谁给个JSP生成验证码的代码

  生成有4个随机数字和杂乱背景的图片，数字和背景颜色会改变，服务器端刷新（用history.go(-1)也会变）
    原型参考ALIBABA  http://china.alibaba.com/member/showimage
    产生验证码图片的文件-----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.setAttribute("rand",sRand);
    // 图象生效
    g.dispose();    // 输出图象到页面
    ImageIO.write(image, "JPEG", response.getOutputStream());
    %>---------------使用验证码图片的文件---------a.jsp------------------------------------
    <%@ page contentType="text/html;charset=gb2312" %>
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
    <head>
    <title>认证码输入页面</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>系统产生的认证码：</td>
    <td><img border=0 src="image.jsp"></td>
    </tr>
    <tr>
    <td align=left>输入上面的认证码：</td>
    <td><input type=text name=rand maxlength=4 value=""></td>
    </tr>
    <tr>
    <td colspan=2 align=center><input type=submit value="提交检测"></td>
    </tr>
    </form>
    </body>
    </html>    -----------------验证的页面----------check.jsp    <%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
    <html>
    <head>
    <title>认证码验证页面</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");
    %>
    系统产生的认证码为： <%= rand %><br>
    您输入的认证码为： <%= input %><br>
    <br>
    <%
      if (rand.equals(input)) {
    %>
    <font color=green>输入相同，认证成功！</font>
    <%
      } else {
    %>
    <font color=red>输入不同，认证失败！</font>
    <%
      }
    %>
    </body>
    </html>

