实现提交表单以后判断输入的信息是否符合条件
若符合条件
先新建servlet
Sevlet的两种声明方式，二选一即可
再到web.xml里注册
register.jsp就是表单的界面
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"
errorPage="error.jsp"%>
<%
String ser_msg = (String)request.getAttribute("server_info");
%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<link href="css/style.css" rel="stylesheet" type="text/css"/>
<style>
dl{width: 500px;}
dt{width: 80px; float: left; height: 40px; text-align: right;}
dd{width: 360px; float: left; height: 40px; margin: 0px 0px 0px 10px;}
input[type=text],input[type=password]{width: 300px; height: 25px; border-radius: 10px; border solid 2px #999;}
#main{
width:400px;
margin:auto;
}
#main h2{
text-aligh:center;
margin-left:100px;
}
#info{color:#f00; font-weight:bold;}
</style>
<script>
</script>
<body>
<div id="main" >
<h2>用户注册</h2>
<!-- 提交，发生动作 reg_action.jsp-->
<form action="reg" method="post">
<dl>
<dt>用户名：</dt><dd><input type="text" name="usercode"></dd>
<dt>密码：</dt><dd><input type="password" name="userpass"></dd>
<dt>确认密码：</dt><dd><input type="password" name="confpass"></dd>
<dt>姓名：</dt><dd><input type="text" name="username"></dd>
<dt>Email：</dt><dd><input type="text" name="email"></dd>
<dt>性别：</dt><dd><input type="radio" name="gender" value="0" checked>
男 <input type="radio" name="gender" value="1">女</dd>
<dt>职业：</dt><dd><select name="occupation">
<option value="a">战士（Warrior）</option>
<option value="b">坦克（Tank）</option>
<option value="c">刺客（Assassin）</option>
<option value="d">法师（Mage）</option>
<option value="e">射手（Archer）</option>
<option value="f">辅助（Support）</option>
</select></dd>
<dt>兴趣爱好：</dt><dd><input type="checkbox" name="hobby" value="吃饭">吃饭
<input type="checkbox" name="hobby" value="睡觉">睡觉
<input type="checkbox" name="hobby" value="豆豆">打豆豆</dd>
<dt>出生日期：</dt><dd><input type="date" name="birthday"></dd>
<dt>照片：</dt><dd><input type="file" name="photo"></dd>
<dt>自我介绍：</dt><dd><textarea name="introduce"></textarea></dd>
<dt></dt><dd><input type="checkbox" name="read" value="1">我已阅读《用户协议》</dd> <%=ser_msg == null? "":"<dt></dt><dd><span id='info'>"+ser_msg+"</span></dd>"%>
<dt></dt><dd><input type="submit" value="注 册">
<input type="reset" value="取 消"></dd>
</dl>
</form>
</div>
</body>
</html>
在servlet里的doGet里写判断语句
前端register.jsp获取servlet传来的msg
doGet代码
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
String ucode = request.getParameter("usercode");
String msg;
RequestDispatcher rd = request.getRequestDispatcher("register.jsp");
PrintWriter out = response.getWriter();
out.print("usercode: " + ucode);
if(ucode.equals("管理员")){
//response.sendRedirect("register.jsp");页面跳转
msg = ucode + "不能使用！";
request.setAttribute("server_info", msg);
rd.forward(request, response);
}
if(ucode.length()<8 || ucode.length()>20){
msg = ucode+"长度不符合要求";
request.setAttribute("server_info", msg);
rd.forward(request, response);
}
if(!Tools.checkChar(ucode)) {
msg = ucode+"包含非法字符";
request.setAttribute("server_info", msg);
rd.forward(request, response);
}
}
Tools.java是我用来专门处理不符合条件的一个java代码，全写进servlet里太乱了，之后要写入到Tools里
servlet前面导入一下
Tools.java的代码如下：
package com.xx17.cys.base;
public class Tools {
public static int getNum(String str) {
int result = 0;
try{
if(str.length()>0) {
result = Integer.parseInt(str);
}
}catch(Exception e){
}
return result;
}
/*
* 判断是否包含非法字符
* 返回：包含（false）、不包含（true）
* 修改：cys,2019-4-4
* */
public static boolean checkChar(String str) {
boolean result = true;
String validStr="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
for(int i=0; i<str.length();i++) {
String s = str.substring(i, i+1);
if(validStr.indexOf(s)==-1) {
System.out.println(s+"非法字符！！！");
result = false;
break;
}
}
return result;
}
}