Cookie Counter

Cookie Counter

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

public class cc extends HttpServlet {

        private PrintWriter toClient;
        private String FILENAME;
        private int MAX_DIGIT;
        private String COOKIE_NAME;

        public void init(ServletConfig sc) throws ServletException {

                super.init(sc);
                String temp;
                FILENAME = sc.getInitParameter("FILENAME");
                temp = sc.getInitParameter("MAX_DIGIT");
                COOKIE_NAME = sc.getInitParameter("COOKIE_NAME");

                try {
                        MAX_DIGIT = Integer.parseInt(temp);
                }catch(Exception e) {

                        error_handling (e, "ERROR parsing temp to MAX_DIGIT");
                }

                try {
                        File f = new File(FILENAME);
                        if(!f.exists()) {
                                RandomAccessFile raf = new RandomAccessFile(FILENAME,"rw");
                                raf.writeBytes("0");
                                raf.close();
                        }
                }catch (IOException e) {
                        error_handling(e, "Error checking file");
                }
        }

        protected synchronized int[] getHitCountOnly(String filename) {
                String dat=null,index;
                int now,datLength;
                int digit[] = new int[MAX_DIGIT];
                char temp;

                try {
                        RandomAccessFile fromFile = new RandomAccessFile("counter.dat","rw");
                        dat=fromFile.readLine();
                } catch(IOException e) {
                        error_handling (e, "Error get hit count");
                }

                datLength = dat.length();
                for (int i=0; i < MAX_DIGIT - datLength; i++)
                        digit[i]=0;
                for(int i = 0; i < datLength; i++) {
                        temp = dat.charAt(i);
                        index = temp+"";
                        digit[i + MAX_DIGIT - datLength] = Integer.parseInt(index);
                }
                return digit;
        }


        protected synchronized int[] UpdateHitCount(String filename) {

                String dat=null,index;
                int now,datLength;
                int digit[] = new int[MAX_DIGIT];
                char temp;

                try {
                        RandomAccessFile fromFile = new RandomAccessFile("counter.dat","rw");
                        dat=fromFile.readLine();

                        now = Integer.parseInt(dat);
                        now ++;
                        dat = Integer.toString(now);
                        fromFile.seek(0);
                        fromFile.writeBytes(now+"\n");
                        fromFile.close();
                } catch(IOException e) {
                        error_handling (e, "Error updating hit count");
                }

                datLength = dat.length();
                for (int i=0; i < MAX_DIGIT - datLength; i++) digit[i]=0;
                        for(int i = 0; i < datLength; i++) {
                                temp = dat.charAt(i);
                                index = temp+"";
                                digit[i + MAX_DIGIT - datLength] = Integer.parseInt(index);
                        }
                return digit;
        }
        protected Cookie getCookie(HttpServletRequest req, String c_name) {
                Cookie[] cookies = req.getCookies();
                if(cookies!=null) {
                        for(int i=0; i < cookies.length; i++) {
                                if(cookies[i].getName().equals(c_name)) {

                                        return cookies[i];
                                }
                        }
                return null;
        }

        public void setCookie(HttpServletResponse res, String c_name) {
                Date date = new Date();
                String visit = date.toString();
                Cookie logged = new Cookie(c_name, visit);
                res.addCookie(logged);
        }

        public void service (HttpServletRequest req,HttpServletResponse res) throws ServletException, IOException {

                int digit[] = new int[MAX_DIGIT];
                Cookie curr_Cookie = getCookie(req, COOKIE_NAME);
                if(curr_Cookie == null) {
                        setCookie(res,COOKIE_NAME);
                        digit = UpdateHitCount(FILENAME);
                } else {
                        digit = getHitCountOnly(FILENAME);
                }

                res.setContentType("text/html");
                toClient = new PrintWriter(res.getOutputStream(),true);

                toClient.println("<table border=0 cellpadding=0 cellspacing=0><tr>");
                for(int i = 0; i < MAX_DIGIT; i++)
                        toClient.println("<td><img src=http://hycedu.hanyang.ac.kr:1200/counter/"+digit[i]+".JPG border=0 vspace=0 hspace=0></td>");
                toClient.println("</tr></table>");
        }

        public void error_handling(Exception e, String msg) {
                System.err.println(msg);
                System.err.println(e);
        }

}

�� ҽ�� տ�� ۼ��ߴ� ī�� ҽ�� ణ �� Դϴ�. �� ¿�� Cookie �� Ͽ��, �� Ծ� �� ϰ��?

