验证码不正确还是会跳转到LoginServlet
我想做到验证码错误不跳转应该怎么实现，代码如下
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%
String basePath = request.getScheme()+":"+"//"+request.getServerName()+":"+request.getServerPort()+"/"
+request.getServletContext().getContextPath()+"/";
%>
<!DOCTYPE html>
<html>
<head>
<base href="<%=basePath%>">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>登录页面</title>
<style type="text/css">
a
{
text-decoration:none;
font-size:12px;
color:#288bc4;
}
a:hover
{
text-decoration:underline;
}
img{
margin:auto 0px;
}
</style>
</head>
<body>
<center>
<h1>用户登录</h1>
<form action="<%=basePath%>/LoginServlet" method="post" onsubmit="return validateCode()">
<table width="300px" cellspacing="0px" cellpadding="0px" border="1px">
<tr>
<td>用户名</td>
<td colspan="2"><input type="text" name="username" placeholder="用户名为3-12位字母数字或下划线组合"></td>
</tr>
<tr>
<td>密 码</td>
<td colspan="2"><input type="password" name="password" placeholder="长度为5-12位字母数字或下划线组合" ></td>
</tr>
<tr>
<td>验证码</td>
<td style="border-right-style:none;">
<input type="text" name="checkCode" maxlength="4" placeholder="请输入验证码" id="code">
<img src="<%=basePath%>/kaptcha.jpg" id="changecode"/>
</td>
</tr>
<tr>
<td colspan="3" style="text-align:center">
<input type="submit" value="登录" id="login">
<input type="reset" value="取消">
</td>
</tr>
</table>
</form>
</center>
<script src="js/jquery-1.12.4.min.js"></script>
<script>
$(function () {
$("#changecode").on("click",function () {
$(this).attr("src","<%=basePath%>/kaptcha.jpg?d="+new Date().getTime());
});
$("#login").on("click",function () {
var code = $("#code").val();
var params = {"code":code};
$.post("<%=basePath%>/LoginServlet",params,function (data) {
if (data=="fail") {
alert("验证码输入有误");
$("#code").val("").focus();
}
});
});
});
</script>
</body>
</html>LoginServlet
package com.imooc.servlet;
import com.google.code.kaptcha.Constants;
import com.sun.tools.javac.code.Attribute;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintStream;
import java.io.PrintWriter;
@WebServlet(name = "LoginServlet")
public class LoginServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//check code
response.setCharacterEncoding("UTF-8");
PrintWriter out = response.getWriter();
String code = request.getParameter("checkCode");
String sessionCode = (String) request.getSession().getAttribute("kcode");
if(code!=null && sessionCode!=null){
if (code.equalsIgnoreCase(sessionCode)){
}
}else {
out.print("fail");
}
out.flush();
out.close();
//
}
}<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<!--验证码-->
<servlet>
<servlet-name>Kaptcha</servlet-name>
<servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class>
<init-param>
<param-name>kaptcha.border</param-name>
<param-value>no</param-value>
</init-param>
<init-param>
<param-name>kaptcha.image.width</param-name>
<param-value>100</param-value>
</init-param>
<init-param>
<param-name>kaptcha.image.height</param-name>
<param-value>20</param-value>
</init-param>
<init-param>
<param-name>kaptcha.textproducer.font.size</param-name>
<param-value>16</param-value>
</init-param>
<init-param>
<param-name>kaptcha.textproducer.char.string</param-name>
<param-value>qwertyuiopasdfghjklzxcvbnm123456789</param-value>
</init-param>
<init-param>
<param-name>kaptcha.textproducer.char.length</param-name>
<param-value>4</param-value>
</init-param>
<init-param>
<param-name>kaptcha.noise.impl</param-name>
<param-value>com.google.code.kaptcha.impl.NoNoise</param-value>
</init-param>
<init-param>
<!--session.setAttribute("kcode",生成好的验证吗)-->
<param-name>kaptcha.session.key</param-name>
<param-value>kcode</param-value>
</init-param>
<init-param>
<param-name>kaptcha.textproducer.font.color </param-name>
<param-value>blue</param-value>
</init-param>
<init-param>
<param-name>kaptcha.obscurificator.impl</param-name>
<param-value>com.google.code.kaptcha.impl.ShadowGimpy</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>Kaptcha</servlet-name>
<url-pattern>/kaptcha.jpg</url-pattern>
</servlet-mapping>
<!--验证码-->
<!--编码过滤-->
<filter>
<filter-name>EncodingFilter</filter-name>
<filter-class>com.imooc.filter.EncodingFilter</filter-class>
<init-param>
<param-name>charset</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>EncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!--编码过滤-->
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.imooc.servlet.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
</web-app>0
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3回答
chrismorgen
2018-07-18 16:05:11
你获取用户的验证码时，应该是code而不是checkCode。如果我的建议解决了你的问题，请采纳，祝学习愉快~
chrismorgen
2018-07-18 11:03:55
根据你的代码是要跳转到LoginServlet中的，如下图所示，可以在LoginServlet添加一个跳转的操作，如果验证码失败，就跳转到Login.jsp页面进行重新输入。祝学习愉快~
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