验证码生成与验证-优快云博客

一)处理类

package com.shine.model;

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 = 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
        /*
         * 获得字体
         */
        private Font getFont(){
            return new Font("Fixedsys",Font.CENTER_BASELINE,18);
        }
        /*
         * 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,18));
            g.setColor(getRandColor(110, 133));

            g.drawRect(0, 0, width - 1, height - 1);
            //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, 16);
            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(13);
            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));
        }
}

二)调用

package com.shine.web;

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.shine.model.RandomValidateCode;

@SuppressWarnings("serial")
public class ImageServlet extends HttpServlet
{

   @Override
   protected void doGet(HttpServletRequest request, HttpServletResponse response)
           throws ServletException, IOException {
       doPost(request, response);
   }

   @Override
   protected void doPost(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();
            }
        }

}

package com.shine.web;

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;

public class CheckServlet extends HttpServlet{

   @Override
   protected void doGet(HttpServletRequest request, HttpServletResponse response)
           throws ServletException, IOException {
       // TODO Auto-generated method stub
       doPost(request, response);
   }

   @Override
   protected void doPost(HttpServletRequest request, HttpServletResponse response)
           throws ServletException, IOException {

       HttpSession session=request.getSession();
       String ss=(String) session.getAttribute("RANDOMVALIDATECODEKEY");

       request.setAttribute("check",ss);

       request.getRequestDispatcher("/index.jsp").forward(request, response);

   }

}

<?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>
    <servlet-name>ImageServlet</servlet-name>
    <servlet-class>com.shine.web.ImageServlet</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>ImageServlet</servlet-name>
    <url-pattern>/imageServlet</url-pattern>
</servlet-mapping>

      <servlet>
    <servlet-name>checkServlet</servlet-name>
    <servlet-class>com.shine.web.CheckServlet</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>checkServlet</servlet-name>
    <url-pattern>/checkServlet</url-pattern>
</servlet-mapping>
</web-app>

三)页面

<%@ 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 'img.jsp' starting page</title>

      <script type="text/javascript">
    function refresh(obj) {
        obj.src = "imageServlet?"+Math.random();
    }
    </script>

</head>

<body>
      <form action="checkServlet" method="post">
        <label>输入验证码</label><br/>
        <input type="text" name="randomCode"/><img title="点击更换" onclick="javascript:refresh(this);" src="imageServlet"><br/>
        <input type="submit" value="submit">
    </form>
</body>
</html>