package com.kuang.servlet;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
public class ImageServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//设置3秒自动刷新
resp.setHeader("refresh", "3");
BufferedImage bufferedImage=new BufferedImage(80, 20, BufferedImage.TYPE_INT_RGB);
Graphics2D graphics=(Graphics2D)bufferedImage.getGraphics();//笔\
graphics.setColor(Color.white);
graphics.fillRect(0, 0, 80, 20);//填充白色背景
//给图片写数据
graphics.setColor(Color.BLUE);
graphics.setFont(new Font(null, Font.BOLD, 20));
graphics.drawString(makeNum(), 0, 20);
//告诉浏览器这个请求用图片的方式打开
resp.setContentType("image/jpeg");
//不缓存
resp.setDateHeader("expires",-1);
resp.setHeader("Cache-Control", "no-cache");
resp.setHeader("Pragma","no-cache");
//把图片写给浏览器
boolean write= ImageIO.write(bufferedImage, "jpg", resp.getOutputStream());
}
private String makeNum(){
Random random=new Random();
String num=random.nextInt(9999999)+"";
StringBuffer sb=new StringBuffer();
for(int i=0;i<7-num.length();i++){
sb.append("0");
}
num=sb.toString()+num;
return num;
}
}
用JAVA写一个自动刷新验证码
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转载自blog.csdn.net/weixin_41066584/article/details/109864010
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