一：View cal.jsp
1 <%@page language="java" contentType="text/html; charset=utf-8" 2 pageEncoding="utf-8"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 7 <title>采用三目运算符获取运算符</title> 8 </head> 9 <body> 10 <form action="CalServlet" method="post" > 11 操作数1：<input type="text" name="num1" value="${requestScope.newCal.num1}"><br> 12 运算： <input type="radio" name="op" value="+" ${requestScope.newCal.op=="+"? "checked": " "}>+ 13 <input type="radio" name="op" value="-" ${requestScope.newCal.op=="-"? "checked" : " "}>- 14 <input type="radio" name="op" value="*" ${requestScope.newCal.op=="*"? "checked" : " "}>* 15 <input type="radio" name="op" value="/" ${requestScope.newCal.op=="/"? "checked" : " "}>/<br> 16 操作数2：<input type="text" name="num2" value="${requestScope.newCal.num2}"><br> 17 <input type="submit" value="计算" ><br> 18 结果：<input type="text" value="${requestScope.newResult}"> 19 </form> 20 </body> 21 </html>
二：Model Calculator.java
1 package nuc.sw.cal.bean; 2 3 public class Calculator { 4 private float num1; 5 private String op; 6 private float num2; 7 public float getNum1() { 8 return num1; 9 } 10 public void setNum1(float num1) { 11 this.num1 = num1; 12 } 13 public String getOp() { 14 return op; 15 } 16 public void setOp(String op) { 17 this.op = op; 18 } 19 public float getNum2() { 20 return num2; 21 } 22 public void setNum2(float num2) { 23 this.num2 = num2; 24 } 25 26 }
三：CalServlet.java
1 package nuc.sw.cal.servlet; 2 3 import java.io.IOException; 4 import javax.servlet.ServletException; 5 import javax.servlet.http.HttpServlet; 6 import javax.servlet.http.HttpServletRequest; 7 import javax.servlet.http.HttpServletResponse; 8 9 import nuc.sw.cal.bean.Calculator; 10 11 /** 12 * Servlet implementation class CalServlet 13 */ 14 public class CalServlet extends HttpServlet { 15 private static final long serialVersionUID = 1L; 16 17 /** 18 * @see HttpServlet#HttpServlet() 19 */ 20 public CalServlet() { 21 super(); 22 // TODO Auto-generated constructor stub 23 } 24 25 /** 26 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) 27 */ 28 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 29 // TODO Auto-generated method stub 30 response.getWriter().append("Served at: ").append(request.getContextPath()); 31 } 32 33 /** 34 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) 35 */ 36 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 37 // TODO Auto-generated method stub 38 39 //form中method若由get改变为post,只需在doPost里调用doGet方法doGet(request, response);就可以，不需要重新写方法。 40 //第一次请求为Get 之后为Post 41 42 //接受表单提交的数据，并将数据封装在bean中 43 Calculator cal=new Calculator(); 44 45 cal.setNum1(Float.parseFloat(request.getParameter("num1"))); 46 cal.setOp(request.getParameter("op")); 47 cal.setNum2(Float.parseFloat(request.getParameter("num2"))); 48 49 float result=0; 50 switch(cal.getOp().charAt(0)){ 51 //根据运算符做相应的操作 52 case '+': 53 result=cal.getNum1()+cal.getNum2(); 54 break; 55 case '-': 56 result=cal.getNum1()-cal.getNum2(); 57 break; 58 case '*': 59 result=cal.getNum1()*cal.getNum2(); 60 break; 61 case '/': 62 result=cal.getNum1()/cal.getNum2(); 63 } 64 65 //将对象和结果保存到request域中 66 //之后的模型中时常会用到传递 整个对象 67 request.setAttribute("newCal",cal); 68 request.setAttribute("newResult",result); 69 //以服务器端跳转页面 70 request.getRequestDispatcher("cal.jsp").forward(request, response); 71 72 /* 73 1.服务器端跳转 作用域为request 有返回结果而且地址栏改变，变为现页面 请求转发 74 request.getRequestDispatcher("cal.jsp").forward(request, response); 75 2.客户端跳转（2次请求） 作用域为session 无返回结果而且地址栏不变，仍是前一个页面 请求重定向 76 request.sendRedirect("cal.jsp"); 77 */ 78 } 79 80 }
四：项目建立结果及运行结果：
