java 验证码代码

[java]代码库

产生图片servlet 

import java.awt.Color; 
import java.awt.Font; 
import java.awt.Graphics2D; 
import java.awt.image.BufferedImage; 
import java.util.Random; 

import javax.imageio.ImageIO; 
import javax.servlet.ServletException; 
import javax.servlet.ServletOutputStream; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import javax.servlet.http.HttpSession; 

/** 
* Package name : com.skcc.sample.action 
* File name : VerifyCodeServlet.java 
* Description : VerifyCodeServlet 
*/
public class VerifyCodeServlet extends HttpServlet { 

/** 
* 验证码图片的宽度。 
*/
private int width = 60; 

/** 
* 验证码图片的高度。 
*/
private int height = 20; 

/** 
* 验证码字符个数 
*/
private int codeCount = 4; 

/** 
* xx 
*/
private int xx = 0; 

/** 
* 字体高度 
*/
private int fontHeight; 

/** 
* codeY 
*/
private int codeY; 

/** 
* codeSequence 
*/
char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 
'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' }; 

/** 
* 初始化验证图片属性 
*/
public void init() throws ServletException { 
// 从web.xml中获取初始信息 
// 宽度 
String strWidth = this.getInitParameter("width"); 
// 高度 
String strHeight = this.getInitParameter("height"); 
// 字符个数 
String strCodeCount = this.getInitParameter("codeCount"); 

// 将配置的信息转换成数值 
try { 
if (strWidth != null && strWidth.length() != 0) { 
width = Integer.parseInt(strWidth); 
} 
if (strHeight != null && strHeight.length() != 0) { 
height = Integer.parseInt(strHeight); 
} 
if (strCodeCount != null && strCodeCount.length() != 0) { 
codeCount = Integer.parseInt(strCodeCount); 
} 
} catch (NumberFormatException e) { 
e.printStackTrace(); 
} 

xx = width / (codeCount + 1); 
fontHeight = height - 2; 
codeY = height - 4; 

} 

/** 
* @param req 
* @param resp 
* @throws ServletException 
* @throws java.io.IOException 
*/
protected void service(HttpServletRequest req, HttpServletResponse resp) 
throws ServletException, java.io.IOException { 

// 定义图像buffer 
BufferedImage buffImg = new BufferedImage(width, height, 
BufferedImage.TYPE_INT_RGB); 
Graphics2D gd = buffImg.createGraphics(); 

// 创建一个随机数生成器类 
Random random = new Random(); 

// 将图像填充为白色 
gd.setColor(Color.WHITE); 
gd.fillRect(0, 0, width, height); 

// 创建字体，字体的大小应该根据图片的高度来定。 
Font font = new Font("Fixedsys", Font.PLAIN, fontHeight); 
// 设置字体。 
gd.setFont(font); 

// 画边框。 
gd.setColor(Color.BLACK); 
gd.drawRect(0, 0, width - 1, height - 1); 

// 随机产生160条干扰线，使图象中的认证码不易被其它程序探测到。 
gd.setColor(Color.BLACK); 
for (int i = 0; i < 160; i++) { 
int x = random.nextInt(width); 
int y = random.nextInt(height); 
int xl = random.nextInt(12); 
int yl = random.nextInt(12); 
gd.drawLine(x, y, x + xl, y + yl); 
} 

// randomCode用于保存随机产生的验证码，以便用户登录后进行验证。 
StringBuffer randomCode = new StringBuffer(); 
int red = 0, green = 0, blue = 0; 

// 随机产生codeCount数字的验证码。 
for (int i = 0; i < codeCount; i++) { 
// 得到随机产生的验证码数字。 
String strRand = String.valueOf(codeSequence[random.nextInt(36)]); 
// 产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同。 
red = random.nextInt(255); 
green = random.nextInt(255); 
blue = random.nextInt(255); 

// 用随机产生的颜色将验证码绘制到图像中。 
gd.setColor(new Color(red, green, blue)); 
gd.drawString(strRand, (i + 1) * xx, codeY); 

// 将产生的四个随机数组合在一起。 
randomCode.append(strRand); 
} 
// 将四位数字的验证码保存到Session中。 
HttpSession session = req.getSession(); 
session.setAttribute("validateCode", randomCode.toString()); 

