Java实现验证码

这里实现我使用到了struts2模拟一个登录功能来验证java实现的验证码功能。

Java实现验证码的步骤：

1、创建RandomImageGenerator.java类，该类实现验证码图片的生成

2、创建一个servlet类，RandomImageServlet.java，将生成的验证码输出到页面

3、创建一个Action类，LoginAction.java，控制登录

4、配置struts.xml一个web.xml文件

5、编写页面

具体实现用代码表达

1、创建RandomImageGenerator.java类

package com.tenghu.code;import java.awt.Color;import java.awt.Font;import java.awt.Graphics2D;import java.awt.image.BufferedImage;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.OutputStream;import java.util.Random;import javax.imageio.ImageIO;/** * 验证码生成类 * @author xiaohu * */public class RandomImageGenerator {//创建Random对象static Random random=new Random();//随机生成包含验证码字符串public static String random(int num){//初始化种子String[] str={"0","1","2","3","4","5","6","7","8","9",  "a","b","c","d","e","f","g","h","i","j",  "k","l","m","n","p","q","r","s","t"};int number=str.length;//接收随机字符String text = "";//随机产生4个字符的字符串for(int i=0;i<num;i++){text+=str[random.nextInt(number)];}return text;}/** * 随机产生定义的颜色 *  * @return */private static Color getRandColor() {Random random = new Random();Color color[] = new Color[10];color[0] = new Color(32, 158, 25);color[1] = new Color(218, 42, 19);color[2] = new Color(31, 75, 208);color[3] = new Color(0, 102, 182);color[4] = new Color(171, 0, 85);return color[random.nextInt(5)];}/** * 产生随机字体 *  * @return */private static Font getFont() {Random random = new Random();Font font[] = new Font[5];font[0] = new Font("Ravie", Font.BOLD, 30);font[1] = new Font("Antique Olive Compact", Font.BOLD, 30);font[2] = new Font("Forte", Font.BOLD, 30);font[3] = new Font("Wide Latin", Font.BOLD, 30);font[4] = new Font("Gill Sans Ultra Bold", Font.BOLD, 30);return font[random.nextInt(5)];}/** * 生成图片 * @throws IOException  */public static void render(String randomStr,OutputStream out,int width,int height) throws IOException{//在内存中创建图像BufferedImage bi=new BufferedImage(width, height, BufferedImage.TYPE_BYTE_INDEXED);//获取图形上下文Graphics2D g=(Graphics2D) bi.getGraphics();//话边框g.setColor(Color.white);g.fillRect(0, 0, width, height);g.setFont(getFont());g.setColor(Color.BLACK);//画认证码，每个认证码在不同的水平位置String str1[]=new String[randomStr.length()];for(int i=0;i<str1.length;i++){str1[i]=randomStr.substring(i,i+1);int w=0;int x=(i+1)%3;//随机生成验证码字符水平偏移量if(x==random.nextInt(7)){w=30-random.nextInt(7);}else{w=30+random.nextInt(7);}//随机生成颜色g.setColor(getRandColor());g.drawString(str1[i], 20*i+10, w);}//随机产生干扰点，并用不同的颜色表示，事图像的认证码不易被其他程序探测到for(int i=0;i<100;i++){int x=random.nextInt(width);int y=random.nextInt(height);Color color=new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255));//随机画各种颜色的线g.setColor(color);g.drawOval(x, y, 0, 0);}//画干扰线for(int i=0;i<15;i++){int x=random.nextInt(width);int y=random.nextInt(height);int x1=random.nextInt(width);int y1=random.nextInt(height);Color color=new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255));//随机画各种颜色线g.setColor(color);g.drawLine(x, y, x1, y1);}//图像生效g.dispose();//输出页面ImageIO.write(bi, "jpg", out);}public static void main(String[] args) throws FileNotFoundException, IOException {//获取随机字符串String randomStr=random(5);System.out.println(randomStr);//生成图片render(randomStr, new FileOutputStream("D:\\test.jpg"),130,40);}}

2、创建RandomImageServlet.java

package com.tenghu.code.servlet;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import com.tenghu.code.RandomImageGenerator;public class RandomImageServlet extends HttpServlet {//图片宽度int width=0;//图片高度int height=0;//图片上随机字符个数int randomStrNum=0;public void destroy() {}public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {request.setCharacterEncoding("UTF-8");//获取HttpSession对象HttpSession session=request.getSession();//获取随机字符串String randomStr=RandomImageGenerator.random(randomStrNum);if(null!=session){//设置参数session.setAttribute("randomStr", randomStr);//设置响应类型,输出图片客户端不缓存   response.setDateHeader("Expires", 1L);     response.setHeader("Cache-Control", "no-cache, no-store, max-age=0");   response.addHeader("Pragma", "no-cache");   response.setContentType("image/jpeg");

