01: /*
02: * This program is free software; you can redistribute it and/or modify
03: * it under the terms of the GNU General Public License as published by
04: * the Free Software Foundation; either version 2 of the License, or
05: * (at your option) any later version.
06: *
07: * This program is distributed in the hope that it will be useful,
08: * but WITHOUT ANY WARRANTY; without even the implied warranty of
09: * 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;
19:
20: import javax.servlet.ServletException;
21: import javax.servlet.http.HttpServlet;
22: import javax.servlet.http.HttpServletRequest;
23: import javax.servlet.http.HttpServletResponse;
24: import javax.servlet.http.HttpSession;
25:
26: import dlog4j.util.image.RandomImageGenerator;
27:
28: /**
29: * 用于产生注册用户时的随即图片以防止非法攻击
30: * @author Liudong
31: */
32: public class RandomImageServlet extends HttpServlet {
33:
34: public final static String RANDOM_LOGIN_KEY = "RANDOM_LOGIN_KEY";
35:
36: public void init() throws ServletException {
37: System.setProperty("java.awt.headless", "true");
38: }
39:
40: public static String getRandomLoginKey(HttpServletRequest req) {
41: return (String) req.getSession().getAttribute(RANDOM_LOGIN_KEY);
42: }
43:
44: protected void doGet(HttpServletRequest req, HttpServletResponse res)
45: throws ServletException, IOException {
46: HttpSession ssn = req.getSession();
47: if (ssn != null) {
48: String randomString = RandomImageGenerator.random();
49: ssn.setAttribute(RANDOM_LOGIN_KEY, randomString);
50: res.setContentType("image/jpeg");
51: RandomImageGenerator.render(randomString, res
52: .getOutputStream());
53: }
54: }
55: }
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