servletContext

相同：其实servletContext和application 是一样的，就相当于一个类创建了两个不同名称的变量。在

<wbr></wbr>

<wbr><wbr><wbr><wbr><wbr>servlet中ServletContext就是application对象。大家只要打开jsp编译过后生成的Servlet中的</wbr></wbr></wbr></wbr></wbr>

<wbr><wbr><wbr><wbr><wbr>_jspService()方法就可以看到如下的声明：<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>ServletContext application = null;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>application = pageContext.getServletContext();<wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

不同：两者的区别就是application用在jsp中，servletContext用在servlet中。application和page<wbr><wbr></wbr></wbr>

<wbr><wbr><wbr><wbr><wbr><wbr>request session 都是JSP中的内置对象，在后台用ServletContext存储的属性数据可以用<wbr><wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><wbr><wbr><wbr><wbr>application对象获得。<br><wbr><wbr><wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

而且application的作用域是整个Tomcat启动的过程。
例如: ServletContext.setAttribute("username",username);
则在JSP网页中可以使用<wbr>application.getAttribute("username");<br> 来得到这个用户名。</wbr>