package com.tan.guo;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;
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;
/**
* 功能：
* @author TanZi
* @time 2015-4-11上午11:16:21
*/
public class ImageServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
BufferedImage bi=new BufferedImage(68, 22, BufferedImage.TYPE_INT_RGB);//创建一个图片
Graphics g=bi.getGraphics(); //创建画笔
Color c=new Color(200,150,225);
g.setColor(c);
g.fillRect(0, 0, 68, 22); //设置画的位置
char[] ch="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray(); //设置画的内容
Random r=new Random();
int len=ch.length,index;
StringBuffer sb=new StringBuffer(); //用来保存生成的验证码字符
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.drawString(ch[index]+"", (i*15)+3, 18);
sb.append(ch[index]);
}
request.getSession().setAttribute("piccode", sb.toString()); //把生成的验证码字符放到session
ImageIO.write(bi, "JPG", response.getOutputStream()); //写回图片
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doGet(request, response);
}
}
jsp上的编写：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</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 rel="stylesheet" type="text/css" href="styles.css">
-->
<script type="text/javascript">
function reloadCode(){
var time=new Date().getTime();
document.getElementById("imagecode").src="<%=request.getContextPath()%>/servlet/ImageServlet?d="+time;
}
</script>
</head>
<body>
验证码：<input type="text" name="checkcode"/>
<img alt="验证码" id="imagecode" src="<%=request.getContextPath()%>/servlet/ImageServlet"/>
<a href="javascript:reloadCode();">看不清</a>
<br>
</body>
</html>
时间： 2024-10-25 01:42:56