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<img border=0 src="image.jsp">,只需要把該代碼發(fā)在驗(yàn)證碼要顯示的區(qū)域就可以了）
<%@ page contentType="image/jpeg" import="Java.awt.*,Java.awt.image.*,Java.util.*,Javax.imageio.*" %>
<%!
public static String code="abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
Color getRandColor(int fc,int bc){//給定范圍獲得隨機(jī)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(shè)置頁(yè)面不緩存
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);
// 在內(nèi)存中創(chuàng)建圖象,設(shè)置圖片的顯示大小
int width=60, height=20;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// 獲取圖形上下文
Graphics g = image.getGraphics();
//生成隨機(jī)類
Random random = new Random();
// 設(shè)定背景色
g.setColor(getRandColor(200,250));
g.fillRect(0, 0, width, height);
//設(shè)定字體
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(jī)產(chǎn)生155條干擾線，使圖象中的認(rèn)證碼不易被其它程序探測(cè)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(jī)產(chǎn)生的認(rèn)證碼(由數(shù)字和字母組長(zhǎng)的)
String sRand="";
for (int i=0;i<4;i++){
int rand=random.nextInt(62);
sRand+=String.valueOf(code.charAt(rand));
// 將認(rèn)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(diào)用函數(shù)出來(lái)的顏色相同，可能是因?yàn)榉N子太接近，所以只能直接生成
g.drawString(String.valueOf(code.charAt(rand)),13*i+6,16);
}
// 將認(rèn)證碼存入SESSION
session.setAttribute("rand",sRand);
// 圖象生效
g.dispose();
// 輸出圖象到頁(yè)面
ImageIO.write(image, "JPEG", response.getOutputStream());
%>
.下面是一個(gè)test.jsp,來(lái)進(jìn)行驗(yàn)證碼生成的測(cè)試，然后交給check.jsp來(lái)處理
<%@ page contentType="text/html;charset=gb2312" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>認(rèn)證碼輸入頁(yè)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(tǒng)產(chǎn)生的認(rèn)證碼：</td>
<td><img border=0 src="image.jsp"></td>
</tr>
<tr>
<td align=left>輸入上面的認(rèn)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(cè)"></td>
</tr>
</form>
</body>
</html>
.下面是一個(gè)check.jsp
<%@ page contentType="text/html; charset=gb2312" language="Java" import="Java.sql.*" errorPage="" %>
<html>
<head>
<title>認(rèn)證碼驗(yàn)證頁(yè)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(tǒng)產(chǎn)生的認(rèn)證碼為： <%= rand %><br>
您輸入的認(rèn)證碼為： <%= input %><br>
<br>
<%
if (rand.equals(input)) {
%>
<font color=green>輸入相同，認(rèn)證成功！</font>
<%
} else {
%>
<font color=red>輸入不同，認(rèn)證失敗！</font>
<%
}
%>
</body>
</html>
jsp技術(shù)：jsp 生成驗(yàn)證碼代碼，轉(zhuǎn)載需保留來(lái)源！
鄭重聲明：本文版權(quán)歸原作者所有，轉(zhuǎn)載文章僅為傳播更多信息之目的，如作者信息標(biāo)記有誤，請(qǐng)第一時(shí)間聯(lián)系我們修改或刪除，多謝。
