11 java 王少飞-java中的jsp小节四

最新推荐文章于 2013-03-08 14:49:29 发布

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本文介绍了如何利用JSP和Servlet完成表单验证，通过接收并处理用户提交的信息，实现姓名、性别、邮箱和爱好的展示。重点在于处理空值的情况，确保用户输入的有效性。

使用jsp+servlet完成一个表单验证，通过表单提交信息给Servlet，Servlet获取到信息后，处理，把信息放到request对象中，如果用户提交的姓名为空，不能跳转，否则，将信息全部显示出来。

全部文件两个jsp页面（一个首页，一个输出结果），一个servlet

首页----------------

<%@ page Xlanguage="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>
<base href="<%=basePath%>">

<title>My JSP 'register.jsp' starting page</title>

</head>

输出------------------------

<%@ page Xlanguage="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>
<base href="<%=basePath%>">

<title>My JSP 'result.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">

</head>

<body>
<%
out.print("姓名："+request.getAttribute("username")+"<br/>");
out.print("性别："+request.getAttribute("sex")+"<br/>");
out.print("E-mail："+request.getAttribute("mail")+"<br/>");
out.print("爱好："+request.getAttribute("likes"));
%>
</body>
</html>

一个servlet-------------

package com.csdn.register;

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;

public class RegisterUser extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
String username=request.getParameter("username");
String sex=request.getParameter("sex");
String mail=request.getParameter("e-mail");
String[] likes=request.getParameterValues("like");
String loves=new String();
if(username.equals("")){
out.write("用户名不能为空");
return;
}
if(sex==null){
out.write("请选择性别");
return;
}
if(mail.equals("")){
out.write("请输入邮箱");
return;
}
if(likes==null){
out.write("请选择爱好");
return;
}
for(int i=0;i<likes.length;i++){
loves+=likes[i]+" ";
}
request.setAttribute("username", username);
request.setAttribute("sex", sex);
request.setAttribute("mail", mail);
request.setAttribute("likes", loves);
request.getRequestDispatcher("./RegisterUser/result.jsp").forward(request, response);
}