对复杂的表单进行判断

最新推荐文章于 2023-05-24 17:17:28 发布

原创最新推荐文章于 2023-05-24 17:17:28 发布 · 417 阅读

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客户端验证;使用java script

<%@ 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>
    <script type="text/javascript">
        function validate()
        {
            var username=document.getElementsByName("username")[0];
            var password=document.getElementsByName("password")[0];
            var gender=document.getElementsByName("gender");
            var interest=document.getElementsByName("interest");
            var comment=document.getElementsByName("comment")[0];

            if(username.value.length<1)
            {
                alert("用户名不能为空");
                return false;
            }
            if(username.value.length<4||username.value.length>10)
            {
                alert("用户名长度在4-10之间");
                return false;
            } 
         if(password.value.length<4||password.value.length>10)
            {
                alert("密码长度在4-10之间");
                return false;
            }
            if(!gender[0].checked&&!gender[1].checked)
            {
                alert("性别必须选择");
                return false;
            } 

            var n=0;

            for(var i=0;i<interest.length;i++)
            {
                if(interest[i].checked)
                {
                   n++;
                } 
            }
            if(n<1)
            {
               alert("兴趣至少选择一个");
               return false;
            }
            if(n>3)
            {
               alert("兴趣最多选择三个");
               return false;
            }
            if(comment.value.length<1)
            {
                alert("必须填写说明");
                return false;
            }


            return true;
  }








    </script>

  </head>

  <body>
      <form onsubmit="return validate();">

            用户名：<input type="text" name="username"><br>
            密码：<input type="password" name="password"><br>
            性别：男<input type="radio" name="gender" value="男">&nbsp;&nbsp;女<input type="radio" name="gender" value="女"><br>
            兴趣：足球<input type="checkbox" name="interest" value="足球">&nbsp;&nbsp;
                       篮球<input type="checkbox" name="interest" value="篮球">&nbsp;&nbsp;
                       羽毛球<input type="checkbox" name="interest" value="羽毛球">&nbsp;&nbsp;
                       网球<input type="checkbox" name="interest" value="羽毛球">&nbsp;&nbsp;<br>
            地址：<select name="address">
            <option value="上海">上海</option>
            <option value="北京">北京</option>
            <option value="天津">天津</option>
         </select><br>
          说明：<textarea rows="5" cols="7" name="comment" ></textarea><br>
    <input type="submit" value="点击确认">&nbsp;&nbsp;&nbsp;<input type="reset" value="重置">  



      </form>
    </body>
</html>

使用服务器进行验证:
第一个jsp页面

<%@ 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>

  </head>

  <body>
      <form action="myloginservlet">

            用户名：<input type="text" name="username"><br>
            密码：<input type="password" name="password"><br>
            性别：男<input type="radio" name="gender" value="男">&nbsp;&nbsp;女<input type="radio" name="gender" value="女"><br>
            兴趣：足球<input type="checkbox" name="interest" value="足球">&nbsp;&nbsp;
                       篮球<input type="checkbox" name="interest" value="篮球">&nbsp;&nbsp;
                       羽毛球<input type="checkbox" name="interest" value="羽毛球">&nbsp;&nbsp;
                       网球<input type="checkbox" name="interest" value="羽毛球">&nbsp;&nbsp;<br>
            地址：<select name="address">
            <option value="上海">上海</option>
            <option value="北京">北京</option>
            <option value="天津">天津</option>
         </select><br>
          说明：<textarea rows="5" cols="7" name="comment" ></textarea><br>
    <input type="submit" value="点击确认">&nbsp;&nbsp;&nbsp;<input type="reset" value="重置">  



      </form>
    </body>
</html>

servlet的处理页面

package firstservlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class myloginservlet extends HttpServlet
{


    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException
    {
        String username=request.getParameter("username");
        String password=request.getParameter("password");
        String gender=request.getParameter("gender");
        String[] interest=request.getParameterValues("interest");
        String address=request.getParameter("address");

        address=new String(address.getBytes("iso-8859-1"),"utf-8");
        String comment=request.getParameter("comment");

        List<String>list=new ArrayList<String>();


        if(null==username||"".equals(username))
        {
            list.add("用户名不能为空");
        }
        else if(username.length()<4)
        {
            list.add("用户名长度最短为4");
        }
        else if(username.length()>10)
        {
            list.add("用户名长度最长为10");
        }

        if(null==password||"".equals(password))
        {
            list.add("密码不能为空");
        }
        else if(password.length()<4)
        {
            list.add("密码长度最短为4");
        } 
        else if(password.length()>10)
        {
            list.add("密码长度最长为10");
        }

        if(gender==null)
        {
            list.add("必须选择性别");
        }

        if(interest==null)
        {
            list.add("兴趣最少为1");

        }
        else if(interest.length>3)
        {
            list.add("兴趣最大为3");
        }

        if(comment==null||"".equals(comment))
        {
            list.add("说明没有填写");
        }

        if(list.isEmpty())
        {

            request.setAttribute("username", username);
            request.setAttribute("password", password);
            request.setAttribute("gender", gender);
            request.setAttribute("interest", interest);
            request.setAttribute("address",address);
            request.setAttribute("comment", comment);

            request.getRequestDispatcher("loginSuccess.jsp").forward(request, response);

        }

        else
        {
            request.setAttribute("error",list );
            request.getRequestDispatcher("loginFailure.jsp").forward(request, response);

        }


    }



}

如果符合要求，跳转到成功的页面

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

    <title>My JSP 'loginSuccess.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">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

  </head>

  <body>
    用户名:<%=request.getAttribute("username") %><br>
    密码：<%=request.getAttribute("password") %><br>
    性别:<%=request.getAttribute("gender") %><br>
    兴趣:<%String[] interest=(String[])request.getAttribute("interest"); 
    for(String str:interest)
    {%>
    <%=str %>&nbsp;%nbsp;
    <%} %>
   地址:<%=request.getAttribute("address") %><br>
   说明：<%=request.getAttribute("comment") %> 



  </body>
</html>

如果填写错误，跳转到错误的页面

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

    <title>My JSP 'loginFailure.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">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

  </head>

  <body>
    错误信息如下：<br><br>

    <%List<String> list = (List<String>)request.getAttribute("error"); %>
    <ul>
       <%for(String str:list) 
       {%>
          <li><font color="#ff0000"><%=str %></font>
        <%} %>

    </ul>
  </body>
</html>