日期:2014-05-17  浏览次数:20643 次

验证码问题___为什么在火狐浏览器上能运行而IE和360等浏览器却不能成功运行
我在调试一个验证码生成和验证的jsp页面时发现代码在firefox上能够成功运行,而在ie和360等上面却不能成功运行

代码:
//-----------------------------------------------------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SESSION
session.removeAttribute("rand");
session.setAttribute("rand",sRand);
// 图象生效
g.dispose();

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


//--------------------------------------------Register.jsp------------------------------------------------------
<%@ page language="java" contentType="text/html; charset=gb2312"
import="java.util.*"%>
<%@ page import="javax.swing.*" %>
<%@ page import="java.sql.*" %>
<html>
<head>
<title>用户注册</title>
</head>
  <meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">  
  <script language="javascript">
<!-->本函数用于用于单击检测时,获取用户名输入框的值。并把获取的值传送到UserQuery.jsp页面中进行用户名是否存在的验证<-->
function query(){
var userid = document.getElementById("userid");
var queryhref = document.getElementById("useridquery");
queryhref.href = "UserQuery.jsp?userid="+userid.value;
}
function validateCodeWroung(){
alert("验证码输入有误!");
}
function validateCodeRight(){
alert("验证码输入正确!");
}
</script>
  <%
String validateCode = (String)session.getAttribute("rand");