验证码实例

来源：互联网发布：java培训课程体系编辑：程序博客网时间：2024/06/03 16:20

 package com.lljr.servlet; 2  3 import java.awt.Color; 4 import java.awt.Font; 5 import java.awt.Graphics; 6 import java.awt.image.BufferedImage; 7 import java.io.IOException; 8 import java.util.Random; 9 10 import javax.imageio.ImageIO;11 import javax.servlet.ServletException;12 import javax.servlet.http.HttpServlet;13 import javax.servlet.http.HttpServletRequest;14 import javax.servlet.http.HttpServletResponse;15 import javax.servlet.http.HttpSession;16 /**17  * 验证码18  * @AUTHER LiuLonglong19  * @Motto Goals determine what you are going to be.20  * @URL http://www.cnblogs.com/mvilplss/21  */22 public class VerificationServlet extends HttpServlet {23 24     private static final long serialVersionUID = 1L;25     // 设置字母的大小,大小26     private Font mFont = new Font("宋体", Font.BOLD, 28);27 28     @Override29     protected void service(HttpServletRequest request,30             HttpServletResponse response) throws ServletException, IOException {31         // 创建画板缓冲区32         int width = 132;33         int height = 45;34         BufferedImage img = new BufferedImage(width, height,35                 BufferedImage.TYPE_INT_RGB);36         // 获取画板37         Graphics g = img.getGraphics();38         g.setColor(new Color(255, 255, 255));39         g.fillRect(0, 0, width, height);// 填充颜色40         g.setColor(new Color(102, 102, 102));41         g.drawRect(0, 0, width - 1, height - 1);// 画出边框42         // 画随机线43         Random random = new Random();44         for (int i = 0; i < 15; i++) {45             int x = random.nextInt(width - 1);46             int y = random.nextInt(height - 1);47             int xl = random.nextInt(12) + 1;48             int yl = random.nextInt(48) + 1;49             g.setColor(new Color(random.nextInt(255), random.nextInt(5), random50                     .nextInt(10)));51             g.drawLine(x, y, x + xl, y + yl);52         }53         // 画上字符串54         g.setColor(new Color(25, 11, 222));55         g.setFont(mFont);56         String[] chars = { "1", "2", "3", "4", "5", "6", "7", "8", "9", "0",57                 "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l",58                 "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "s",59                 "y", "z", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J",60                 "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V",61                 "W", "S", "Y", "Z" };62         String randomString = "";63         for (int i = 0; i < 6; i++) {64             int index = random.nextInt(62);65             int rc = random.nextInt(256);66             int gc = random.nextInt(256);67             int bc = random.nextInt(25);68             g.setColor(new Color(rc, gc, bc));69             g.drawString(chars[index], 21 * i + 5, 30);70             randomString += chars[index];71         }72         g.dispose();73         g.dispose();74         HttpSession session = request.getSession();75         session.setAttribute("system_verification_code", randomString);76         ImageIO.write(img, "JPEG", response.getOutputStream());77     }78 79 }

页面请求验证码：

刷新按钮js：

function _verification_reload(){
$("#_verification").attr("src","${basePath}/verificationServlet.servlet?a="+Math.random());
}

实现效果：

如果部分浏览器显示为一堆乱码时，请加上以下代码来设置浏览器接受的形式：

response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
response.setContentType("image/jpeg");

【来源】http://www.cnblogs.com/mvilplss/

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