在servlet上实现生成验证码图片功能

忘是亡心i 2024-03-17 10:37 45阅读 0赞

## **在servlet上实现 生成验证码图片 功能** ##

### 代码： ###

package com.dong.servlet;
    
    /**
     * 生成验证码图片
     */
    
    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.IOException;
    import java.util.Random;
    
    @WebServlet("/CodeServlet")
    public class CodeServlet extends HttpServlet {
        private static final long serialVersionUID = 1L;
    
        public CodeServlet() {
        }
    
        @Override
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            this.doPost(request,response);
        }
    
        @Override
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            //设置字符集
            request.setCharacterEncoding("UTF-8");
            BufferedImage bufferedImage=new BufferedImage(80,25,BufferedImage.TYPE_INT_RGB);
            Graphics graphics=bufferedImage.getGraphics();
            graphics.fillRect(0,0,80,25);
    
            //验证码字符范围
            char[] ch="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789".toCharArray();
            Random random=new Random();
            int index;
            StringBuffer stringBuffer=new StringBuffer();// 保存字符串
            for(int i=0;i<4;i++){
                index=random.nextInt(ch.length);
                graphics.setColor(new Color(random.nextInt(225),random.nextInt(225),random.nextInt(225)));
                Font font=new Font("宋体",30,20);
                graphics.setFont(font);
                graphics.drawString(ch[index]+"",(i*20)+2,23);
                stringBuffer.append(ch[index]);
            }
            // 设置验证码中的干扰线
            for (int i=0;i<6;i++){
                // 随机获取干扰线的起点和终点
                int xStart=(int) (Math.random()*80);
                int yStart=(int) (Math.random()*25);
                int xEnd=(int) (Math.random()*80);
                int yEnd=(int) (Math.random()*25);
                graphics.getColor();
                graphics.drawLine(xStart,yStart,xEnd,yEnd);
            }
            HttpSession httpSession=request.getSession();// 保存到session
            httpSession.setAttribute("code",stringBuffer.toString());
            ImageIO.write(bufferedImage,"JPG",response.getOutputStream());// 写到输出流
        }
        private static Color interLine(int Low, int High){
            if (Low>225)
                Low=225;
            if (High > 255)
                High = 255;
            if (Low < 0)
                Low = 0;
            if (High < 0)
                High = 0;
            int interval=High-Low;
            int r=Low+(int) (Math.random()*interval);
            int g=Low+(int) (Math.random()*interval);
            int b=Low+(int) (Math.random()*interval);
            return new Color(r,g,b);
        }
    }

### 在浏览器上运行结果： ###

![3864f20dafd34f01aa0e34096c98be1f.png][]

[3864f20dafd34f01aa0e34096c98be1f.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/17/5fae9038ac854070af02da76747481dd.png