网上找到一个jsp验证码程序,想试着自已写写,可是就是写不成功,各位帮忙看看,指导一下。先谢了
package com.test.validatecode;import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;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;public class CheckCodeServlet extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
private static int WIDTH = 80;
private static int HEIGHT = 25; public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("GBK");
response.setContentType("text/html;charset=GBK"); HttpSession session = request.getSession();
response.setContentType("images/jpg");
ServletOutputStream sos = response.getOutputStream(); // 设置浏览器不要缓存数据
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
// 创建内存图象并获得其图形上下文
BufferedImage image = new BufferedImage(WIDTH, HEIGHT,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
// 产生随机的认证码
char[] rands = this.generateCheckCode();
// 产生图像
this.drawBackground(g);
this.drawRands(g, rands);
// 结束图像的绘制过程,完成图像 g.dispose();
// 将图像输出到客户端
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ImageIO.write(image, "JPEG", bos);
byte[] buf = bos.toByteArray();
response.setContentLength(buf.length);
// 下面的语句也可写成:bos.writeTo(sos);
sos.write(buf);
bos.close();
sos.close(); // 将当前验证码存入到Session中
session.setAttribute("check_code", new String(rands));
// 直接使用下面的代码将有问题,Session对象必须在提交响应前获得
// request.getSession().setAttribute("check_code",new String(rands));
} // 定义验证码的字符表
public char[] generateCheckCode() {
String chars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
char[] rands = new char[4];
for (int i = 0; i < 4; i++) {
int rand = (int) (Math.random() * 62);
rands[i] = chars.charAt(rand);
}
return rands;
} // 在不同的高度上输出验证码的每个字符
public void drawRands(Graphics g, char[] rands) {
g.setColor(Color.BLACK);
g.setFont(new Font(null, Font.ITALIC | Font.BOLD, 22));
g.drawString("" + rands[0], 5, 22);
g.drawString("" + rands[1], 24, 17);
g.drawString("" + rands[2], 39, 24);
g.drawString("" + rands[3], 56, 18);
System.out.println(rands);
} // 画背景并随机产生120个干扰点
public void drawBackground(Graphics g) {
g.setColor(new Color(0xDCDCDC));
g.fillRect(0, 0, WIDTH, HEIGHT);
for (int i = 0; i < 120; i++) {
int x = (int) (Math.random() * WIDTH);
int y = (int) (Math.random() * HEIGHT);
int red = (int) (Math.random() * 255);
int green = (int) (Math.random() * 255);
int blue = (int) (Math.random() * 255);
g.setColor(new Color(red, green, blue));
g.drawOval(x, y, 1, 0);
}
}}下面是jsp///////////////////////////////////////////////
<%@ page language="java" contentType="text/html; charset=GBK"
pageEncoding="GBK"%>
<%@page language="java" import="java.util.*"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<html>
<head>
<title>用户登陆</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">
<meta http-equiv="content-type" content="text/html; charset=GBK">
<link rel="stylesheet" href="../css/top.css" type="text/css">
</link>
<style type="text/css">
<!--
.style1 {
font-size: 16px
}
-->
</style>
<script type="text/javascript">
function refreshCc() //刷新图片
{
var ccImg = document.getElementById("checkCodeImg");
nowTime = new Date();
ccImg.src= "../CheckCodeServlet?e=" + nowTime.getTime();
}
function aa()
{
document.all.check_code.value="";
}
function check()
{
if(!isEmpty(f1.user,"用户名或邮箱") || !isEmpty(f1.pass,"密码")
|| !isEmpty(f1.check_code, "验证码"))
{
return false;
}
return true;
}
function isEmpty(obj,msg)
{
if(obj.value.length==0)
{
alert('请输入'+msg+'! ');
return false;
}
return true;
}
</script>
</head>
<BODY bgcolor="#769B72">
<table bgcolor="#FFFFFF" height="100%" width="900" align="center">
<tr>
<td> <div class="login-right">
<form action=" <%=path%>/LoginServlet" method="post" name="f1">
<div class="login-top"></div>
<div class="login-mid">
<DIV class="notice style1">用户登陆</DIV>
<div class="main">Email或用户昵称: <INPUT name="user" type="text"
class="login-input"> <br>
<span style="padding-left: 66px;"> 密码: </span> <INPUT name="pass"
type="password" class="login-input"> <br>
验证码: <input
name="check_code" type="text" onClick="aa()" maxlength="4"
class="login-input"> <br>
<img
src="<%=path %>../CheckCodeServlet" width="80" height="25"
align="absbottom" id="checkCodeImg"> <a
href="javascript:refreshCc();" target="_self" class="style8">换一张
</a><
<div class="login-dl"><INPUT name="dl" type="submit" value="登陆"
onclick="return check();" class="login-submit"></div>
</div> <div class="login-end">您还不是注册用户?</div>
<div align="right"><A href="register.html">创建一个新用户>> </A>
</div>
</form>
</div> </td>
</tr>
</table>
</BODY>
</HTML>
package com.test.validatecode;import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;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;public class CheckCodeServlet extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
private static int WIDTH = 80;
private static int HEIGHT = 25; public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("GBK");
response.setContentType("text/html;charset=GBK"); HttpSession session = request.getSession();
