JSP彩色驗證碼_JSP編程

來源:互聯網
上載者:User

    產生有4個隨機數字和雜亂背景的圖片,數字和背景顏色會改變,伺服器端重新整理(用history.go(-1)也會變)
原型參考ALIBABA  http://china.alibaba.com/member/showimage

產生驗證碼圖片的檔案-----image.jsp

<%@ page contentType="image/jpeg" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %>
<%!
Color getRandColor(int fc,int bc){//給定範圍獲得隨機顏色
        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);
        }
%>
<%
//設定頁面不緩衝
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);

// 在記憶體中建立圖象
int width=60, height=20;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

// 擷取圖形上下文
Graphics g = image.getGraphics();

//產生隨機類
Random random = new Random();

// 設定背景色
g.setColor(getRandColor(200,250));
g.fillRect(0, 0, width, height);

//設定字型
g.setFont(new Font("Times New Roman",Font.PLAIN,18));

//畫邊框
//g.setColor(new Color());
//g.drawRect(0,0,width-1,height-1);


// 隨機產生155條幹擾線,使圖象中的認證碼不易被其它程式探測到
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);
}

// 取隨機產生的認證碼(4位元字)
String sRand="";
for (int i=0;i<4;i++){
    String rand=String.valueOf(random.nextInt(10));
    sRand+=rand;
    // 將認證碼顯示到圖象中
    g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));//調用函數出來的顏色相同,可能是因為種子太接近,所以只能直接產生
    g.drawString(rand,13*i+6,16);
}

// 將認證碼存入SESSION
session.setAttribute("rand",sRand);


// 圖象生效
g.dispose();

// 輸出圖象到頁面
ImageIO.write(image, "JPEG", response.getOutputStream());


%>

---------------使用驗證碼圖片的檔案---------a.jsp------------------------------------

<%@ page contentType="text/html;charset=gb2312" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>認證碼輸入頁面</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>系統產生的認證碼:</td>
<td><img border=0 src="image.jsp"></td>
</tr>
<tr>
<td align=left>輸入上面的認證碼:</td>
<td><input type=text name=rand maxlength=4 value=""></td>
</tr>
<tr>
<td colspan=2 align=center><input type=submit value="提交檢測"></td>
</tr>
</form>
</body>
</html>

-----------------驗證的頁面----------check.jsp

<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<html>
<head>
<title>認證碼驗證頁面</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");
%>
系統產生的認證碼為: <%= rand %><br>
您輸入的認證碼為: <%= input %><br>
<br>
<%
  if (rand.equals(input)) {
%>
<font color=green>輸入相同,認證成功!</font>
<%
  } else {
%>
<font color=red>輸入不同,認證失敗!</font>
<%
  }
%>
</body>
</html>

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