http://www.cnblogs.com/waterystone/p/4920797.html
http://www.infoq.com/cn/articles/jdk1.8-abstractqueuedsynchronizer#anch140433
http://www.infoq.com/cn/articles/java8-abstractqueuedsynchronizer
Java并发之AQS详解
原文：http://www.cnblogs.com/chengdabelief/p/7498938.html
