您的位置：首页 > 编程语言 > Java开发

IDEA JavaWeb验证码的实现和切换

2020-04-19 23:20 447 查看

验证码
1. 本质：图片
2. 目的：防止恶意表单注册

1.创建CheckCodeServlet

package cn.mimihany.web.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 {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
int width =100;
int height = 50;
//1.创建一对象，在内存中图片（验证码图片对象）
BufferedImage image =new BufferedImage(width,height,BufferedImage.TYPE_INT_BGR);
//2.美化图片
//2.1填充背景色
Graphics g = image.getGraphics();//画笔对象
g.setColor(Color.pink);//设置画笔颜色
g.fillRect(0,0,width,height);
//2.2画边框
g.setColor(Color.BLUE);
g.drawRect(0,0,width-1,height-1);

String str="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
//生成随机角标
Random ran= new Random();
for (int i = 1; i <=4; i++) {
int index = ran.nextInt(str.length());
//获取字符
char ch = str.charAt(index);//随机字符
//2.3写验证码
g.drawString(ch+"",width/5*i,height/2);
}

//2.4画干扰线
g.setColor(Color.green);
//随机生成坐标点
for (int i = 0; i <10 ; i++) {
int x1 = ran.nextInt(width);
int x2= ran.nextInt(width);
int y1 = ran.nextInt(height);
int y2 = ran.nextInt(height);
g.drawLine(x1,x2,y1,y2);
}

//3.将图片输出到页面展示
ImageIO.write(image,"jpg",response.getOutputStream());
}

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}

2.创建register.html

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script>
/*
分析：点击超链接或者图片，需要换一张
1.给超链接和图片绑定单击事件
2.重新设置图片的src属性值
*/

window.onload = function (ev) {
//1.获取图片对象
var img = document.getElementById("checkCode");

//2.绑定单击事件
img.onclick= function (ev1) {
//获取时间戳
var date =new Date().getTime();
img.src ="/resp/checkCodeServlet?"+date;
}

var c = document.getElementById("change");
c.onclick = function (ev1) {
//获取时间戳
var date =new Date().getTime();
img.src ="/resp/checkCodeServlet?"+date;
}
}
</script>
</head>
<body>
<img id="checkCode" src="/resp/checkCodeServlet">
<a id="change" href="">看不清换一张</a>
</body>
</html>
  • 点赞
  • 收藏
  • 分享
  • 文章举报
mimihanyzz 发布了5 篇原创文章 · 获赞 0 · 访问量 326 私信 关注
内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理 点击这里给我发消息
标签： 
相关文章推荐
新的分享
章节导航