在线版简易计算器

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package per.mjn._08_cal;
 
import java.io.IOException;
import java.io.PrintWriter;
 
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
// 在线版简易计算器
@WebServlet("/cal")
public class CalServlet extends HttpServlet {
 
    private static final long serialVersionUID = 1L;
 
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        resp.setContentType("text/html;charset=utf-8");
        PrintWriter out = resp.getWriter();
        // -----------------------------------
        // 2. 接收表单中的数据
        String sNum1 = req.getParameter("num1");
        String op = req.getParameter("op");
        String sNum2 = req.getParameter("num2");
        String result = "";
        if(hasLength(sNum1) && hasLength(sNum2)) {
            Integer num1 = Integer.valueOf(sNum1);
            Integer num2 = Integer.valueOf(sNum2);
             
            if("+".equals(op)) {
                result = num1 + num2 + "";
            }
            else if("-".equals(op)) {
                result = num1 - num2 + "";
            }
            else if("*".equals(op)) {
                result = num1 * num2 + "";
            }
            else if("/".equals(op)) {
                result = num1 / num2 + "";
            }
        }
//      System.out.println(sNum1);
//      System.out.println(op);
//      System.out.println(sNum2);
 
        // 1. 输出一个计算器的界面
        out.print("<form action='/day3/cal' method='post'>");
        out.print("<input type='number' name='num1' value='" + sNum1 + "'/>");
        out.print("<select name='op'>");
        out.print("<option>+</option>");
        out.print("<option>-</option>");
        out.print("<option>*</option>");
        out.print("<option>/</option>");
        out.print("</select>");
        out.print("<input type='number' name='num2' value='" + sNum2 + "'/>");
        out.print("<input type='submit' value=' = '/>");
        out.print("<input type='text' value='" + result + "' disabled/>");
    }
     
    private boolean hasLength(String str) {
        return str != null && !"".equals(str.trim());
    }
}

　　

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<!DOCTYPE html>
<html>
<head>
<meta charset='UTF-8'>
<title>Insert title here</title>
</head>
<body>
 
    <form action='' method='post'>
        <input type='number' name='num1'/>
        <select name='op'>
            <option>+</option>
            <option>-</option>
            <option>*</option>
            <option>/</option>
        </select>
        <input type='number' name='num2'/>
        <input type='submit' value=' = '/>
        <input type='text' value='' disabled/>
    </form>
</body>
</html>

　　

posted @   青衫客36  阅读(400)  评论(0)  编辑  收藏  举报
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