java开发篇---验证码

package com.oumyye.util;
/*
 * 作者：oumyye
 */
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 RandomValidateCode {

    public static final String RANDOMCODEKEY = "RANDOMVALIDATECODEKEY";//放到session中的key
    private Random random = new Random();
    private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生的字符串
    
    private int width = 120;//图片宽
    private int height = 40;//图片高
    private int lineSize = 40;//干扰线数量
    private int stringNum = 6;//随机产生字符数量
    /*
     * 获得字体
     */
    private Font getFont(){
        return new Font("Fixedsys",Font.CENTER_BASELINE,20);
    }
    /*
     * 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);
    }
    /**
     * 生成随机图片
     */
    public void 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,20));
        g.setColor(getRandColor(100, 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();
        }
    }
    /*
     * 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, 30);
        return randomString;
    }
    /*
     * 绘制干扰线
     */
    private void drowLine(Graphics g){
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(10);
        int yl = random.nextInt(15);
        g.drawLine(x, y, x+xl, y+yl);
    }
    /*
     * 获取随机的字符
     */
    public String getRandomString(int num){
        return String.valueOf(randString.charAt(num));
    }
}

package com.oumyye.servlet;
/**
 * 作者：oumyye
 */
import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.oumyye.util.RandomValidateCode;

public class ImageServlet extends HttpServlet {

    /**
     * Constructor of the object.
     */
    public ImageServlet() {
        super();
    }

    /**
     * Destruction of the servlet. <br>
     */
    public void destroy() {
        super.destroy(); // Just puts "destroy" string in log
        // Put your code here
    }

    /**
     * The doGet method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to get.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    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);
            RandomValidateCode randomValidateCode = new RandomValidateCode();
            try {
                randomValidateCode.getRandcode(request, response);//输出图片方法
            } catch (Exception e) {
                e.printStackTrace();
            }
    }

    /**
     * The doPost method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to post.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

         doGet(request, response);
    }

    /**
     * Initialization of the servlet. <br>
     *
     * @throws ServletException if an error occurs
     */
    public void init() throws ServletException {
        // Put your code here
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">
  <display-name>0001web</display-name>
   <servlet>
    <description>ImageCreate</description>
    <display-name>ImageCreate</display-name>
    <servlet-name>ImageServlet</servlet-name>
    <servlet-class>com.oumyye.servlet.ImageServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>ImageServlet</servlet-name>
    <url-pattern>/servlet/ImageServlet</url-pattern>
  </servlet-mapping>
</web-app>

<!DOCTYPE html>
<html>
  <head>
    <title>验证码</title>
    <!-- Bootstrap -->
    <meta charset="utf-8"> 
    <link href="bootstrap/css/bootstrap.min.css" rel="stylesheet" media="screen">
    <link href="bootstrap/css/bootstrap-responsive.min.css" rel="stylesheet" media="screen">
    <link href="assets/styles.css" rel="stylesheet" media="screen">
     <!-- HTML5 shim, for IE6-8 support of HTML5 elements -->
    <!--[if lt IE 9]>
      <script src="http://html5shim.googlecode.com/svn/trunk/html5.js"></script>
    <![endif]-->
    <script src="vendor/modernizr-2.6.2-respond-1.1.0.min.js"></script>
    
    <script type="text/javascript">
    function refresh(obj) {
        obj.src = "servlet/ImageServlet?"+Math.random();
    }
    </script>
    
    
  </head>
  <body id="login">
   
        <input type="text" placeholder="验证码" name="imageCode" id="randomCode" onblur="checkImage()" style="width:58%;" required>
        <img title="点击更换" onclick="javascript:refresh(this);" src="servlet/ImageServlet" style="margin-top:-16px;"><br/>
        <div id="checkBody">
        </div>
    <!-- /container -->
    <script src="vendors/jquery-1.9.1.min.js"></script>
    <script src="bootstrap/js/bootstrap.min.js"></script>
    <script type="text/javascript">
    
    var xmlHttp ;
    function createXMLHttpRequest(){
        if(window.ActiveXOBject){
            xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
        }else if(window.XMLHttpRequest){
            xmlHttp = new XMLHttpRequest();
        }
    }
    
    
    function checkImage(){
        var  imageCode = document.getElementById("randomCode").value;
        if(imageCode==""||imageCode==null){
            document.getElementById("checkBody").innerHTML="" +
            "<div class=‘alert alert-danger‘ role=‘alert‘>请输入验证码!</div> " ;
            document.getElementById("randomCode").focus() ;
            return false ;
        }
        
        var url = "userCheckCodeAction.action?imageCode="+imageCode;
        createXMLHttpRequest();
        xmlHttp.onreadystatechange = processorCheckImage;
        xmlHttp.open("POST",url,true);
        xmlHttp.send();
    }
    
    function processorCheckImage(){
        var responseContext ;
        if(xmlHttp.readyState==4){
            if(xmlHttp.status==200){
                responseContext = xmlHttp.responseText;
                
                if(responseContext.indexOf("failure")!=-1){
                    
                    document.getElementById("checkBody").innerHTML="" +
                    "<div class=‘alert alert-danger‘ role=‘alert‘>验证码错误!</div> " ;
                    document.getElementById("randomCode").focus() ;
                    return false ;
                }else{
                    document.getElementById("checkBody").innerHTML="" +
                            "<div class=‘alert alert-success‘ role=‘alert‘>验证码正确 !</div> " ;
                            
                    document.getElementById("submitBtn").innerHTML="" +        
                            "<button class=‘btn btn-large btn-primary‘ type=‘submit‘ style=‘width:80%;‘ >登  陆</button>" ;
                    return true ;
        }
    }
}
}

    </script>
    
    
  </body>
</html>