用JSP做计算器（二）

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这次把MVC模型的Control分割出来，利用JSP(V)+Servlet(C)+JavaBean(M) 重构上篇的计算器：

JavaBean依然采用上篇的

JSP代码：

<%@ page language="java" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <body>    <!-- V -->    <jsp:useBean id="cb" class="cn.itcast.web.jsp.CalBean" scope="request"/>    <jsp:getProperty name="cb" property="firstNum"/>    <jsp:getProperty name="cb" property="operator"/>    <jsp:getProperty name="cb" property="secondNum"/>    =    <jsp:getProperty name="cb" property="result"/>  <hr/>  <!-- V --><form action="/day10/CalServlet" method="post"><table border="1" align="center"><caption>间单计算器</caption><tr><th>第一个参数：</th><td><input type="text" name="firstNum"value='<jsp:getProperty name="cb" property="firstNum"/>'/></td></tr><tr><th>运算符</th><td><select name="operator"><option value="-">-</option><option value="+" selected>+</option><option value="*">*</option><option value="/">/</option></select></td></tr><tr><th>第二个参数：</th><td><input type="text" name="secondNum"value='<jsp:getProperty name="cb" property="secondNum"/>'/></td></tr><tr><td colspan="2" align="center"><input style="width:200px" type="submit" value="计算"/></td></tr></table></form>  </body></html>

Servlet设计：

import java.io.Exception;import java.util.Enumeration;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.commons.beanutils.BeanUtils;public class CalServlet extends HttpServlet {public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {Enumeration<String> enums = request.getParameterNames();CalBean cb = new CalBean();while(enums.hasMoreElements()){String key = enums.nextElement();String[] values = request.getParameterValues(key);try {BeanUtils.setProperty(cb,key,values);} catch (Exception e) {e.printStackTrace();}}cb.cal();request.setAttribute("cb",cb);request.getRequestDispatcher("/cal_2.jsp").forward(request,response);}}

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