生成验证码-蒲公英云

生成验证码

朱雀 2022-05-09 09:10 399阅读 0赞

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
@WebServlet("/validcode")
public class ValidCodeServlet extends HttpServlet{
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //创建一张图片
        //单位像素
        BufferedImage image= new BufferedImage(200, 100, BufferedImage.TYPE_INT_RGB);
        //创建画板，如果透明的玻璃
        //想画板上画内容之前得设置画笔
        Graphics2D gra = image.createGraphics();
        gra.setColor(new Color(255, 255, 255));
        gra.fillRect(0, 0, 200, 100);
        List<Integer> randList = new ArrayList<Integer>();
        Random random = new Random();
        for(int i=0;i<4;i++) {
            randList.add(random.nextInt(10));
        }
        Color[] colors = new Color[] {Color.BLUE, Color.CYAN, Color.GRAY,Color.GREEN,Color.ORANGE};
        //字体 宋体，加粗、斜体，字号40
        gra.setFont(new Font("宋体",Font.BOLD|Font.ITALIC,40));
        for (int i=0;i<randList.size();i++) {            
            gra.setColor(colors[random.nextInt(colors.length)]);
            gra.drawString(randList.get(i).toString(), i * 40 , 50 + (random.nextInt(21)-10));
        }
        for (int i=0;i<2;i++) {
            gra.setColor(colors[random.nextInt(colors.length)]);
            gra.drawLine(0,random.nextInt(100), 200, random.nextInt(100));
        }
        ServletOutputStream outputStream = resp.getOutputStream();
        //工具类        
        ImageIO.write(image, "jpg", outputStream);
        //把验证码放入到session中
        HttpSession session = req.getSession();
        session.setAttribute("code", ""+randList.get(0)+randList.get(1)+randList.get(2)+randList.get(3));
    }
}

jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript">
$(function(){
    $("a").click(function(){
        $("img").attr("src","validcode?date="+new Date());
        return false;
    })
})
</script>
</head>
<body>
<form action="login" method="post">
    用户名: <input type="text" name="username"/><br/>
    密    码: <input type="password" name="password"/><br/>
    验证码:<input type="text" size="1" name="code"/><img src="validcode" width="80" height="40"/><a href="">看不清</a><br/>
    <input type="submit" value="登录"/><input type="reset" value="重置">
</form>
</body>
</html>