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  • javaee添加验证码

    package com.zh.code;
    
    import java.awt.Color;
    import java.awt.Font;
    import java.awt.Graphics;
    import java.awt.image.BufferStrategy;
    import java.awt.image.BufferedImage;
    import java.io.IOException;
    import java.io.PrintWriter;
    import java.util.Random;
    
    import javax.imageio.ImageIO;
    import javax.jms.Session;
    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 CreateCode extends HttpServlet {
    
    
        public void doGet(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
            
            response.setContentType("text/html");
            response.setHeader("Content", "image/jpeg");
            //7.禁止浏览器缓存 随机图片
            response.setDateHeader("Expires", -1);
            response.setHeader("Cache-Control", "no-cache");
            response.setHeader("Pragma", "no-cache");
            
            //1.创建一个图片的内在 bufferedImage
            //BufferedImage image=new BufferedImage(80, 30, BufferedImage.TYPE_INT_ARGB);
            BufferedImage image=new BufferedImage(50,30 , BufferedImage.TYPE_INT_BGR);
            //        
            //2.得到image的画笔
            Graphics g=image.getGraphics();
            g.setColor(Color.CYAN);
            g.fillRect(0, 0, 50, 30);
            //在上面写数字 
            g.setColor(Color.BLACK);
            g.setFont(new Font(null,Font.BOLD,20));
            String num=this.getCodeNum();
            g.drawString(num, 0, 20);
            
            
            //把得到的 验证码存在session中
            request.getSession().setAttribute("code", num);
            
            //3.图片发送
             ImageIO.write(image, "jpg", response.getOutputStream());
        }
        //返回的随机数据字符串
        public String getCodeNum(){
            Random randow=new Random();
            String num=randow.nextInt(9999)+"";
            StringBuffer stringBuffer=new StringBuffer("");
            for(int i=0;i<4-num.length();i++){
                stringBuffer.append("0");
            }
            num+=stringBuffer;
            return num;
        }
    
        /**
         * The doPost method of the servlet. <br>
         *
         * This method is called when a form has its tag value method equals to post.
         * 
         * @param request the request send by the client to the server
         * @param response the response send by the server to the client
         * @throws ServletException if an error occurred
         * @throws IOException if an error occurred
         */
        public void doPost(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
    
            response.setContentType("text/html");
            this.doGet(request, response);
            
        }
    
    }
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  • 原文地址:https://www.cnblogs.com/shaoshao/p/3421163.html
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