登录验证码实例，支持鼠标点击切换验证码
1.首先是生产验证码的jsp页面：<%@ page import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" pageEncoding="utf-8"%><%@ page import="java.io.OutputStream" %> <%!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);}%><%try{response.setHeader("Pragma","No-cache");response.setHeader("Cache-Control","no-cache");response.setDateHeader("Expires", 0);int width=60, height=20;BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);OutputStream os=response.getOutputStream();Graphics g = image.getGraphics();Random random = new Random();g.setColor(getRandColor(200,250));g.fillRect(0, 0, width, height);g.setFont(new Font("Times New Roman",Font.PLAIN,18));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);}String sRand="";for (int j=0;j<4;j++){String rand=String.valueOf(random.nextInt(10));sRand+=rand;g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));g.drawString(rand,13*j+6,16);}session.setAttribute("rand",sRand);g.dispose();ImageIO.write(image, "JPEG",os);os.flush();os.close();os=null;response.flushBuffer();out.clear();out = pageContext.pushBody();}catch(IllegalStateException e){System.out.println(e.getMessage());e.printStackTrace();}%>
2.登录页面的相关代码：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%@ include file="/pages/commons/taglibs.jsp"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head> <title></title> <script type="text/javascript">/** * 换验证码图片 */ function change(img) { img.src = '${ctx}/pages/commons/image.jsp?seed=' + Math.random(); } </script></head> <body >验证码<imgborder=0 src="${ctx}/pages/commons/image.jsp"></a></body></html>
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