点击验证码无刷新重新加载验证码图片

来源：互联网发布：网络电话卡有哪些编辑：程序博客网时间：2024/05/22 02:23

点击验证码无刷新重新加载验证码图片

生成验证码图片的image.jsp：

Java代码  
<%@page contentType="image/jpeg;charset=utf-8"%>  
<%@page import="java.util.*,java.awt.*,java.awt.image.*,javax.imageio.*" %>  
<%@ page import="java.io.OutputStream" %>  
<html>  
 <body>  
  <%!   
   Color getRandColor(int fc,int bc)  
   {  
    Random rd=new Random();  
    if(fc>255) fc=255;  
    if(bc>255) bc=255;  
    int red=fc+rd.nextInt(bc-fc);  
    int green=fc+rd.nextInt(bc-fc);  
    int blue=fc+rd.nextInt(bc-fc);  
    return new Color(red,green,blue);  
   }  
   %>  
   <%   
    Random r=new Random();  
    response.addHeader("Pragma","No-cache");  
    response.addHeader("Cache-Control","no-cache");  
    response.addDateHeader("expires",0);     
    int width=90;  
    int height=23;  
   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);  
   String[] rNum ={"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f",  
      "g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w",  
      "x","y","z","A","B","C","D","E","F","G","H","I","J","K","L","M","N",  
      "O","P","Q","R","S","T","U","V","W","X","Y","Z"};  
   int[] style = {Font.PLAIN,Font.BOLD,Font.ITALIC,Font.PLAIN+Font.BOLD,  
     Font.BOLD+Font.ITALIC,Font.PLAIN+Font.ITALIC,Font.PLAIN+Font.BOLD+Font.ITALIC};  
   gc.setColor(Color.WHITE);  
   gc.drawLine(0,30,90,10);  
   gc.setColor(getRandColor(160,200));  
   for (int i=0;i<50;i++)      
   {  
    int x = r.nextInt(width);      
    int y = r.nextInt(height);      
    int xl = r.nextInt(10);      
    int yl = r.nextInt(10);      
    gc.drawLine(x,y,x+xl,y+yl);      
   }  
   gc.setColor(getRandColor(60,150));  
   String rt = "";  
   for(int i=0;i<4;i++){  
    String temp = rNum[r.nextInt(62)];  
    rt = rt+temp;  
    gc.setFont(new Font("Times New Roman",style[r.nextInt(7)],15));  
    gc.drawString(temp,5+i*15+r.nextInt(10),10+r.nextInt(10));  
   }  
   gc.dispose();  
   session.setAttribute("randNum",rt);     
   OutputStream os=response.getOutputStream();  
   ImageIO.write(pic,"JPEG",os);  
   System.out.println("当前验证码为:"+session.getAttribute("randNum"));  
   os.flush();  
   os.close();  
   os=null;  
   response.flushBuffer();  
   out.clear();  
   out = pageContext.pushBody();  
    %>  
 </body>  
</html>  

实现无刷新重新加载步骤：

1.在需要使用验证码的网页文件头部加上js代码：

写道

2.然后再验证码图片里面写onclick呼出上面的函数重新加载：

写道

3.两个文件在同一目录下，点击图片即可实现验证码重新加载

参考：http://zhidao.baidu.com/question/97875728.html
http://www.itwis.com/html/programme/javascript/20080416/1296.html

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