使用servlet+awt画笔绘制简易response验证码

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 {
        //设置浏览器三秒自动刷新
        resp.setHeader("refresh","3");
        //在内存中创建一个图片
        BufferedImage image = new BufferedImage(100, 20, BufferedImage.TYPE_3BYTE_BGR);
        //得到图片
        Graphics2D G = (Graphics2D) image.getGraphics();//画笔
        G.setColor(Color.white);
        G.fillRect(0,0,100,20);
        //绘制图片
        G.setColor(Color.blue);
        G.setFont(new Font(null,Font.BOLD,20));
        G.drawString(makenums(),0,20);
        //设置浏览器打开样式
        resp.setContentType("image/jpeg");
        //清除缓存
        resp.setDateHeader("expires",-1);
        resp.setHeader("Cache-Control","no-cache");
        resp.setHeader("Pragma","no-cache");
        //写到浏览器
        ImageIO.write(image,"jpg", resp.getOutputStream());
    }
    private String makenums(){
        Random random = new Random();
        String nums = random.nextInt(99999999) + "";
        StringBuffer sb=new StringBuffer();
        for (int i = 0; i < 8-nums.length(); i++) {
            sb.append("0");
        }
        nums = sb.toString()+nums;
        return nums;
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

标签：nums,resp,awt,javax,image,import,servlet,response
来源： https://blog.csdn.net/liuwushuang233/article/details/123596385