Servlet验证码功能

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Servlet验证码功能

创建验证码生成Servlet

package com.pc.verifycode;import java.awt.Color;import java.awt.Font;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.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class VerifyServlet extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        // 使用java图形界面技术绘制一张图片        int charNum = 4;        int width = 20 * 4;        int height = 28;        // 1. 创建一张内存图片        BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);        // 2.获得绘图对象        Graphics graphics = bufferedImage.getGraphics();        // 3、绘制背景颜色        graphics.setColor(Color.YELLOW);        graphics.fillRect(0, 0, width, height);        // 4、绘制图片边框        graphics.setColor(Color.GRAY);        graphics.drawRect(0, 0, width - 1, height - 1);        // 5、输出验证码内容        graphics.setColor(Color.RED);        graphics.setFont(new Font("宋体", Font.BOLD, 22));        // 随机输出4个字符        String s = "ABCDEFGHGKLMNPQRSTUVWXYZ23456789";        Random random = new Random();        // session中要用到        String msg = "";        int x = 5;        for (int i = 0; i < charNum; i++) {            int index = random.nextInt(32);            String content = String.valueOf(s.charAt(index));            msg += content;            graphics.setColor(new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255)));            graphics.drawString(content, x, 22);            x += 20;        }        // 6、绘制干扰线        graphics.setColor(Color.GRAY);        for (int i = 0; i < 5; i++) {            int x1 = random.nextInt(width);            int x2 = random.nextInt(width);            int y1 = random.nextInt(height);            int y2 = random.nextInt(height);            graphics.drawLine(x1, y1, x2, y2);        }        // 释放资源        graphics.dispose();        // 图片输出 ImageIO        ImageIO.write(bufferedImage, "jpg", response.getOutputStream());    }    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        doGet(request, response);    }}

修改web.xml

<servlet>    <servlet-name>VerifyServlet</servlet-name>    <servlet-class>com.pc.verifycode.VerifyServlet</servlet-class></servlet><servlet-mapping>    <servlet-name>VerifyServlet</servlet-name>    <url-pattern>/VerifyServlet</url-pattern></servlet-mapping>

创建登录jsp

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%><!DOCTYPE html><html>    <head>        <meta charset=utf-8">        <title>Login</title>    </head>    <body>        <%-- 演示验证码功能 --%>        <form action="#" method="post">                用户名：<input type="text" name="username" /><br /><br />                密码：<input type="password" name="password" /><br /><br />                验证码：<input type="text" name="verifyCode" />                <img src="${pageContext.servletContext.contextPath }/VerifyServlet" id="verifyImg"><br />                <input type="submit" value="登录" />        </form>    </body></html>

head标签后加入js实现点击刷新验证码

    <!-- 引入jquery库 -->    <script type="text/javascript" src="${pageContext.servletContext.contextPath }/resource/js/jquery-1.11.0.js"></script>    <!-- 写一个验证码点击刷新功能 -->    <script type="text/javascript">        $(function() {            $("#verifyImg").click(function() {                $(this).prop("src", "${pageContext.servletContext.contextPath }/VerifyServlet?t=" + new Date().getTime());            });        });    </script>

PS：GitHub：https://github.com/Switch-vov/servlet-tools

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