MVC轻量web应用

时间：2023-12-26 21:57:13

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：

MVC轻量web应用

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：

MVC轻量web应用

MVC轻量web应用

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