验证码的显示和切换

servlet

点击查看代码 
package servlet;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
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;

@WebServlet("/CheckCodeServlet")
public class CheckCodeServlet extends HttpServlet {

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       int  width=100;
       int height=50;
        //创建图像进内存
        BufferedImage pic = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

        //美化图片
        Graphics g =pic.createGraphics(); //画笔对象
        g.setColor(Color.PINK);
        g.fillRect(0,0,width,height);
        g.setColor(Color.BLUE);
        g.drawRect(0,0,width-1,height-1);

        String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1230456789";

        for(int i =1;i<=4;i++) {
            Random ran = new Random();
            int r = ran.nextInt(str.length());
            char c = str.charAt(r);
            g.drawString(c+"",width/5*i,height/2);
        }
        g.setColor(Color.GREEN);
        for(int i=1;i<=10;i++){
            Random ran = new Random();
            int x1 = ran.nextInt(width);
            int x2 = ran.nextInt(width);
            int y1 = ran.nextInt(height);
            int y2 = ran.nextInt(height);
            g.drawLine(x1,y1,x2,y2);
        }

        //在浏览器显示
        ImageIO.write(pic,"jpg",resp.getOutputStream());
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }
}
html
点击查看代码 
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <img id="checkCode" src="/Spring_MVC/CheckCodeServlet"/>
    <a id="change" href="">看不清？换一张</a>

</body>

<script>
    window.onload= function (){
    var img  = document.getElementById("checkCode");
    img.onclick= function (){
        //加时间戳
        var date = new Date().getTime();
        img.src="/Spring_MVC/CheckCodeServlet?"+date;
}
}
</script>
</html>
posted @ 2025-05-25 23:09  lfqyj  阅读(67)  评论(0)    收藏  举报