Rumah > Artikel > Java > Java中网页验证码功能的实现方法

Java中网页验证码功能的实现方法

黄舟asal: 2017-10-11 10:03:221615semak imbas

这篇文章主要为大家详细介绍了java实现网页验证码功能，具有一定的参考价值，感兴趣的小伙伴们可以参考一下

本文实例为大家分享了java网页验证码的实现代码，供大家参考，具体内容如下

Servlet:

package cn.bdqn.servlet;
 
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.font.ImageGraphicAttribute;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
 
 
@WebServlet(name = "Servlet",urlPatterns = "/yanCode")
public class Servlet extends HttpServlet {
 public void doPost(javax.servlet.http.HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  this.doGet(request,response);
 
 }
 
 public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 
  String s="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
  Random random = new Random();
  int width=500;
  int height=50;
  BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
  Graphics graphics = image.getGraphics();//相当于画笔
  //画背景
  graphics.setColor(Color.gray);
  graphics.fillRect(0,0,width,height);
  graphics.setColor(Color.black);
  for (int i = 0; i <4 ; i++) {
   int index = random.nextInt(s.length());
   String c = s.substring(index, index + 1);
   graphics.drawString(c,width/5*(i+1),15);
  }
 
  ImageIO.write(image,"jpg",response.getOutputStream());
 
 
 }
}

jsp:

<%--
 Created by IntelliJ IDEA.
 User: Administrator
 Date: 2017/10/10
 Time: 13:04
 To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
 <head>
 <title>验证码</title>
 </head>
 <body>
 <img src="yanCode" alt="验证码" style="width: 500px;height:50px">
 <input type="button" value="看不清,更换验证码" id="btn" onclick="changeCode();">
 
 <script type="text/javascript" src="js/jquery.min.js">
 </script>
 <script type="text/javascript" >
  function changeCode() {
   $("img").attr(&#39;src&#39;, &#39;yanCode?ts=&#39; + new Date().getTime());
 
  }
 </script>
 </body>
</html>

Atas ialah kandungan terperinci Java中网页验证码功能的实现方法. Untuk maklumat lanjut, sila ikut artikel berkaitan lain di laman web China PHP!

Kenyataan：

Kandungan artikel ini disumbangkan secara sukarela oleh netizen, dan hak cipta adalah milik pengarang asal. Laman web ini tidak memikul tanggungjawab undang-undang yang sepadan. Jika anda menemui sebarang kandungan yang disyaki plagiarisme atau pelanggaran, sila hubungi admin@php.cn

Artikel sebelumnya：Javaweb中jstl如何循环List中的Map数据的实例分析Artikel seterusnya：Java流操作对文件分割以及合并的过程

Artikel berkaitan

Lihat lagi