; i < results.size(); ++i) { Long result = (Long) results.get(i); String key = needLocking.get(i); if (result == 1) { // setnx成功,获得锁 jedis.expire(key, DEFAULT_BATCH_EXPIRE_TIME); locked.add(key); } } needLocking.removeAll(locked); // 已锁定资源去除 if (CollectionUtils.isEmpty(needLocking)) { return true; } else { // 部分资源未能锁住 LOGGER.debug("keys: " + needLocking + " locked by another business:"); } if (timeout == 0) { break; } Thread.sleep(500); } while ((System.nanoTime() - nano) < unit.toNanos(timeout)); // 得不到锁,释放锁定的部分对象,并返回失败 if (!CollectionUtils.isEmpty(locked)) { jedis.del(locked.toArray(new String[0])); } return false; } catch (JedisConnectionException je) { LOGGER.error(je.getMessage(), je); returnBrokenResource(jedis); } catch (Exception e) { LOGGER.error(e.getMessage(), e); } finally { returnResource(jedis); } return true; } /** * 批量释放锁 * @author http://blog.csdn.net/java2000_wl * @param billIdentifyList */ public void unLock(List<IBillIdentify> billIdentifyList) { List<String> keys = new CopyOnWriteArrayList<String>(); for (IBillIdentify identify : billIdentifyList) { String key = (String) identify.uniqueIdentify(); keys.add(key); } Jedis jedis = null; try { jedis = getResource(); jedis.del(keys.toArray(new String[0])); LOGGER.debug("release lock, keys :" + keys); } catch (JedisConnectionException je) { LOGGER.error(je.getMessage(), je); returnBrokenResource(jedis); } catch (Exception e) { LOGGER.error(e.getMessage(), e); } finally { returnResource(jedis); } } /** * @author http://blog.csdn.net/java2000_wl * @date 2013-7-22 下午9:33:45 * @return */ private Jedis getResource() { return jedisPool.getResource(); } /** * 销毁连接 * @author http://blog.csdn.net/java2000_wl * @param jedis */ private void returnBrokenResource(Jedis jedis) { if (jedis == null) { return; } try { //容错 jedisPool.returnBrokenResource(jedis); } catch (Exception e) { LOGGER.error(e.getMessage(), e); } } /** * @author http://blog.csdn.net/java2000_wl * @param jedis */ private void returnResource(Jedis jedis) { if (jedis == null) { return; } try { jedisPool.returnResource(jedis); } catch (Exception e) { LOGGER.error(e.getMessage(), e); } }
Redis实现分布式锁
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