jsp验证码怎么写( 二 ) _验证码

<10; i++){ int x = rand.nextInt(width); int y = rand.nextInt(height); g.drawOval(x,y,1,1)； } //释放图形上下文 g.dispose(); try{ //输出图形到页面 ImageIO.write(image, "JPEG", os); }catch (IOException e){ return ""; } return strEnsure; } } makeCertPic.jsp页面用于调用生成验证码图片的JavaBean，并在客户端显示，源代码如下：<%@page contentType="image/jpeg" %><%@page language="java" pageEncoding="utf-8"%><% String str = image.getCertPic(0,0,response.getOutputStream（)）； //将验证码存入session中 session.setAttribute("certCode",str)；%> 下边是登录页面：<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><meta ; charset=UTF-8">验证码测试登录页面 <body> 。
4. Jsp验证码怎么写 <tr>
<td valign="middle" align="right">
验证码：
<img id="num" src="http://www.xuexi88.com/zhishi/checkCode" />
<a href="javascript:;"
【jsp验证码怎么写】onclick="document.getElementById('num').src = 'http://www.xuexi88.com/zhishi/checkCode?'+(new Date()).getTime()">；换一张</a>
</td>
<td valign="middle" align="left">
<input type="text" class="inputgri" name="number" />
</td>
</tr>
你是不是不知道那个图片怎么换啊？我当时也找了好多改变图片的方法，利用系统时间是最好的解决办法
5. 在java页面上,用jsp,怎样写一个验证码 //验证码生成页面<%@ page language="java" import="java.util.*" pageEncoding="GBK"%><%@ page import = " java.awt.*,java.awt.image.*,javax.imageio.* " %> <%@ 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 i = 0 ;i < 4 ;i ++ ){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 * i + 6 , 16 );}session.setAttribute("vcode" ,sRand);g.dispose();ImageIO.write(image, "jpg" ,os);os.flush();os.close();os = null ;response.flushBuffer();out.clear();out = pageContext.pushBody();}catch (IllegalStateException e){System.out.println(e.getMessage());e.printStackTrace（)；} %>//验证码使用页面<%@ page language="java" import="java.util.*" pageEncoding="gbk"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%> My JSP 'index.jsp' starting page <meta > 。
6. 如何用JSP生成验证码 <%@ page language="java" contentType="text/html; charset=GBK" pageEncoding="GBK"%><%@ page import="java.awt.*" %><%@ page import="java.awt.image.*" %><%@ page import="java.util.*" %><%@ page import="javax.imageio.*" %><%! Color getRandColor(int fc,int bc){ Random r = new Random(); if(fc > 255) fc = 255; if(bc > 255) bc = 255; int red = fc + r.nextInt(bc - fc); int green = fc + r.nextInt(bc - fc); int blue = fc + r.nextInt(bc - fc); return new Color(red,green,blue)； }%><% //设置页面不缓存 response.setHeader("Pragma", "No-cache"); response.setHeader("Cache-Control", "no-cache"); response.setDateHeader("Expires", 0)；//下面开始了--生成图像 Random r = new Random(); int width = 60,height = 20; BufferedImage pic = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); Graphics gc = pic.getGraphics(); gc.setColor(getRandColor(200,250)); gc.fillRect(0, 0, width, height); gc.setFont(new Font("Times New Roman",Font.PLAIN,18)); gc.setColor(getRandColor(160,200)); for(int i=0;i