// 禁止图像缓存。 
resp.setHeader("Pragma", "no-cache"); 
resp.setHeader("Cache-Control", "no-cache"); 
resp.setDateHeader("Expires", 0); 

resp.setContentType("image/jpeg"); 

// 将图像输出到Servlet输出流中。 
ServletOutputStream sos = resp.getOutputStream(); 
ImageIO.write(buffImg, "jpeg", sos); 
sos.close(); 
} 

} 

产生结果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; 

/** 
* Package name : com.skcc.sample.action 
* File name : ResultServlet.java 
* Author : Administrator 
* Date : 2008-9-4 
* Description : ResultServlet 
*/
public class ResultServlet extends HttpServlet { 

/** 
* The doGet method of the servlet. <br> 
* 
* This method is called when a form has its tag value method equals to get. 
* 
* @param request the request send by the client to the server 
* @param response the response send by the server to the client 
* @throws ServletException if an error occurred 
* @throws IOException if an error occurred 
*/
public void doGet(HttpServletRequest request, HttpServletResponse response) 
throws ServletException, IOException { 

doPost(request, response); 
} 

/** 
* The doPost method of the servlet. <br> 
* 
* This method is called when a form has its tag value method equals to post. 
* 
* @param request the request send by the client to the server 
* @param response the response send by the server to the client 
* @throws ServletException if an error occurred 
* @throws IOException if an error occurred 
*/
public void doPost(HttpServletRequest request, HttpServletResponse response) 
throws ServletException, IOException { 

response.setContentType("text/html;charset=utf-8"); 
String validateC = (String) request.getSession().getAttribute("validateCode"); 
String veryCode = request.getParameter("veryCode"); 
PrintWriter out = response.getWriter(); 
if(veryCode==null||"".equals(veryCode)){ 
out.println("验证码为空"); 
}else{ 
if(validateC.equals(veryCode)){ 
out.println("验证码正确"); 
}else{ 
out.println("验证码错误"); 
} 
} 
out.flush(); 
out.close(); 
} 

} 
js文件 

function changeImg(){ 
var imgSrc = $("#imgObj"); 
var src = imgSrc.attr("src"); 
imgSrc.attr("src",chgUrl(src)); 
} 
//时间戳 
//为了使每次生成图片不一致，即不让浏览器读缓存，所以需要加上时间戳 
function chgUrl(url){ 
var timestamp = (new Date()).valueOf(); 
url = url.substring(0,17); 
if((url.indexOf("&")>=0)){ 
url = url + "×tamp=" + timestamp; 
}else{ 
url = url + "?timestamp=" + timestamp; 
} 
return url; 
} 

function isRightCode(){ 
var code = $("#veryCode").attr("value"); 
code = "c=" + code; 
$.ajax({ 
type:"POST", 
url:"resultServlet", 
data:code, 
success:callback 
}); 
} 

function callback(data){ 
$("#info").html(data); 
} 
页面verifyCode.jsp 

<%@ 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"> 
<script type="text/javascript" src="js/verifyCode.js"></script> 
<script type="text/javascript" src="js/jquery.js"></script> 
<title>test verify code</title> 
</head> 
<body> 
<input id="veryCode" name="veryCode" type="text"/> 
<img id="imgObj" alt="" src="verifyCodeServlet"/> 
<a href="#" onclick="changeImg()">换一张</a> 
<input type="button" value="验证" onclick="isRightCode()"/> 
<div id="info"></div> 
</body> 
</html> 

最后记得配好web.xml 

<servlet> 
< servlet-name>VerifyCodeServlet</servlet-name> 
< servlet-class>com.sample.action.VerifyCodeServlet</servlet-class> 
</servlet> 
<servlet> 
< servlet-name>ResultServlet</servlet-name> 
< servlet-class>com.sample.action.ResultServlet</servlet-class> 
</servlet> 
< servlet-mapping> 
< servlet-name>VerifyCodeServlet</servlet-name> 
< url-pattern>/verifyCodeServlet</url-pattern> 
< /servlet-mapping> 
<servlet-mapping> 
< servlet-name>ResultServlet</servlet-name> 
< url-pattern>/resultServlet</url-pattern> 
< /servlet-mapping>

//源代码片段来自云代码http://yuncode.net