KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > dlog4j > RandomImageServlet


1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License as published by
4  * the Free Software Foundation; either version 2 of the License, or
5  * (at your option) any later version.
6  *
7  * This program is distributed in the hope that it will be useful,
8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10  * GNU Library General Public License for more details.
11  *
12  * You should have received a copy of the GNU General Public License
13  * along with this program; if not, write to the Free Software
14  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
15  */

16 package dlog4j;
17
18 import java.io.IOException JavaDoc;
19
20 import javax.servlet.ServletException JavaDoc;
21 import javax.servlet.http.HttpServlet JavaDoc;
22 import javax.servlet.http.HttpServletRequest JavaDoc;
23 import javax.servlet.http.HttpServletResponse JavaDoc;
24 import javax.servlet.http.HttpSession JavaDoc;
25
26 import dlog4j.util.image.RandomImageGenerator;
27
28
29 /**
30  * 用于产生注册用户时的随即图片以防止非法攻击
31  * @author Liudong
32  */

33 public class RandomImageServlet extends HttpServlet JavaDoc {
34
35     public final static String JavaDoc RANDOM_LOGIN_KEY = "RANDOM_LOGIN_KEY";
36
37     public void init() throws ServletException JavaDoc {
38         System.setProperty("java.awt.headless","true");
39     }
40     
41     public static String JavaDoc getRandomLoginKey(HttpServletRequest JavaDoc req) {
42         return (String JavaDoc)req.getSession().getAttribute(RANDOM_LOGIN_KEY);
43     }
44     
45     protected void doGet(HttpServletRequest JavaDoc req, HttpServletResponse JavaDoc res) throws ServletException JavaDoc, IOException JavaDoc
46     {
47         HttpSession JavaDoc ssn = req.getSession();
48         if(ssn!=null) {
49             String JavaDoc randomString = RandomImageGenerator.random();
50             ssn.setAttribute(RANDOM_LOGIN_KEY,randomString);
51             res.setContentType("image/jpeg");
52             RandomImageGenerator.render(randomString,res.getOutputStream());
53         }
54     }
55 }
56
Popular Tags