可生成汉字的===============rand.jsp================================================
<%@ page language="java" pageEncoding="UTF-8"%>
<%@ page contentType="image/jpeg" import="java.awt.*,java.awt.image.*,java.util.*" %>
<%@ page autoFlush="false"  import="com.sun.image.codec.jpeg.*" %>
<%!
//生成随机颜色
Color getRandColor(Random random,int fc,int bc) {
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
// Set to expire far in the past.
    response.setHeader("Expires", "0");    // Set standard HTTP/1.1 no-cache headers.
    response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");    // Set standard HTTP/1.0 no-cache header.
    response.setHeader("Pragma", "no-cache");
// 设置图片的长宽
int width=160, height=30;
//设置备选汉字，剔除一些不雅的汉字
//汉字验证码
//String base = "\u7684\u4e00\u4e86\u662f\u6211\u4e0d\u5728\u4eba\u4eec\u6709\u6765\u4ed6\u8fd9\u4e0a\u7740\u4e2a\u5730\u5230\u5927\u91cc\u8bf4\u5c31\u53bb\u5b50\u5f97\u4e5f\u548c\u90a3\u8981\u4e0b\u770b\u5929\u65f6\u8fc7\u51fa\u5c0f\u4e48\u8d77\u4f60\u90fd\u628a\u597d\u8fd8\u591a\u6ca1\u4e3a\u53c8\u53ef\u5bb6\u5b66\u53ea\u4ee5\u4e3b\u4f1a\u6837\u5e74\u60f3\u751f\u540c\u8001\u4e2d\u5341\u4ece\u81ea\u9762\u524d\u5934\u9053\u5b83\u540e\u7136\u8d70\u5f88\u50cf\u89c1\u4e24\u7528\u5979\u56fd\u52a8\u8fdb\u6210\u56de\u4ec0\u8fb9\u4f5c\u5bf9\u5f00\u800c\u5df1\u4e9b\u73b0\u5c71\u6c11\u5019\u7ecf\u53d1\u5de5\u5411\u4e8b\u547d\u7ed9\u957f\u6c34\u51e0\u4e49\u4e09\u58f0\u4e8e\u9ad8\u624b\u77e5\u7406\u773c\u5fd7\u70b9\u5fc3\u6218\u4e8c\u95ee\u4f46\u8eab\u65b9\u5b9e\u5403\u505a\u53eb\u5f53\u4f4f\u542c\u9769\u6253\u5462\u771f\u5168\u624d\u56db\u5df2\u6240\u654c\u4e4b\u6700\u5149\u4ea7\u60c5\u8def\u5206\u603b\u6761\u767d\u8bdd\u4e1c\u5e2d\u6b21\u4eb2\u5982\u88ab\u82b1\u53e3\u653e\u513f\u5e38\u6c14\u4e94\u7b2c\u4f7f\u5199\u519b\u5427\u6587\u8fd0\u518d\u679c\u600e\u5b9a\u8bb8\u5feb\u660e\u884c\u56e0\u522b\u98de\u5916\u6811\u7269\u6d3b\u90e8\u95e8\u65e0\u5f80\u8239\u671b\u65b0\u5e26\u961f\u5148\u529b\u5b8c\u5374\u7ad9\u4ee3\u5458\u673a\u66f4\u4e5d\u60a8\u6bcf\u98ce\u7ea7\u8ddf\u7b11\u554a\u5b69\u4e07\u5c11\u76f4\u610f\u591c\u6bd4\u9636\u8fde\u8f66\u91cd\u4fbf\u6597\u9a6c\u54ea\u5316\u592a\u6307\u53d8\u793e\u4f3c\u58eb\u8005\u5e72\u77f3\u6ee1\u65e5\u51b3\u767e\u539f\u62ff\u7fa4\u7a76\u5404\u516d\u672c\u601d\u89e3\u7acb\u6cb3\u6751\u516b\u96be\u65e9\u8bba\u5417\u6839\u5171\u8ba9\u76f8\u7814\u4eca\u5176\u4e66\u5750\u63a5\u5e94\u5173\u4fe1\u89c9\u6b65\u53cd\u5904\u8bb0\u5c06\u5343\u627e\u4e89\u9886\u6216\u5e08\u7ed3\u5757\u8dd1\u8c01\u8349\u8d8a\u5b57\u52a0\u811a\u7d27\u7231\u7b49\u4e60\u9635\u6015\u6708\u9752\u534a\u706b\u6cd5\u9898\u5efa\u8d76\u4f4d\u5531\u6d77\u4e03\u5973\u4efb\u4ef6\u611f\u51c6\u5f20\u56e2\u5c4b\u79bb\u8272\u8138\u7247\u79d1\u5012\u775b\u5229\u4e16\u521a\u4e14\u7531\u9001\u5207\u661f\u5bfc\u665a\u8868\u591f\u6574\u8ba4\u54cd\u96ea\u6d41\u672a\u573a\u8be5\u5e76\u5e95\u6df1\u523b\u5e73\u4f1f\u5fd9\u63d0\u786e\u8fd1\u4eae\u8f7b\u8bb2\u519c\u53e4\u9ed1\u544a\u754c\u62c9\u540d\u5440\u571f\u6e05\u9633\u7167\u529e\u53f2\u6539\u5386\u8f6c\u753b\u9020\u5634\u6b64\u6cbb\u5317\u5fc5\u670d\u96e8\u7a7f\u5185\u8bc6\u9a8c\u4f20\u4e1a\u83dc\u722c\u7761\u5174\u5f62\u91cf\u54b1\u89c2\u82e6\u4f53\u4f17\u901a\u51b2\u5408\u7834\u53cb\u5ea6\u672f\u996d\u516c\u65c1\u623f\u6781\u5357\u67aa\u8bfb\u6c99\u5c81\u7ebf\u91ce\u575a\u7a7a\u6536\u7b97\u81f3\u653f\u57ce\u52b3\u843d\u94b1\u7279\u56f4\u5f1f\u80dc\u6559\u70ed\u5c55\u5305\u6b4c\u7c7b\u6e10\u5f3a\u6570\u4e61\u547c\u6027\u97f3\u7b54\u54e5\u9645\u65e7\u795e\u5ea7\u7ae0\u5e2e\u5566\u53d7\u7cfb\u4ee4\u8df3\u975e\u4f55\u725b\u53d6\u5165\u5cb8\u6562\u6389\u5ffd\u79cd\u88c5\u9876\u6025\u6797\u505c\u606f\u53e5\u533a\u8863\u822c\u62a5\u53f6\u538b\u6162\u53d4\u80cc\u7ec6";
//英文字符和数字混合验证码（没有数字‘0’，没有英文字母‘o,O’）
String base = "123456789abcdefghijklmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ";
int length = base.length();
//创建内存图像
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// 获取图形上下文
Graphics g = image.getGraphics();

