JavaWeb编程精髓随书代码，第5章到第8章内容。-With the essence of the book JavaWeb programming code, in Chapter 5 to Chapter 8 content.

《Java Web整合开发王者归来（刘京华 著）》漏掉的源代码 第二部分-" Java Web Integrated Development Return of the King (Liu Jinghua with)" the second part of the source code missing

1. 了解在哪些对象上可以产生事件； 2. 掌握ServletContext和HttpSession对象上的事件处理方法。 3. 了解在ServletRequest对象上的事件及处理方法。(1. understand which events can be generated on objects; 2. mastering event handling methods on ServletContext and HttpSess