验证码字库.............................

好像都是自己画的，不管是asp还是jsp

我们CSDN 这个验证码是怎么做的

这个图片都是自己画的吧，上边的数字也是随机生成的
上周我们老师教我们在jsp中用java代码画，在页面中用<img>标签，在该标签的src属性中放生成图片的那个jsp页面地址就是了
注:我新手，说错了请包含^_^

有这样的库吗？我是没听过的。
这是我用的：（楼主，这个很好的实现了验证码的功能，自己看看代码吧）
1.首先写servlet    VerifyImage.java
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class VerifyImage extends HttpServlet {
private static final long serialVersionUID = 3262322998876293078L;
public void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
   response.setContentType("image/jpeg");
   response.setHeader("Pragma", "No-cache");
   response.setHeader("Cache-Control", "no-cache");
   response.setDateHeader("Expires", 0);
   HttpSession session = request.getSession();
   // 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("VerifyCode", sRand);
   // 图象生效
   g.dispose();
   // 输出图象到页面
   ImageIO.write(image, "JPEG", response.getOutputStream());
   //JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(res.getOutputStream());
   //encoder.encode(image);
}
// 给定范围获得随机颜色
private Color getRandColor(int fc, int bc) {
   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);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
   doGet(request, response);
}
}
2.配置web.xml
<?xml version="1.0" encoding="gbk"?>
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>
    <description>This is the description of verify image</description>
    <display-name>verify image</display-name>
    <servlet-name>VerifyImage</servlet-name>
    <servlet-class>com.testajax.VerifyImage</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>VerifyImage</servlet-name>
    <url-pattern>/servlet/VerifyImage</url-pattern>
</servlet-mapping>
</web-app>
3.写JSP页面   showverifycode.jsp
<%@ page language="java" contentType="text/html;charset=gbk" pageEncoding="gbk"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
   <title>Ajax+jsp实现无刷新验证码</title>
   <script type="text/javascript">
    var request=false ;
      try {
        request = new XMLHttpRequest();
       } catch (trymicrosoft) {
        try {
           request = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (othermicrosoft) {
           try {
             request = new ActiveXObject("Microsoft.XMLHTTP");
           } catch (failed) {
             request = false;
           }
        }
      }
      if (!request)
        alert("Error initializing XMLHttpRequest!");

    function reloadImage(){
    var url="/ajax/servlet/VerifyImage";
    request.open("GET",url,true);
    request.onreadystatechange=updatePage;
    request.send(null);
    }

    function updatePage(){
            if (request.readyState == 4)
            if (request.status == 200)
                document.getElementById("pic").src="/ajax/servlet/VerifyImage";
            else if (request.status == 404)
                alert("Request URL does not exist");
            else
                alert("Error: status code is " + request.status);
    }

    </script>
</head>
<body>
   Ajax+jsp实现无刷新验证码
   <br>
   <img id="pic" src="/ajax/servlet/VerifyImage" onclick="reloadImage()"/><span">看不清，换一张</span>
</body>
</html>

调试易

验证码字库.............................

解决方案 »