如何用jsp实现验证码功能

lande163 2004-08-25 01:04:35

同标题,大侠们,给小弟帮个忙啊~~~

...全文

364 点赞收藏 8

写回复

8 条回复

切换为时间正序

当前发帖距今超过3年，不再开放新的回复

发表回复

lande163 2004-08-26

小弟我只试用了gjd111686的代码就好用了,但在此也对EdifierX表示感谢! frieblade同志也太滑稽了吧,把gjd111686的连接复制过来用~~~现在光出力的人不值钱了!

回复赞

lande163 2004-08-25

谢谢各位大侠,待小弟试过后,过来给分

回复赞

frieblade 2004-08-25

image.jsp

<%@ page contentType="image/jpeg"%>
<%@ page import="java.awt.*"%>
<%@ page import="java.awt.image.*"%>
<%@ page import="java.util.*"%>
<%@ page import="javax.imageio.*"%>
<%
//在内存中创建图象
int iWidth=130,iHeight=18;
BufferedImage image=new BufferedImage(iWidth,iHeight,BufferedImage.TYPE_INT_RGB);
//获取图形上下文
Graphics g=image.getGraphics();
//设定背景色
g.setColor(Color.white);
g.fillRect(0,0,iWidth,iHeight);
//画边框
g.setColor(Color.black);
g.drawRect(0,0,iWidth-1,iHeight-1);
//取随机产生的认证码(4位数字)
String rand=request.getParameter("Rand");
rand=rand.substring(0,rand.indexOf("."));
switch(rand.length())
{
case 1:rand="000"+rand;break;
case 2:rand="00"+rand;break;
case 3:rand="0"+rand;break;
default:rand=rand.substring(0,4);break;
}
//将认证码存入SESSION
session.setAttribute("Rand",rand);
//将认证码显示到图象中
g.setColor(Color.black);
g.setFont(new Font("Times New Roman",Font.PLAIN,18));
g.drawString(rand,10,15);
//随机产生88个干扰点,使图象中的认证码不易被其它程序探测到
Random random=new Random();
for(int iIndex=0;iIndex<88;iIndex++)
{
int x=random.nextInt(iWidth);
int y=random.nextInt(iHeight);
g.drawLine(x,y,x,y);
}
//图象生效
g.dispose();
//输出图象到页面
ImageIO.write(image,"JPEG",response.getOutputStream());
%>

输出时应用验证码

<script>document.write("<img border=0 src='/image.jsp?Rand="+Math.random()*10000+"'>");</script><br>
输认证码: <input name="Rand" maxlength=4 size="10"><br>

登录认证:

String Rand=request.getParameter("Rand");
String strRand=(String)session.getAttribute("Rand");
if(!strRand.equals(Rand))
{
//未通过;
}

回复赞

gjd111686 2004-08-25

http://blog.csdn.net/gjd111686/archive/2004/07/08/37113.aspx

回复赞

EdifierX 2004-08-25

這有一個代碼，參考一下吧！

import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.awt.*;
import java.awt.image.*;
import javax.imageio.*;

public class getImg extends HttpServlet {

private Color getRandColor(int fc,int bc){
//给定范围获得随机颜色
Random random = new Random();
if(fc>255) fc=255;
if(bc>255) bc=255;
int r=fc+random.nextInt(bc-fc);
int g=fc+random.nextInt(bc-fc);
int b=fc+random.nextInt(bc-fc);
return new Color(r,g,b);
}

//private Font mFont=new Font("宋体", Font.PLAIN,12);//设置字体
//处理post
public void doPost(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException {

doGet(request,response);
}
public void doGet(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException {

//设置页面不缓存
response.setHeader("Cache-Control","no-store");
response.setHeader("Pragma","no-cache");
response.setDateHeader("Expires",0);

// 在内存中创建图象
int width=60, height=20;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

// 获取图形上下文
Graphics g = image.getGraphics();

//生成随机类
Random random = new Random();

// 设定背景色
g.setColor(getRandColor(200,250));
g.fillRect(0, 0, width, height);

//设定字体
g.setFont(new Font("宋体",Font.BOLD,18));

//画边框
//g.setColor(new Color());
//g.drawRect(0,0,width-1,height-1);

// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
g.setColor(getRandColor(160,200));
for (int i=0;i<155;i++)
{
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(12);
int yl = random.nextInt(12);
g.drawLine(x,y,x+xl,y+yl);
}

// 取随机产生的认证码(4位数字)
String sRand="";
for (int i=0;i<4;i++){
String rand=String.valueOf(random.nextInt(10));
sRand+=rand;
// 将认证码显示到图象中
g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));//调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
g.drawString(rand,13*i+6,16);
}

// 将认证码存入SESSION
HttpSession session=request.getSession();
session.setAttribute("VerifyCode",sRand);

// 图象生效
g.dispose();
// 输出图象到页面
ImageIO.write(image, "JPEG", response.getOutputStream());

}

}

回复赞