http://www.importnew.com/15731.html
http://www.cnblogs.com/yezhenhan/archive/2012/01/07/2315652.html
http://www.cnblogs.com/dolphin0520/p/3920397.html
http://www.cnblogs.com/felixzh/p/6036074.html
http://www.cnblogs.com/whgw/archive/2011/09/28/2194760.html
http://www.cnblogs.com/dolphin0520/p/3949310.html
http://blog.csdn.net/zhangzhaokun/article/details/6615454
http://blog.csdn.net/fhd001/article/details/6775439
http://ifeve.com/concurrency-semaphore/#more-14753
http://www.cnblogs.com/riskyer/p/3263032.html
线程池：
http://www.oschina.net/question/565065_86540
http://www.cnblogs.com/dolphin0520/p/3932921.html
http://www.open-open.com/solution/view/1320545914983