前言：为了能够清晰的理解mvc架构，以一个简单的mvc架构web应用为例。例子为一个beer项目，用户可通过页面选择啤酒的种类，服务端根据用户的选择，给出相应的推荐。
涉及到的代码：
view层：form.html 》 用户选择页面
result.jsp 》 服务器返回推荐页面
model层：BeerExpert.java 》 处理用户选择并给出推荐的逻辑处理
control层：BeerSelect.java 》 负责接收view层传入的数据，并将数据交给model层处理，然后将处理结果重定向到result.jsp
web架构：
代码实现：
form.html
<html> <body> <h1 align="Center">Beer Selection Page</h1> <form method="Post" action="SelectBeer.do"> <p>Select beer charcteristics</p> Color: <select name="color" size="1"> <option value="light">light </option> <option value="amber">amber </option> <option value="brown">brown </option> </select> <br><br> <center> <input type="submit"> </center> </form> </body> </html>
result.jsp
<%@ page import="java.util.*" %> <html> <body> <h1 align="center">Beer Recommendations JSP</h1> <% List styles = (List)request.getAttribute("styles"); Iterator it = styles.iterator(); while(it.hasNext()){ out.print("<br>try:: "+it.next()); } %> </body> </html>
web.xml
<?xml version="1.0" encoding="ISO-8859-1" ?> <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0"> <servlet> <servlet-name>MyBeer</servlet-name> <servlet-class>com.example.web.BeerSelect</servlet-class> </servlet> <servlet-mapping> <servlet-name>MyBeer</servlet-name> <url-pattern>/SelectBeer.do</url-pattern> </servlet-mapping> </web-app>
BeerSelect.java
package com.example.web; import com.example.model.*; import javax.servlet.*; import javax.servlet.http.*; import java.io.*; import java.util.*; public class BeerSelect extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException{ response.setContentType("text/html"); String c = request.getParameter("color"); //PrintWriter out = response.getWriter(); BeerExpert expert = new BeerExpert(); List ls = expert.getBrands(c); //Iterator it = ls.iterator(); //while(it.hasNext()){ // out.println("<br> try:"+it.next()); //} //out.println("Beer Selection Advice<br>"); //ot.println("<br> Got beer color"+c); request.setAttribute("styles",ls); RequestDispatcher view = request.getRequestDispatcher("result.jsp"); view.forward(request,response); } }
BeerExpert.java
package com.example.model; import java.util.*; public class BeerExpert { public List getBrands(String color){ List<String> brands = new ArrayList<String>(); if(color.equals("amber")) { brands.add("Jack Amber"); brands.add("Red Moose"); } else { brands.add("Jail Pala Ale"); brands.add("Gout Stout"); } return(brands); } }
测试Beer应用：