�� ī��ʹ� �� ī��Ϳ� �� ٸ��? ū ��̴� ��ϴ�. �ٸ� �ѹ� ��Դ� �� ٽ� �� 䱸 �ϴ��, �� ʴ´ٴ� �� Դϴ�. �� Ҹ��ĸ�, � �� , �� Cookie�� ϴ�. �׸�� ó�� Ƿ�, ī��Ʈ�� ø��, ȭ�鿡 �ѷ��ݴϴ�. �ٽ� �� , ��Ű�� Ȯ��Ͽ� �׻�� 湮�� ߴ� �� Ȯ��մϴ�. �׷�� , �� ī��Ʈ �� ׳� �ѷ��ֱ⸸ �ϴ� ��Դϴ�. �� ī��Ϳ�� ڰ� ��ͼ� Reload�� ī��Ʈ �� þ� ��, �̹� ī��ʹ� �þ� �� ʴ� ��. �ٸ� Cookie�� Default�� ߱� ��, �� ÿ� ��Ű�� ϴ�. �׷�� ٽ� �� ⵿��Ų�� ϸ� ī��Ʈ�� ˴ϴ�. �׷� �� ҽ�� м�� ڽ��ϴ�.

init �޼ҵ���

COOKIE_NAME = sc.getInitParameter("COOKIE_NAME");

�� ? �Ӹ� �ƴ϶� �� , String COOKIE_NAME�� ϴ�. �̰� Cookie�� Cookie�� ̸�� ˴ϴ�. Cookie�� ̸�� �ٴ� �� տ�� ߾��?--;

protected synchronized int[] getHitCountOnly(String filename)

�� ޼ҵ��Դϴ�. �� ߵ�� ̹� Cookie�� ִ� �� Count�� ø� �ʿ䰡 ��, �׳� �� Count�� о� ��̴µ� ��ϴ� �޼ҵ��Դϴ�. �� nc.class�� getHitCount() �޼ҵ�ʹ� ū ��̰� ��ϴ�. �ٸ� �� Ѽ� �ٽ� file �� writing�ϴ� �κи� �� ֽ��ϴ�.

protected synchronized int[] UpdateHitCount(String filename)

�� ޼ҵ��Դϴ�. �� ̰� ��׿�. nc.class��. �� о ��Ű�� ٽ� ��ϴ� �� Ǿ� �ֽ��ϴ�. �ο� �� ʿ� ��?

protected Cookie getCookie(HttpServletRequest req, String c_name)

�� ߿�� ޼ҵ尡 �ǰڳ׿�. Cookie�� �� method�Դϴ�. parameter�δ� HttpServletRequest�� String�� ޴±��. ��ڴ� �� ȵ�� ƽ� ��̰�, c_name�̶�� String�� ޾Ƶ�� Cookie�� ̸��Դϴ�. �׷�� ̸�� Cookie�� ã�Ƽ� �� Cookie�� return�ϵ�� մϴ�.

Cookie[] cookies = req.getCookies();

�� ϳ�� Cookie�� ִ� �� ƴϱ� ��, �޾ƿ�� Cookie�� ݵ�� 迭�� ޾Ƶ鿩�� մϴ�. �׷�� ޾Ƶ�� Cookie�߿�� ϴ� �� ã��ϴ�. ��Ű�� ̸�� ǹ��ϴ� ��.

Cookie[] cookies = req.getCookies();
if(cookies!=null) {
          for(int i=0; i < cookies.length; i++) {
                     if(cookies[i].getName().equals(c_name)) {
                                 return cookies[i];
                     }
          }
}

�� Cookie�� ִٸ�, �� Cookie�߿�� ̸�� Cookie�� ã�Ƽ� return��ŵ�ϴ�. �� ̻�� ο�� ʿ� ��?

public void setCookie(HttpServletResponse res, String c_name)

�� ޼ҵ�� ޾Ƶ�� c_name�� Cookie�� ϴ� �޼ҵ��Դϴ�. �̹�� ϴ� ��̴� �翬�� HttpServletResponse ��ü�� ޾Ƽ� �ؾ� �ϰ��? �׷��

Date date = new Date();
String visit = date.toString();
Cookie logged = new Cookie(c_name, visit);
res.addCookie(logged);

�� ð�� ̿��ؼ� Cookie�� res.addCookie(Cookie c)�� ޼ҵ带 �̿��ؼ� �� ݴϴ�. �� ʰ� ��Ͻ� �� ְ��? ��⼭, Cookie�� ð�� ߴµ�, �̰� �̿��ؼ� ��ڿ�� ̾��, �� ְ��? �Ǵ� ��ڸ� �Է��־ �� ° �湮�Դϴ� �� ְڳ׿�....*^^*

service �޼ҵ�� Cookie�� ִ�� Ȯ��ؼ� �� ޼ҵ带 ȣ�� ̿��ؼ� ȭ�鿡 �ѷ��ִ� �� մϴ�. �׷� �� ƽð��?

�� 1999 Lee Min Goo, All rights are reserved Last modified 1999.2
If you have any question, send mail to bluehope