//创建随机类的实例
Random random = new Random();

// 设定图像背景色(因为是做背景，所以偏淡)
g.setColor(getRandColor(random,200,250));
g.fillRect(0, 0, width, height);
//备选字体
String[] fontTypes = {"\u5b8b\u4f53","\u65b0\u5b8b\u4f53","\u9ed1\u4f53","\u6977\u4f53","\u96b6\u4e66"};
int fontTypesLength = fontTypes.length;
//在图片背景上增加噪点
g.setColor(getRandColor(random,160,200));
g.setFont(new Font("Times New Roman",Font.PLAIN,14));
for (int i=0;i<6;i++) {
     g.drawString("*********************************************",0,5*(i+2));
} //取随机产生的认证码(5个汉字)
String sRand="";
for (int i=0;i<5;i++) {
     int start = random.nextInt(length);
     String rand=base.substring(start,start+1);
     sRand+=rand;

     //设置字体的颜色
     g.setColor(getRandColor(random,10,150));
     //设置字体
     g.setFont(new Font(fontTypes[random.nextInt(fontTypesLength)],Font.BOLD,18 + random.nextInt(6)));
     //将此汉字画到图片上
g.drawString(rand,24*i+ 10 + random.nextInt(8),24);
} //将认证码存入session
session.setAttribute("rand",sRand); g.dispose(); //输出图象到页面
ServletOutputStream outStream = response.getOutputStream();
JPEGImageEncoder encoder =JPEGCodec.createJPEGEncoder(outStream);
encoder.encode(image);
outStream.flush();
outStream.close();
out.clear();
out = pageContext.pushBody();
%> ============调用代码========================
<img src="rand.jsp" id="random" hspace="">

封装在Servlet中可以重复使用
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class CheckCodeServlet extends HttpServlet {
private static int WIDTH = 80;
private static int HEIGHT = 25;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("GBK");
response.setContentType("text/html;charset=GBK");
HttpSession session = request.getSession();
response.setContentType("image/jpeg");
ServletOutputStream sos = response.getOutputStream();
//设置浏览器不要缓存数据
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);
//创建内存图象并获得其图形上下文
BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
//产生随机的认证码
char [] rands = this.generateCheckCode();
//产生图像
this.drawBackground(g);
this.drawRands(g,rands);
//结束图像的绘制过程，完成图像
g.dispose();
//将图像输出到客户端
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ImageIO.write(image, "JPEG", bos);
byte [] buf = bos.toByteArray();
response.setContentLength(buf.length);
//下面的语句也可写成：bos.writeTo(sos);
sos.write(buf);
bos.close();
sos.close();
//将当前验证码存入到Session中
session.setAttribute("check_code",new String(rands));
//直接使用下面的代码将有问题，Session对象必须在提交响应前获得
//request.getSession().setAttribute("check_code",new String(rands));
}
//定义验证码的字符表
public char [] generateCheckCode()
{
String chars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
char [] rands = new char[4];
for(int i=0; i<4; i++)
{
int rand = (int)(Math.random() * 62);
rands[i] = chars.charAt(rand);
}
return rands;
}
//在不同的高度上输出验证码的每个字符
public void drawRands(Graphics g , char [] rands)
{
g.setColor(Color.BLACK);
g.setFont(new Font(null,Font.ITALIC|Font.BOLD,22));
g.drawString("" + rands[0],5,22);
g.drawString("" + rands[1],24,17);
g.drawString("" + rands[2],39,24);
g.drawString("" + rands[3],56,18);
System.out.println(rands);
}
//画背景并随机产生120个干扰点
public void drawBackground(Graphics g)
{
g.setColor(new Color(0xDCDCDC));
g.fillRect(0, 0, WIDTH, HEIGHT);
for(int i=0; i<120; i++)
{
int x = (int)(Math.random() * WIDTH);
int y = (int)(Math.random() * HEIGHT);
int red = (int)(Math.random() * 255);
int green = (int)(Math.random() * 255);
int blue = (int)(Math.random() * 255);
g.setColor(new Color(red,green,blue));
g.drawOval(x,y,1,0);
}
}
}
=============================
jsp页面：<%@ page language="java" import="java.util.*" pageEncoding="GBK"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
   + request.getServerName() + ":" + request.getServerPort()
   + path + "/";
%>
<html>
<head>
  <title>用户登陆</title>
  <meta http-equiv="pragma" content="no-cache">
  <meta http-equiv="cache-control" content="no-cache">
  <meta http-equiv="expires" content="0">
  <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
  <meta http-equiv="description" content="this is my page">
  <meta http-equiv="content-type" content="text/html; charset=GBK">
  <link rel="stylesheet" href="../css/top.css" type="text/css"></link>
  <style type="text/css">

