利用redis的transaction功能，实现分布式下加锁
package memcached;import java.util.List;import redis.clients.jedis.Jedis;import redis.clients.jedis.Transaction;public class TestJedisLock {Jedis jedis = new Jedis("127.0.0.1", 6379);public static void main(String[] args) {TestJedisLock t = new TestJedisLock();System.out.println(t.testLock());}public boolean testLock() {String pk = "mypk";String lockPk = "lock" + pk; String lockValue = String.valueOf(System.currentTimeMillis()) + "111"; try { if(jedis.exists(lockPk)) { // other one locked already System.out.println("Already locked pk:" + pk); return false; } jedis.watch(lockPk);// make sure below operation is particle jedis.multi(); Transaction trans = new Transaction(jedis.getClient()); trans.set(lockPk, lockValue); trans.expire(lockPk, 60*60); List<Object> ret = trans.exec(); if(ret == null) { System.out.println("Concurrent lock fail for pk:" + pk); return false; } String lockedValue = jedis.get(lockPk); return lockValue.equals(lockedValue); // locked success } catch (Exception e) { System.out.println("Exception in lock for pk:" + pk); return false; }}}?