//输出到页面RandomImageGenerator.render(randomStr, response.getOutputStream(), width, height);}}public void init() throws ServletException {//获取宽度width=Integer.parseInt(this.getInitParameter("width"));//获取高度height=Integer.parseInt(this.getInitParameter("height"));//获取个数randomStrNum=Integer.parseInt(this.getInitParameter("num"));}}

3、创建LoginAction.java类

package com.tenghu.code.action;import java.io.ByteArrayInputStream;import java.io.InputStream;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;public class LoginAction extends ActionSupport{//用户名private String userName;//密码private String password;//验证码private String code;private InputStream inputStream;public InputStream getResult(){return inputStream;}//成功public String success() throws Exception{return SUCCESS;}//测试登录public String testLogin() throws Exception{//获取图片的验证码String randomStr=(String) ActionContext.getContext().getSession().get("randomStr");if(code.trim().equalsIgnoreCase(randomStr)){if("admin".equals(userName.trim())&&"admin".equals(password.trim())){//成功inputStream=new ByteArrayInputStream("1".getBytes("UTF-8"));}else{//用户名或密码错误inputStream=new ByteArrayInputStream("2".getBytes("UTF-8"));}}else{//验证码错误inputStream=new ByteArrayInputStream("0".getBytes("UTF-8"));}return "result";}public String getUserName() {return userName;}public void setUserName(String userName) {this.userName = userName;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getCode() {return code;}public void setCode(String code) {this.code = code;}}

4、配置struts.xml、web.xml文件

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE struts PUBLIC"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN""http://struts.apache.org/dtds/struts-2.3.dtd"><struts><package name="installs" extends="struts-default"><action name="login" class="com.tenghu.code.action.LoginAction"><!-- 登录成功到success.jsp页面 --><result name="success">success.jsp</result><!-- 登录验证返回的数据 --><result name="result" type="stream"><param name="contentType">text/html</param><param name="inputName">result</param></result></action></package></struts>

 

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" 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_2_5.xsd">  <servlet>    <description>This is the description of my J2EE component</description>    <display-name>This is the display name of my J2EE component</display-name>    <servlet-name>RandomImageServlet</servlet-name>    <servlet-class>com.tenghu.code.servlet.RandomImageServlet</servlet-class>    <!-- 初始化图片宽度 -->    <init-param>    <param-name>width</param-name>    <param-value>130</param-value>    </init-param>    <!-- 初始化图片高度 -->    <init-param>    <param-name>height</param-name>    <param-value>40</param-value>    </init-param>    <!-- 初始化图片随机数个数 -->    <init-param>    <param-name>num</param-name>    <param-value>4</param-value>    </init-param>  </servlet>  <servlet-mapping>    <servlet-name>RandomImageServlet</servlet-name>    <url-pattern>/verification.do</url-pattern>  </servlet-mapping>  <!-- 配置struts核心过滤器 -->  <filter>  <filter-name>struts2</filter-name>  <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>  </filter>  <filter-mapping>  <filter-name>struts2</filter-name>  <url-pattern>/*</url-pattern>  </filter-mapping>  <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list></web-app>

5、编写测试页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'index.jsp' starting page</title><script type="text/javascript" src="js/jquery-1.10.2.min.js"></script><script type="text/javascript" src="js/jquery.form.js"></script><script type="text/javascript">$(document).ready(function(){CODE.initCode();//验证输入function checkInput(){if($('#userName').val()==''){alert('用户名不能为空！');return false;}if($('#password').val()==''){alert('密码不能为空！');return false;}if($('#code').val()==''){alert('验证码不能为空！');return false;}return true;}//点击按钮$('#btn').click(function(){if(checkInput()==true){$('#login_request').ajaxSubmit({url:'login!testLogin',cache:false,type:'POST',success:function(data){if(data==0){alert('验证码错误！');//改变验证码CODE.initCode();}else if(data==1){alert('登录成功！');//提交到登录成功页面$('#login_request')[0].submit();}else if(data==2){alert('用户名或密码错误！');//改变验证码CODE.initCode();}},error:function(e){alert('出错了！');}}); }});});var CODE={//初始化化验证码initCode:function(){$("#code_img").attr("src","verification.do?rmd="+new Date().getTime())//如果需要点击图片改变图片的内容，则必须添加时间搓.click(function(){$(this).attr("src","verification.do?rmd="+new Date().getTime());});}};</script>  </head>    <body>  <form action="login!success" id="login_request" method="post">  UserName:<input type="text" id="userName" name="userName"/><br/>  Password:<input type="password" id="password" name="password"/><br>  Verification_Code:<input type="text" id="code" name="code"/><img id="code_img" style="position:relative;top:8px;height:25px"><br>  <input type="button" id="btn" value="登录"/>  </form>  </body></html>

成功页面就部贴出来了，就是一段文字而已
显示结果：