listener
http://www.cnblogs.com/xdp-gacl/p/3969249.html
http://blog.csdn.net/java_pengjin/article/details/6760175
Filter、Servlet、Listener
http://blog.csdn.net/agileclipse/article/details/9014683
Filter、Servlet、Listener执行顺序
http://blog.csdn.net/wocaonima123987/article/details/8620460