Java生成一个带数字的验证码_java生成数字验证码

绝地灬酷狼 2022-11-06 12:59 161阅读 0赞

package cmr.Test;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics2D;

import java.awt.image.BufferedImage;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.servlet.\*;

import java.io.\*;

import javax.servlet.http.\*;

public class RandomCodeServlet extends HttpServlet\{    //验证码图片的宽度。    private int width=60;    //验证码图片的高度。    private int height=20;        protected void service(HttpServletRequest req, HttpServletResponse resp)                    throws ServletException, java.io.IOException    \{           BufferedImage buffImg=new BufferedImage(width,height,                                                BufferedImage.TYPE\_INT\_RGB);        Graphics2D g=buffImg.createGraphics();                //创建一个随机数生成器类。        Random random=new Random();                g.setColor(Color.WHITE);        g.fillRect(0,0,width,height);                //创建字体，字体的大小应该根据图片的高度来定。        Font font=new Font("Times New Roman",Font.PLAIN,18);        //设置字体。        g.setFont(font);                //画边框。        g.setColor(Color.BLACK);        g.drawRect(0,0,width-1,height-1);                //随机产生160条干扰线，使图象中的认证码不易被其它程序探测到。        g.setColor(Color.GRAY);        for (int i=0;i<10;i++)        \{            int x = random.nextInt(width);            int y = random.nextInt(height);            int xl = random.nextInt(12);            int yl = random.nextInt(12);            g.drawLine(x,y,x+xl,y+yl);        \}                        //randomCode用于保存随机产生的验证码，以便用户登录后进行验证。        StringBuffer randomCode=new StringBuffer();        int red=0,green=0,blue=0;                //随机产生4位数字的验证码。        for (int i=0;i<4;i++)        \{            //得到随机产生的验证码数字。            String strRand=String.valueOf(random.nextInt(10));                        //产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同。            red=random.nextInt(200);            green=random.nextInt(200);            blue=random.nextInt(200);                                  //产生随机高度 13至height之间            float imght = 0;            while(imght<=12)\{             imght = Float.parseFloat(String.valueOf(random.nextInt(height)));            \}            //用随机产生的颜色将验证码绘制到图像中。            g.setColor(new Color(red,green,blue));            g.drawString(strRand,13\*i+6,imght);                                    //将产生的四个随机数组合在一起。            randomCode.append(strRand);        \}        //将四位数字的验证码保存到Session中。        HttpSession session=req.getSession();        session.setAttribute("randomCode",randomCode.toString());                //禁止图像缓存。        resp.setHeader("Pragma","no-cache");        resp.setHeader("Cache-Control","no-cache");        resp.setDateHeader("Expires", 0);                resp.setContentType("image/jpeg");                //将图像输出到Servlet输出流中。        ServletOutputStream sos=resp.getOutputStream();        ImageIO.write(buffImg, "jpeg",sos);        sos.close();    \}\}