20170828_chr_MyCalculator 用servlet编写计算器程序

---

20170828_chr_MyCalculator

• /20170828_chr_MyCalculator/src/nuc/sw/servlet/CalServlet.java

package nuc.sw.servlet;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import nuc.sw.vo.Calculator;public class CalServlet extends HttpServlet {    /**         * Destruction of the servlet. <br>         */    public void destroy() {        super.destroy(); // Just puts "destroy" string in log        // Put your code here    }    /**         * The doDelete method of the servlet. <br>         *         * This method is called when a HTTP delete request is received.         *          * @param request the request send by the client to the server         * @param response the response send by the server to the client         * @throws ServletException if an error occurred         * @throws IOException if an error occurred         */    public void doDelete(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        // Put your code here    }    /**         * The doGet method of the servlet. <br>         *         * This method is called when a form has its tag value method equals to get.         *          * @param request the request send by the client to the server         * @param response the response send by the server to the client         * @throws ServletException if an error occurred         * @throws IOException if an error occurred         */    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        Calculator cal = new Calculator();        cal.setNum1(Float.parseFloat(request.getParameter("num1")));        cal.setNum2(Float.parseFloat(request.getParameter("num2")));        cal.setOp(request.getParameter("op"));        float result = 0;        switch (cal.getOp().charAt(0)) {            case '+':                result = cal.getNum1() + cal.getNum2();break;            case '-':                result = cal.getNum1() - cal.getNum2();break;            case '*':                result = cal.getNum1() * cal.getNum2();break;            case '/':                result = cal.getNum1() / cal.getNum2();break;        }        request.setAttribute("cal", cal);        request.setAttribute("result", result);        request.getRequestDispatcher("cal.jsp").forward(request, response);    }    /**         * The doPost method of the servlet. <br>         *         * This method is called when a form has its tag value method equals to post.         *          * @param request the request send by the client to the server         * @param response the response send by the server to the client         * @throws ServletException if an error occurred         * @throws IOException if an error occurred         */    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    }    /**         * Initialization of the servlet. <br>         *         * @throws ServletException if an error occurs         */    public void init() throws ServletException {        // Put your code here    }}

• /20170828_chr_MyCalculator/src/nuc/sw/vo/Calculator.java

package nuc.sw.vo;public class Calculator {    private float num1;    private String op;    private float num2;        public float getNum1() {            return num1;        }        public void setNum1(float num1) {            this.num1 = num1;        }        public String getOp() {            return op;        }        public void setOp(String op) {            this.op = op;        }        public float getNum2() {            return num2;        }        public void setNum2(float num2) {            this.num2 = num2;        }}

• /20170828_chr_MyCalculator/WebRoot/WEB-INF/web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">  <display-name>20170828_chr_MyCalculator</display-name>  <display-name>CalServlet</display-name>  <description>This is the description of my J2EE component</description>  <servlet>    <servlet-name>CalServlet</servlet-name>    <servlet-class>nuc.sw.servlet.CalServlet</servlet-class>  </servlet>  <servlet-mapping>    <servlet-name>CalServlet</servlet-name>    <url-pattern>/CalServlet</url-pattern>  </servlet-mapping>  <welcome-file-list>    <welcome-file>index.html</welcome-file>    <welcome-file>index.htm</welcome-file>    <welcome-file>index.jsp</welcome-file>    <welcome-file>default.html</welcome-file>    <welcome-file>default.htm</welcome-file>    <welcome-file>default.jsp</welcome-file>  </welcome-file-list></web-app>

• /20170828_chr_MyCalculator/WebRoot/cal.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head>    <title>简易计算器</title></head><body><form action="CalServlet" method="get">    操作数1：<input type="text" name="num1"value="${cal.num1}"><br>    运算符：<input type="radio" name="op" value="+"${requestScope.cal.op=='+'?"checked":""}>+    <input type="radio" name="op" value="-"${requestScope.cal.op=='-'?"checked":""}>-    <input type="radio" name="op" value="*"${requestScope.cal.op=='*'?"checked":""}>*    <input type="radio" name="op" value="/"${requestScope.cal.op=='/'?"checked":""}>/<br>    操作数2：<input type="text" name="num2" value="${cal.num2}"><br>    <input type="submit" value="计算"><br>    结果：<input type="text" value=" ${requestScope.result}" >    </form></body></html>