【转载】几篇关于单例模式的讲解
http://www.ibm.com/developerworks/cn/java/l-singleton/
http://jiangzhengjun.iteye.com/blog/657983
http://jiangzhengjun.iteye.com/blog/652440
http://www.iteye.com/topic/260515
http://www.iteye.com/topic/157952
http://www.iteye.com/topic/218645
http://www.iteye.com/topic/909092
http://www.iteye.com/topic/875420
http://www.iteye.com/topic/684052
http://www.iteye.com/topic/1121678
http://freish.iteye.com/blog/1008304
http://www.iteye.com/topic/667865
http://www.iteye.com/topic/897652
http://www.iteye.com/topic/691223
