早期用servlet充当视图层,业务逻辑层及持久层.
[code]
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String aa = config.getInitParameter("aa");
String bb = config.getServletContext().getInitParameter("bb");
String kk = config.getServletContext().getInitParameter("kk");
PrintWriter out = response.getWriter();
Date date = new Date();
String username = request.getParameter("username");
String password = request.getParameter("password");
out.println("<html><body>"+date+username+password+"</body></html><br>");
out.println("<html><body>"+aa+"</body></html><br>");
out.println("<html><body>"+bb+"</body></html><br>");
out.println("<html><body>"+kk+"</body></html><br>");
}
[/code]
[color=red]但是,要是用它来 生成表现层页面显然是很麻烦的,因为都要用servlet的输出流来输出.
如上out.println("<html><body>"+kk+"</body></html><br>");
所以,产生jsp后,它就做控制层.让jsp做表现层,jsp编译后其实也是一个servlet.它其实充当了servlet做为表现层的工作.
servlet,是运行在服务器端的程序,用于处理及响应客户端的请求.[/color]
servlet应该是个中间的部分,对前面和后面部分起的交互,所以,很重要.
而且web.xml的配置都要经过这里,所以好好掌握.
[code]
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String aa = config.getInitParameter("aa");
String bb = config.getServletContext().getInitParameter("bb");
String kk = config.getServletContext().getInitParameter("kk");
PrintWriter out = response.getWriter();
Date date = new Date();
String username = request.getParameter("username");
String password = request.getParameter("password");
out.println("<html><body>"+date+username+password+"</body></html><br>");
out.println("<html><body>"+aa+"</body></html><br>");
out.println("<html><body>"+bb+"</body></html><br>");
out.println("<html><body>"+kk+"</body></html><br>");
}
[/code]
[color=red]但是,要是用它来 生成表现层页面显然是很麻烦的,因为都要用servlet的输出流来输出.
如上out.println("<html><body>"+kk+"</body></html><br>");
所以,产生jsp后,它就做控制层.让jsp做表现层,jsp编译后其实也是一个servlet.它其实充当了servlet做为表现层的工作.
servlet,是运行在服务器端的程序,用于处理及响应客户端的请求.[/color]
servlet应该是个中间的部分,对前面和后面部分起的交互,所以,很重要.
而且web.xml的配置都要经过这里,所以好好掌握.