add.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>计算器</title>
<script type="text/javascript" src="result.js">
</script>
</head>
<body>
<%
String first = request.getParameter("first");
String second = request.getParameter("second");
%>
<form action="/add" method="get">
<input id="first" type="text" name="first" value=first>
<select name="fuhao">
<option>+</option>
<option>-</option>
<option>*</option>
<option>/</option>
</select>
<input id="second" type="text" name="second" value=second>
<input id="count" type="submit" value="=" onclick="add()">
<input id="result" type="text">
</form>
</body>
</html>
addServlet.java
package cn.itsource.servletadd;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/add")
public class AddServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// 得到传来的第一个加数
String first = req.getParameter("first");
// System.out.println(first);
Integer firstadd =null;
// 判断输入的值是否是空值,并转换成Integer
if(first!=null){
firstadd = Integer.parseInt(first);
}
// System.out.println(firstadd);
// 得到第二个加数
String second = req.getParameter("second");
Integer secondadd = null;
// System.out.println(second);
// 判断输入的值是否是空值,并转换成Integer
if(second!=null){
secondadd = Integer.parseInt(second);
}
// 得到传入的符号是什么
String countadd = req.getParameter("fuhao");
// System.out.println(countadd);
// 得到最后的结果
String result = req.getParameter("result");
if("+".equals(countadd)){
Integer rel = firstadd + secondadd;
result = rel.toString();
}
if("-".equals(countadd)){
Integer rel = firstadd - secondadd;
result = rel.toString();
}
if("*".equals(countadd)){
Integer rel = firstadd * secondadd;
result = rel.toString();
}
if("/".equals(countadd)){
Integer rel = firstadd / secondadd;
result = rel.toString();
}
// System.out.println(result);
req.getRequestDispatcher("/add.jsp").forward(req, resp);
}
}
怎么把跳转的值设置到上面的表单中的text里面