Javaweb----图形验证码登录

小灰灰 2024-03-16 13:27 24阅读 0赞

**目录**

Javaweb----图形验证码登录

代码：

运行结果：

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## Javaweb----图形验证码登录 ##

#### 代码： ####

package com.dong.servlet;
    
    import javax.imageio.ImageIO;
    import javax.servlet.*;
    import javax.servlet.http.*;
    import javax.servlet.annotation.*;
    import java.awt.*;
    import java.awt.image.BufferedImage;
    import java.io.ByteArrayOutputStream;
    import java.io.IOException;
    
    @WebServlet( "/checkcode")
    public class CheckCode extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            response.setContentType("image/jpeg");
    
            HttpSession session=request.getSession();
            int with=60;
            int height=20;
    
            //设置浏览器不要缓存此图片
            response.setHeader("Pragma","No-cache");
            response.setHeader("Cache-Control","no-cache");
            response.setDateHeader("Expires",0);
    
            //创建内存图像并获得其图像的上下文
            BufferedImage image =new BufferedImage(with,height,BufferedImage.TYPE_INT_RGB);
            Graphics graphics=image.getGraphics();
    
            //随机产生验证码
            //定义验证码的字符表
            String chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
            char[] rands=new char[4];
            for (int i=0;i<4;i++){
                int rand=(int) (Math.random()*36);
                rands[i]=chars.charAt(rand);
            }
    
            //产生图像
            //画背景
            graphics.setColor(new Color(0xDCDCDC));
            graphics.fillRect(0,0,with,height);
    
            //随机产生120个干扰点
            for (int i=0;i<120;i+