用kaptcha生成验证码
2024-08-26 21:39:21
1.新建web项目，导入jar包：kaptcha-2.3.jar
2.配置web.xml代码如下：
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list> <!-- kaptcha验证码配置 -->
<servlet> <description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name> <!-- 生成图片的servlet -->
<servlet-name>Kaptcha</servlet-name>
<servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class> <!-- 是否有边框 -->
<init-param>
<param-name>kaptcha.border</param-name>
<param-value>no</param-value>
</init-param> <!-- 字体颜色 -->
<init-param>
<param-name>kaptcha.textproducer.font.color</param-name>
<param-value>red</param-value>
</init-param> <!-- 图片宽度 -->
<init-param>
<param-name>kaptcha.image.width</param-name>
<param-value>135</param-value>
</init-param> <!-- 使用哪些字符生成验证码 -->
<init-param>
<param-name>kaptcha.textproducer.char.string</param-name>
<param-value>ACDEFHKPRSTWX345679</param-value>
</init-param> <!-- 图片高度 -->
<init-param>
<param-name>kaptcha.image.height</param-name>
<param-value>50</param-value>
</init-param> <!-- 字体大小 -->
<init-param>
<param-name>kaptcha.textproducer.font.size</param-name>
<param-value>43</param-value>
</init-param> <!-- 干扰线的颜色 -->
<!-- <init-param>
<param-name>kaptcha.noise.color</param-name>
<param-value>balck</param-value>
</init-param> --> <!-- 字符个数 -->
<init-param>
<param-name>kaptcha.textproducer.char.length</param-name>
<param-value>4</param-value>
</init-param> <!-- 使用哪些字体 -->
<init-param>
<param-name>kaptcha.textproducer.font.names</param-name>
<param-value>Arial</param-value>
</init-param>
</servlet>
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>VerifyServlet</servlet-name>
<servlet-class>cn.hbsi.nzx.servlet.VerifyServlet</servlet-class>
</servlet> <!-- 映射的url -->
<servlet-mapping>
<servlet-name>Kaptcha</servlet-name>
<url-pattern>/Kaptcha.jpg</url-pattern>
</servlet-mapping> </web-app>
3.写表单index.jsp
<%@ page language="java" pageEncoding="UTF-8"%>
<!DOCTYPE HTML>
<html>
<head>
<title>显示KaptchaServlet生成的验证码</title>
<script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-2.1.4.js"></script>
<script type="text/javascript">
//点击切换验证码
function changeVerifyCode(){
$("#yzmImg").attr("src","Kaptcha.jpg?"+Math.floor(Math.random()*100));
} //提交
function doSubmit() { var verifyCodeValue = $("#verifyCode").val();
if(verifyCodeValue.replace(/\s/g,"") == "") {
alert("请输入验证码");
}else {
//提交前先异步检查验证码是否输入正确
var verifyUrl = "${pageContext.request.contextPath}/servlet/VerifyServlet?verifyCode="+verifyCodeValue;
$.ajax({
type:"GET",
url:verifyUrl,
success:function(returnData){
if(returnData!="Y") {
alert("请输入正确的验证码！");
}else {
//验证码正确，进行提交操作
alert("验证码输入正确，提交表单");
}
},
error:function(e){
alert(e);
alert("111");
}
});
}
}
</script>
</head> <body>
<form>
<table>
<tr>
<td>
请输入验证码：
</td>
<td>
<input type="text" name="verifyCode" id="verifyCode">
<img src="Kaptcha.jpg" onclick="changeVerifyCode()" id="yzmImg" style="cursor: pointer;">
<a href="javascript:void(0)" onclick="changeVerifyCode()">看不清，换一张</a>
</td>
</tr>
<tr>
<td>
</td>
<td>
<input type="button" value="提交" onclick="doSubmit()">
</td>
</tr>
</table>
</form>
</body>
</html>
4.写一个servlet验证验证码是否输入正确
/**
*
*/
package cn.hbsi.nzx.servlet; 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 VerifyServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html;charaset=utf-8");
response.setHeader("pragma", "no-cache");
response.setHeader("cache-control", "no-cache");
PrintWriter out = null;
try {
//响应数据
String resultData;
//获取传过来的验证码
String verifyCode = request.getParameter("verifyCode");
System.out.println("verifyCode----"+verifyCode);
if(verifyCode=="") {
resultData = "N";
}else {
//获取kaptcha生成存放在session中的验证码
String kaptchaValue = (String) request.getSession().getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
//比较输入的验证码和实际生成的验证码是否相同
if(kaptchaValue == null || kaptchaValue == ""||!verifyCode.equalsIgnoreCase(kaptchaValue)) {
resultData = "N";
}else {
resultData = "Y";
}
}
out = response.getWriter();
out.write(resultData);
out.flush();
}catch(Exception e) {
e.printStackTrace();
}finally {
if(out != null) {
out.close();
}
}
}
}
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