JAVA验证码的实现参考
java验证码的实现(一)
1.ImageServlet类的实现：
package com.mobile.control;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ImageServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
// 生成数字和字母的验证码
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
BufferedImage img = new BufferedImage(68, 22,
BufferedImage.TYPE_INT_RGB);
// 得到该图片的绘图对象
Graphics g = img.getGraphics();
Random r = new Random();
Color c = new Color(200, 150, 255);
g.setColor(c);
// 填充整个图片的颜色
g.fillRect(0, 0, 68, 22);
// 向图片中输出数字和字母
StringBuffer sb = new StringBuffer();
char[] ch = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray();
int index, len = ch.length;
for (int i = 0; i < 4; i ++) {
index = r.nextInt(len);
g.setColor(new Color(r.nextInt(88), r.nextInt(188), r.nextInt
(255)));
g.setFont(new Font("Arial", Font.BOLD | Font.ITALIC, 22));// 输出的
字体和大小
g.drawString("" + ch[index], (i * 15) + 3, 18);//写什么数字，在图片
的什么位置画
sb.append(ch[index]);
}
request.getSession().setAttribute("piccode", sb.toString());
ImageIO.write(img, "JPG", response.getOutputStream());
}
}
2.web.xml中的配置
<servlet>
<servlet-name>ImageServlet</servlet-name>
<servlet-class>com.mobile.control.ImageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ImageServlet</servlet-name>
<url-pattern>/servlet/ImageServlet</url-pattern>
</servlet-mapping>
3.页面源程序
<%@ page contentType="text/html; charset=utf-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>系统登录</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 href="<%=request.getContextPath()%>/jsp/style/stylet.css"
rel="stylesheet" type="text/css">
<mce:script type="text/javascript"><!--
// 重载验证码
function reloadVerifyCode(){
var timenow = new Date().getTime();
document.getElementById("safecode").src="<%
=request.getContextPath()%>/servlet/ImageServlet?d="+timenow;
}
// --></mce:script>
</head>
<body>
<div id="box1">
<div id="tab_box">
<form action="<%=request.getContextPath() %
>/servlet/LoginServlet" method="post" name="login">
<span class="denglu_font_title">欢迎登录</span>
<br />
<br />
<label for="userid" class="yonghuming_font">
用户：
</label>
<input name="userid" type="text" id="userid"
accesskey="n"
tabindex="1"
style="font-family: '宋体'; font-size: 12px;
color: #575757" />
<br />
<br />
<label for="passwd" class="yonghuming_font">
密码：
</label>
<input name="passwd" type="password" id="passwd"
tabindex="2"
style="font-family: '宋体'; font-size: 12px;
color: #575757" />
<br />
<br />
<label for="verifyCode" class="yonghuming_font">
验证码：
</label>
<input type="text" id="verifyCode" name="verifyCode"
size="6" />
<img alt="验证码" id="safecode" src="<%
=request.getContextPath()%>/servlet/ImageServlet">
<a href="javascript:reloadVerifyCode();"
mce_href="javascript:reloadVerifyCode();">看不清楚</a>
<input name="denglu_tijiao" type="submit"
id="denglu_tijiao"
tabindex="3" value="确认" />
<input name="denglu_chongzi" type="reset"
id="denglu_reset"
tabindex="4" value="重置" />
<input type="hidden" name="flag" value="logon">
</form>
<font color='red'></font>
</div>
</div>
</body>
</html>