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JSP彩色验证码源程序

2008-05-16 15:52 453 查看
 ---------------验证码图片文件---------image.jsp---------

<%@ page contentType="image/jpeg;charset=gbk" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %>
<%!
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);
        }
%>
<%
//设置页面不缓存
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","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("Times New Roman",Font.PLAIN,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
session.setAttribute("rand",sRand);

// 图象生效
g.dispose();

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

%>

 

---------------使用验证码图片的文件---------a.jsp---------

<%@ page contentType="text/html;charset=gb2312" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>认证码输入页面</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<META HTTP-EQUIV="Pragma" CONTENT="no-cache"> 
<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache"> 
<META HTTP-EQUIV="Expires" CONTENT="0"> 
</head>
<body>
<form method=post action="check.jsp">
<table>
<tr>
<td align=left>系统产生的认证码：</td>
<td><img border=0 src="image.jsp"></td>
</tr>
<tr>
<td align=left>输入上面的认证码：</td>
<td><input type=text name=rand maxlength=4 value=""></td>
</tr>
<tr>
<td colspan=2 align=center><input type=submit value="提交检测"></td>
</tr>

</table>
</form>
</body>
</html>

-----------------验证的页面----------check.jsp

<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<html>
<head>
<title>认证码验证页面</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<META HTTP-EQUIV="Pragma" CONTENT="no-cache"> 
<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache"> 
<META HTTP-EQUIV="Expires" CONTENT="0"> 
</head>

<body>
<% 
 String rand = (String)session.getAttribute("rand");
 String input = request.getParameter("rand");
%>
系统产生的认证码为： <%= rand %><br>
您输入的认证码为： <%= input %><br>
<br>
<%
  if (rand.equals(input)) {
%>
<font color=green>输入相同，认证成功！</font>
<%
  } else {
%>
<font color=red>输入不同，认证失败！</font>
<%
  }
%>
</body>
</html>
package com.java;

 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;
 import javax.servlet.http.HttpSession;

 public class AuthImg extends HttpServlet{

     // 设置图形验证码中字符串的字体和大小
     private Font mFont = new Font("Arial Black", Font.PLAIN, 16);

     public void init() throws ServletException {
         super.init();
     }

     // 生成随即颜色
     Color getRandColor(int fc, int bc) {
         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);
     }

     // 生成服务器响应的service方法
     public void service(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         // 组织生成页面内容被缓存，保证每次重新生成随机验证码
         response.setHeader("Pragma", "No-cache");
         response.setHeader("Cache-Control", "no-cache");
         response.setDateHeader("Expires", 0);
         // 指定 图形验证码大小
         int width = 100, height = 8;
         // 生成一张新图片
         BufferedImage image = new BufferedImage(width, height,
                 BufferedImage.TYPE_INT_RGB);
         // 在图片中绘制内容
         Graphics g = image.getGraphics();
         Random random = new Random();
         g.setColor(getRandColor(200, 250));
         g.fillRect(1, 1, width - 1, height - 1);
         g.setColor(new Color(102, 102, 102));
         g.setFont(mFont);
         // 随即生成线条，让图片看起来更加杂乱
         g.setColor(getRandColor(160, 200));
         for (int i = 0; i < 155; i++){
             int x1 = random.nextInt(width - 1);
             int y1 = random.nextInt(height - 1);
             int x2 = random.nextInt(6) + 1;
             int y2 = random.nextInt(12) + 1;
             g.drawLine(x1, y1, x2, y2);
         }
         // 随机生成线条，让图片看起来更杂乱
         for (int i = 0; i < 70; i++){
             int x1 = random.nextInt(width - 1);
             int y1 = random.nextInt(height - 1);
             int x2 = random.nextInt(6) + 1;
             int y2 = random.nextInt(12) + 1;
             g.drawLine(x1, y1, x2, y2);
         }
         // 读取变
9d0f
量，用于保存系统生成的随机字符串
         String sRand = "";
         for (int i = 0; i < 6; i++) {
             // 取得一个随机生成的字符
             String tmp = getRandomChar();
             sRand += tmp;
             // 将系统随机生成的字符添加到图形验证码图片上
             g.setColor(new Color(20 + random.nextInt(110), 20 + random
                     .nextInt(110), 20 + random.nextInt(110)));
             g.drawString(tmp, 15 * i + 10, 15);
         }
         // 取得用户Session
         HttpSession session = request.getSession(true);
         // 将系统随机生成的图形验证码添加到用户Session中
         session.setAttribute("rand", sRand);
         g.dispose();
         // 输出图形验证码图片
         ImageIO.write(image, "JPEG", response.getOutputStream());
     }

     private String getRandomChar() {
         int rand = (int) Math.round(Math.random() * 2);
         long itmp = 0;
         char ctmp = '' ;
         // 根据rand的值来决定是生成小写字母，大写字母和数字
         switch (rand) {
         // 生成大写字母
         case 1:
             itmp = Math.round(Math.random() * 25 + 65);
             ctmp = (char) itmp;
             return String.valueOf(ctmp);
             // 生成小写字母
         case 2:
             itmp = Math.round(Math.random() * 25 + 97);
             ctmp = (char) itmp;
             return String.valueOf(ctmp);
             // 生成数字
         default:
             itmp = Math.round(Math.random() * 9);
             return String.valueOf(itmp);
         }
     }
 }
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标签：  jsp random 图形 string session image
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