JSP彩色验证码

来源：互联网发布：广西科技大学尔雅网络编辑：程序博客网时间：2024/04/27 20:19

产生验证码图片的文件image.jsp

<%@ page contentType="image/jpeg" 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SESSIONsession.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></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>