验证码生成

来源：互联网发布：詹姆斯打球特点知乎编辑：程序博客网时间：2024/05/01 16:51

首先上个图：

index.jsp页面的代码如下：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>验证码</title><script type="text/javascript">function refresh(obj) {obj.src = "validateCodeServlet?" + Math.random();}</script></head><body><form action="registerServlet" method="post"><label>输入验证码</label><br /><input type="text" name="validateCode" /><img id="imgValidateCode" title="点击更换" onclick="refresh(this);"border="1" src="validateCodeServlet"><br /><input type="submit" value="提交"></form></body></html>

页面请求的Servlet（ValidateCodeServlet.java）代码如下：

package cn.com;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class ValidateCodeServlet extends HttpServlet {private static final long serialVersionUID = -9008764210373468163L;public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("image/jpeg");// 设置相应类型,告诉浏览器输出的内容为图片response.setHeader("Pragma", "No-cache");// 设置响应头信息，告诉浏览器不要缓存此内容response.setHeader("Cache-Control", "no-cache");response.setDateHeader("Expire", 0);ValidateCode randomValidateCode = new ValidateCode();randomValidateCode.getRandcode(request, response);// 输出图片方法}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}}

关键类ValidateCode.java主要用来生成彩色的验证图片。代码如下：

package cn.com;import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;public class ValidateCode {public static final String RANDOMCODEKEY = "RANDOMVALIDATECODEKEY";// 放到session中的keyprivate Random random = new Random();private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";// 随机产生的字符串private int width = 80;// 图片宽private int height = 26;// 图片高private int lineSize = 40;// 干扰线数量private int stringNum = 4;// 随机产生字符数量/** * 生成随机图片 */public String getRandcode(HttpServletRequest request,HttpServletResponse response) {HttpSession session = request.getSession();// BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_BGR);Graphics g = image.getGraphics();// 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作g.fillRect(0, 0, width, height);g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));g.setColor(getRandColor(110, 133));// 绘制干扰线for (int i = 0; i <= lineSize; i++) {drowLine(g);}// 绘制随机字符String randomString = "";for (int i = 1; i <= stringNum; i++) {randomString = drowString(g, randomString, i);}session.removeAttribute(RANDOMCODEKEY);session.setAttribute(RANDOMCODEKEY, randomString);System.out.println(randomString);g.dispose();try {ImageIO.write(image, "JPEG", response.getOutputStream());// 将内存中的图片通过流动形式输出到客户端} catch (Exception e) {e.printStackTrace();return "";}return randomString;}/* * 获得颜色 */private Color getRandColor(int fc, int bc) {if (fc > 255)fc = 255;if (bc > 255)bc = 255;int r = fc + random.nextInt(bc - fc - 16);int g = fc + random.nextInt(bc - fc - 14);int b = fc + random.nextInt(bc - fc - 18);return new Color(r, g, b);}/* * 绘制字符串 */private String drowString(Graphics g, String randomString, int i) {g.setFont(getFont());g.setColor(new Color(random.nextInt(101), random.nextInt(111), random.nextInt(121)));String rand = String.valueOf(getRandomString(random.nextInt(randString.length())));randomString += rand;g.translate(random.nextInt(3), random.nextInt(3));g.drawString(rand, 13 * i, 16);return randomString;}/* * 获得字体 */private Font getFont() {return new Font("Fixedsys", Font.CENTER_BASELINE, 18);}/* * 绘制干扰线 */private void drowLine(Graphics g) {int x = random.nextInt(width);int y = random.nextInt(height);int xl = random.nextInt(13);int yl = random.nextInt(15);g.drawLine(x, y, x + xl, y + yl);}/* * 获取随机的字符 */private String getRandomString(int num) {return String.valueOf(randString.charAt(num));}}

验证类RegisterServlet.java代码如下：

package cn.com;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class RegisterServlet extends HttpServlet {private static final long serialVersionUID = -5800963733541887975L;public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {if (!request.getParameter("validateCode").toUpperCase().equals(request.getSession().getAttribute(ValidateCode.RANDOMCODEKEY).toString()))System.out.println("验证错误");elseSystem.out.println("验证通过");}}

最后是web.xml的配置：

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"><servlet><description>生成验证码</description><servlet-name>ValidateCodeServlet</servlet-name><servlet-class>cn.com.ValidateCodeServlet</servlet-class></servlet><servlet><description>注册</description><servlet-name>RegisterServlet</servlet-name><servlet-class>cn.com.RegisterServlet</servlet-class></servlet><servlet-mapping><servlet-name>ValidateCodeServlet</servlet-name><url-pattern>/validateCodeServlet</url-pattern></servlet-mapping><servlet-mapping><servlet-name>RegisterServlet</servlet-name><url-pattern>/registerServlet</url-pattern></servlet-mapping><welcome-file-list><welcome-file>index.jsp</welcome-file></welcome-file-list></web-app>