response.setContentType("images/jpg");
ServletOutputStream sos = response.getOutputStream(); // 设置浏览器不要缓存数据
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
// 创建内存图象并获得其图形上下文
BufferedImage image = new BufferedImage(WIDTH, HEIGHT,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
// 产生随机的认证码
char[] rands = this.generateCheckCode();
// 产生图像
this.drawBackground(g);
this.drawRands(g, rands);
// 结束图像的绘制过程,完成图像 g.dispose();
// 将图像输出到客户端
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ImageIO.write(image, "JPEG", bos);
byte[] buf = bos.toByteArray();
response.setContentLength(buf.length);
// 下面的语句也可写成:bos.writeTo(sos);
sos.write(buf);
bos.close();
sos.close(); // 将当前验证码存入到Session中
session.setAttribute("check_code", new String(rands));
// 直接使用下面的代码将有问题,Session对象必须在提交响应前获得
// request.getSession().setAttribute("check_code",new String(rands));
} // 定义验证码的字符表
public char[] generateCheckCode() {
String chars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
char[] rands = new char[4];
for (int i = 0; i < 4; i++) {
int rand = (int) (Math.random() * 62);
rands[i] = chars.charAt(rand);
}
return rands;
} // 在不同的高度上输出验证码的每个字符
public void drawRands(Graphics g, char[] rands) {
g.setColor(Color.BLACK);
g.setFont(new Font(null, Font.ITALIC | Font.BOLD, 22));
g.drawString("" + rands[0], 5, 22);
g.drawString("" + rands[1], 24, 17);
g.drawString("" + rands[2], 39, 24);
g.drawString("" + rands[3], 56, 18);
System.out.println(rands);
} // 画背景并随机产生120个干扰点
public void drawBackground(Graphics g) {
g.setColor(new Color(0xDCDCDC));
g.fillRect(0, 0, WIDTH, HEIGHT);
for (int i = 0; i < 120; i++) {
int x = (int) (Math.random() * WIDTH);
int y = (int) (Math.random() * HEIGHT);
int red = (int) (Math.random() * 255);
int green = (int) (Math.random() * 255);
int blue = (int) (Math.random() * 255);
g.setColor(new Color(red, green, blue));
g.drawOval(x, y, 1, 0);
}
}}下面是jsp///////////////////////////////////////////////
<%@ page language="java" contentType="text/html; charset=GBK"
pageEncoding="GBK"%>
<%@page language="java" import="java.util.*"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<html>
<head>
<title>用户登陆</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">
<meta http-equiv="content-type" content="text/html; charset=GBK">
<link rel="stylesheet" href="../css/top.css" type="text/css">
</link>
<style type="text/css">
<!--
.style1 {
font-size: 16px
}
-->
</style>
<script type="text/javascript">
function refreshCc() //刷新图片
{
var ccImg = document.getElementById("checkCodeImg");
nowTime = new Date();
ccImg.src= "../CheckCodeServlet?e=" + nowTime.getTime();
}
function aa()
{
document.all.check_code.value="";
}
function check()
{
if(!isEmpty(f1.user,"用户名或邮箱") || !isEmpty(f1.pass,"密码")
|| !isEmpty(f1.check_code, "验证码"))
{
return false;
}
return true;
}
function isEmpty(obj,msg)
{
if(obj.value.length==0)
{
alert('请输入'+msg+'! ');
return false;
}
return true;
}
</script>
</head>
<BODY bgcolor="#769B72">
<table bgcolor="#FFFFFF" height="100%" width="900" align="center">
<tr>
<td> <div class="login-right">
<form action=" <%=path%>/LoginServlet" method="post" name="f1">
<div class="login-top"></div>
<div class="login-mid">
<DIV class="notice style1">用户登陆</DIV>
<div class="main">Email或用户昵称: <INPUT name="user" type="text"
class="login-input"> <br>
<span style="padding-left: 66px;"> 密码: </span> <INPUT name="pass"
type="password" class="login-input"> <br>
验证码: <input
name="check_code" type="text" onClick="aa()" maxlength="4"
class="login-input"> <br>
<img
src="<%=path %>../CheckCodeServlet" width="80" height="25"
align="absbottom" id="checkCodeImg"> <a
href="javascript:refreshCc();" target="_self" class="style8">换一张
</a><
<div class="login-dl"><INPUT name="dl" type="submit" value="登陆"
onclick="return check();" class="login-submit"></div>
</div> <div class="login-end">您还不是注册用户?</div>
<div align="right"><A href="register.html">创建一个新用户>> </A>
</div>
</form>
</div> </td>
</tr>
</table>
</BODY>
</HTML>
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<servlet>
<servlet-name>CheckCodeServlet</servlet-name>
<servlet-class>
com.test.validatecode.CheckCodeServlet
</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>CheckCodeServlet</servlet-name>
<url-pattern>/CheckCodeServlet</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>10</session-timeout>
</session-config>
pageEncoding="GBK"%>
改成这样的
<%@ page language="java" contentType="image/JPEG; charset=GBK" pageEncoding="GBK"%>
看可以不?
src=" <%=path %>../CheckCodeServlet" width="80" height="25"
align="absbottom" id="checkCodeImg"> 路径对么?是不是加载的时候路径不对?
在这一句里,我试了一下,把CheckCodeServlet前面的../去掉就可以了,你也试试吧
你先把 <%=path %>输出来,
然后在结合 <%=path %>../CheckCodeServlet看是否是你想要的路径。。
<img src="CheckCodeServlet" width="80" height="25" align="absbottom" id="checkCodeImg"> 这样就OK了,这是直接请求servlet,还有,LZ注意一下,JSP页面为什么有basepath? 就是方便页面路径的,你在href,src等路径下面,不需要加绝对路径了,都是相对项目下。
看看我的这个吧 http://www.blogjava.net/jzone/articles/270724.html