JavaWeb网上图书商城完整项目--验证码

1、首先需要集成下面的jar

2、在web.xml配置验证码的servlet

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" >
  <display-name>BaseServlet</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <filter>
    <filter-name>EncodingFilter</filter-name>
    <filter-class>cn.itcast.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>
  <servlet>
    <servlet-name>VerifyCodeServlet</servlet-name>
    <servlet-class>cn.itcast.vcode.servlet.VerifyCodeServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>VerifyCodeServlet</servlet-name>
    <url-pattern>/VerifyCodeServlet</url-pattern>
  </servlet-mapping>
  
   <servlet>
    <servlet-name>KeServlet</servlet-name>
    <servlet-class>com.weiyuan.test.KeServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>KeServlet</servlet-name>
    <url-pattern>/33</url-pattern>
  </servlet-mapping>
</web-app>

然后编写登陆的jsp文件：

<%@ 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>Insert title here</title>
</head>
<script type="text/javascript">
function changeImg(){
 var img =document.getElementById("img");
 //后面给上一个参数new Date().getTime()每次都不一样，每次都会重新去请求VerifyCodeServlet，而不使用原来缓存中的图片
 img.src="/BaseServlet/VerifyCodeServlet?a="+new Date().getTime();
}
</script>
<body>
<form action="/BaseServlet/LoginServlet" method="post">
<input type="hidden" name="method" value="login"></input>
用户名：<input type="text" name="username"></input></br>
密码：<input type="text" name="pwd"></input></br>
验证码:<input type="text" name="verifyCode"></input></br>
<img id ="img" src="/BaseServlet/VerifyCodeServlet">
<a href="javascript:changeImg()">更换验证码</a></br>
<input type="submit" value="提交"></input>

</form>

</body>
</html>

其中：

BaseServlet是当前的工程项目

在servlet中我们可以通过session获得缓存中session中的验证码，通过客户端在表单中提交的验证码和在session后台中缓存的验证码，我们就可以知道用户提交的验证码是否正确

String verfiyCode= request.getParameter("verifyCode");
        String vcode = (String) request.getSession().getAttribute("vCode");

JavaWeb网上图书商城完整项目--验证码

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