java验证码的生成

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突然回首，从事java开发的工作已有1年多的时间了。由于所在公司的工作环境比较特殊，而且公司做的产品比较老，很少用到新的技术，所以感觉自己已经渐行渐远了。

我觉得有必要去巩固下旧的知识并且学习新的技术。

从零开始吧、、、、、、

今天说下验证码的生成：

通常一些需要注册的地方都会有验证码，这是一种趋势了，随着技术的进步，验证码现在也越来越多样化，我这里还是介绍比较传统一点的方法。

一、你需要一个生成验证码的类：

package lichao.verificationcode;import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.io.IOException;import java.io.OutputStream;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;/** * 生成验证码 * @author Administrator * */public class GetVerificationCode extends HttpServlet{private static final long serialVersionUID = 1L;private static final int WIDTH = 73;//图片的宽度private static final int HEIGHT = 20;//图片的高度//验证码集合共62个字符private static final char[] CODES = {'0','1','2','3','4','5','6','7','8','9','q','w','e','r','t','y','u','i','o','p','a','s','d','f','g','h','j','k','l','z','x','c','v','b','n','m','Q','W','E','R','T','Y','U','I','O','P','A','S','D','F','G','H','J','K','L','Z','X','C','V','B','N','M'};@Overrideprotected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {BufferedImage image = new BufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB);//创建一个图像，TYPE_INT_RGB表示一个图像，能合成整数像素的八位RGB颜色分量Graphics g = image.getGraphics();//获取一个画笔，用来画想要的图像g.setColor(getRandColor(200,250));//设置图像的背景色g.fillRect(0, 0, WIDTH, HEIGHT);Random random = new Random();//创建一个随机对象String srand = "";//用于存储最终的验证码for(int i=0;i<4;i++){String rand = String.valueOf(CODES[random.nextInt(62)]);srand += rand;}g.setColor(getRandColor(100,120));g.setFont(new Font(null,Font.ITALIC, 20));g.drawString(srand, 6, 18);/** * 干扰线条 * */for(int i=0;i<6;i++){g.setColor(getRandColor(150,200));g.drawLine(random.nextInt(WIDTH), random.nextInt(HEIGHT),random.nextInt(WIDTH), random.nextInt(HEIGHT));}resp.setContentType("image/jpeg");OutputStream out = resp.getOutputStream();//获取输出流ImageIO.write(image, "jpeg",out);//把图片输出out.close();}/** * 生成随机的颜色 * */private Color getRandColor(int fc,int bc){Random random = new Random();int r = fc + random.nextInt(bc-fc);int g = fc + random.nextInt(bc-fc);int b = fc + random.nextInt(bc-fc);return new Color(r,g,b);}}

二、你需要一个页面去展示你的验证码：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'index.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><style type="text/css">.login_a{list-style-type: none;}</style>  </head>  <%   String incode = (String)request.getParameter("code");    String rightcode = (String)session.getAttribute("rCode");   %>  <body>    登陆 <br>    <div id="wrap">    <form action="index.jsp" name="queryForm" id="queryForm" method="post">    <div id="login">    <ul class="login_a">    <li>用户名：<input type="text" name="username" id="username"/></li>    <li>密码：<input type="text" name="password" id="password"/></li>    <li class="code">验证码：<input type="text" name="checkCode" id="checkCode"/><img id="codes" src="getVerificationCode.do"/><a href="" onclick="javascript:document.getElementById('verificationCode').src='verificationCode.do?Math.random()'">换一张</a></li>    <li><input type="submit" value="提交" /></li>    </ul>    </div>    </form>    </div>  </body></html>

三、配置下验证码的访问url：web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">  <display-name></display-name>  <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list>  <servlet>  <servlet-name>getCode</servlet-name>  <servlet-class>lichao.verificationcode.GetVerificationCode</servlet-class>  </servlet>  <servlet-mapping>  <servlet-name>getCode</servlet-name>  <url-pattern>/getVerificationCode.do</url-pattern>  </servlet-mapping></web-app>

在浏览器输入访问地址：http://localhost:8080/test001/

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