servlet生成验证码和点击刷新验证码-蒲公英云

servlet生成验证码和点击刷新验证码

- 日理万妓 2022-03-21 06:46 555阅读 0赞

javaweb项目，有两个文件，一个java文件，用来生成验证码并输出到servlet输出流中。一个html文件，用来写组件和点击事件，刷新验证码。

CodeServlet.java文件

package net.test.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(name = "CodeServlet",urlPatterns = "/code")
public class CodeServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    }
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        int width=100;
        int height=30;
        String str="qwertyuiopasdfghjklzxcbnm123456789";
        Random random = new Random();
        BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
        Graphics graphics = image.getGraphics();
        graphics.drawRect(0,0,100,30);
        for (int i = 0; i < 4; i++) {
            int number=random.nextInt(str.length());
            String a=str.substring(number,number+1);
            graphics.drawString(a,20*(i+1),15);
        }
        ImageIO.write(image,"jpg",resp.getOutputStream());
    }
}

login.html文件

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>验证码</title>
</head>
<body>
    <image id="verifycode" src="code" onclick="this.src=this.src+'?'+Math.random()" "btn.isDisable=false"></image>
    <button id="btn" onclick="document.getElementById('verifycode').click()">刷新验证码</button>
</body>
</html>