  </style>
<script type="text/javascript">

     function refreshCc()  //刷新图片
    {
          var ccImg = document.getElementById("checkCodeImg");
       nowTime = new Date();
      ccImg.src= "../CheckCodeServlet?e=" + nowTime.getTime();
   }

   function aa()
   {
     document.all.check_code.value="";
   }

   function check()
   {
      if(!isEmpty(f1.user,"用户名或邮箱") || !isEmpty(f1.pass,"密码")
       || !isEmpty(f1.check_code, "验证码"))
       {
         return false;
       }
       return  true;
   }
    function isEmpty(obj,msg)
    {
        if(obj.value.length==0)
        {
            alert('请输入'+msg+'！ ');
         return false;
        }
        return true;
    }


  </script>
</head>
<BODY bgcolor="#769B72">
  <table bgcolor="#FFFFFF" height="100%" width="900" align="center">
   <tr>
    <td>

       <div class="login-right">
        <form action="<%=path%>/LoginServlet" method="post" name ="f1">
         <div class="login-top"></div>
         <div class="login-mid">
          <DIV class="notice style1">
           用户登陆
          </DIV>
          <div class="main">
           Email或用户昵称： <INPUT name="user"    type="text" class="login-input">
           <br>
           <span style="padding-left:66px;"> 密码：</span>
           <INPUT name="pass" type="password"  class="login-input">
           <br>
                    验证码：
           <input name="check_code" type="text" onClick="aa()"  maxlength="4" class="login-input">
           <br>
                  
           <img src="<%=path %>/CheckCodeServlet" width="80" height="25" align="absbottom" id="checkCodeImg">
           <a href="javascript:refreshCc();" target="_self" class="style8">换一张</a>
           <div class="login-dl">
            <INPUT name="dl" type="submit" value= "登陆" onclick="return check();" class="login-submit">
           </div>
          </div>
          <div class="login-end">
           您还不是注册用户？
          </div>
          <div align="right"> <A href="register.html">创建一个新用户>></A>  
          </div>
        </form>
       </div>

      </div>
     </div>


    </td>
   </tr>
  </table>
</BODY>
</HTML>

response.setContentType("image/jpeg"); 这个咋弄的，我也照着弄了，可以页面图片没有显示出来，？我的WebContent有个image这个文件夹，下面有jpg类型的图片

调试易

谁给个JSP生成验证码的代码

解决方案 »