java实现网页验证码
Posted 必须往前走
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了java实现网页验证码相关的知识，希望对你有一定的参考价值。
Servlet:
package cn.bdqn.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.font.ImageGraphicAttribute;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
@WebServlet(name = "Servlet",urlPatterns = "/yanCode")
public class Servlet extends HttpServlet {
public void doPost(javax.servlet.http.HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request,response);
}
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String s="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
Random random = new Random();
int width=500;
int height=50;
BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
Graphics graphics = image.getGraphics();//相当于画笔
//画背景
graphics.setColor(Color.gray);
graphics.fillRect(0,0,width,height);
graphics.setColor(Color.black);
for (int i = 0; i <4 ; i++) {
int index = random.nextInt(s.length());
String c = s.substring(index, index + 1);
graphics.drawString(c,width/5*(i+1),15);
}
ImageIO.write(image,"jpg",response.getOutputStream());
}
}
jsp:
<%-- Created by IntelliJ IDEA. User: Administrator Date: 2017/10/10 Time: 13:04 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>验证码</title> </head> <body> <img src="yanCode" alt="验证码" style="width: 500px;height:50px"> <input type="button" value="看不清,更换验证码" id="btn" onclick="changeCode();"> <script type="text/javascript" src="js/jquery.min.js"> </script> <script type="text/javascript" > function changeCode() { $("img").attr(‘src‘, ‘yanCode?ts=‘ + new Date().getTime()); } </script> </body> </html>
以上是关于java实现网页验证码的主要内容，如果未能解决你的问题，请参考以下文章