用JSP做计算器（二）

最新推荐文章于 2023-02-19 20:45:23 发布

boxyuan

最新推荐文章于 2023-02-19 20:45:23 发布

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分类专栏： JSP 文章标签： JavaBean jsp web Java servlet

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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);
	}
}