jsp实现字母和数字验证码功能

来源：互联网发布：网络代理兼职加盟编辑：程序博客网时间：2024/06/05 20:25

1.新建一个Dynamic Web Project项目，里面新建两个servlet文件和一个jsp文件，整体的项目框架如图所示：

2.ImageServlet.java里面的代码如下所示：

package servlet;import java.awt.Color;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.io.IOException;import java.util.Random;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;@WebServlet(name = "imageServlet", urlPatterns = { "/imageServlet" })public class ImageServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {doPost(request, response);}protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {BufferedImage bi = new BufferedImage(68, 22, BufferedImage.TYPE_INT_RGB);Graphics g = bi.getGraphics();Color c = new Color(200, 150, 255);g.setColor(c);g.fillRect(0, 0, 68, 22);String ch = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";Random r = new Random();int len = ch.length();int index;StringBuffer sb = new StringBuffer();for (int i = 0; i < 4; i++) {index = r.nextInt(len);g.setColor(new Color(r.nextInt(88), r.nextInt(188), r.nextInt(255)));g.drawString(ch.substring(index, index + 1) + "", (i * 15) + 3, 18);sb.append(ch.substring(index, index + 1) + "");}request.getSession().setAttribute("piccode", sb.toString());ImageIO.write(bi, "JPG", response.getOutputStream());}}

3.LoginServlet.java里面的代码如下所示：

package servlet;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;@WebServlet(name = "loginServlet", urlPatterns = { "/loginServlet" })public class LoginServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {doPost(request, response);}protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {String piccode = (String) request.getSession().getAttribute("piccode");String checkcode = request.getParameter("checkcode");response.setContentType("text/html;charset=utf-8");PrintWriter out = response.getWriter();if (checkcode.equals(piccode)) {out.println("验证码输入正确！");} else {out.println("验证码输入错误！");}out.flush();out.close();}}

4.index.jsp里面的代码如下所示:

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>验证码</title><script type="text/javascript">function reloadCode() {var time = new Date().getTime();document.getElementById("imagecode").src = "imageServlet?d=" + time;}</script></head><body><form action="loginServlet" method="post">验证码： <input type="text" name="checkcode"/> <img alt="验证码" id="imagecode" src="imageServlet"/> <a href="javascript:reloadCode();">看不清楚</a> <br><input type="submit" value="提交"/></form></body></html>

5.在浏览器里面输入http://localhost:8080/CheckCode/loginServlet可以得到验证码的实现。

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