L07 쿠키로 값 전달

2016. 10. 27. 17:49ㆍProgramming/JSP

**배운 것**


1) 쿠키 생성

Cookie c = new Cookie("id", "jspLesson");


2) 유효시간 설정 후 쿠키에 저장

c.setMaxAge(365*24*60*60); //1년 = 일*시*분*초

response.addCookie(c);


3) 쿠키 메소드

setPath():  쿠키 사용의 유효 디렉토리 설정

setVersion(): 쿠키 버전 설정

getName(): 쿠키 이름 얻기

getValue(): 쿠키 값 얻기


4) 첫 방문/아닌 경우 분기(if) 만들어

lastTime(방문 시간) 쿠키에 저장





<index.jsp: 메인 화면>




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<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
 "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Cookie에 대해 알아보자</title>
</head>
<body>
           <h1>쿠키를 설정하고 불러오자</h1>
           <hr>
           <h3><a href="./L01SetCookie.jsp">쿠키 설정하기</a></h3>
           <h3><a href="./L02GetCookie.jsp">쿠키 가져오기</a></h3>
           <h3><a href="./L03RemoveCookie.jsp">쿠키 삭제하기</a></h3>
           <h3><a href="./L04LastDate.jsp">접속한 마지막 날짜 알아보기</a></h3>
</body>
</html>
 
cs



<L01SetCookie.jsp>


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<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>쿠키 설정</title>
</head>
<body>
           <h1>쿠키 설정</h1>
           <%
           //쿠키는 브라우저에 저장되는 객체(마치 파일처럼)
           //세션과 달리 브라우저 꺼져도 남아 있음(but 시간 지나면 사라짐)
           //쿠키를 생성하고 response 객체에 담으면 저장 완료
           
           Cookie c = new Cookie("id", "jspLesson");//생성과 동시에 파라미터 저장
           Cookie c2 = new Cookie("pw", "admin1234");
           Cookie c3 = new Cookie("name", "ckm");
           
           //만약 유효시간 설정 안 하면 브라우저 종료시 삭제됨
           c.setMaxAge(365*24*60*60); //1년 = 일*시*분*초
           response.addCookie(c);
           response.addCookie(c2);
           response.addCookie(c3);
           out.print("<h3>설정완료</h3>");
           %>
</body>
</html>
 
cs




<L02GetCookie.jsp>




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<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
 "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>쿠키 가져오기</title>
</head>
<body>
           <h1>쿠키 가져오기</h1>
           <%
           Cookie[] cookies = request.getCookies();
           for(int i=0; i<cookies.length; i++){  
                      out.print("<h3>"+cookies[i].getName()+":"+cookies[i].getValue()+"<h3>");
           
           //다른 방식        
           //for(Cookie cookie : cookies){
           //out.print("<h3>"+cookie.getName()+":"+cookie.getValue()+"<h3>");
           }
           
           %>
           <hr>
           <h3>세션아이디: <%=session.getId()%></h3>
           <!--클라이언트가 최초 접속시 session과 cookie가 생성되는데 쿠키는 세션 아이디를 가짐-->
           <h3>쿠키는 웹사이트에 접속할 때 생성되는 정보를 담는 임시 파일이다.</h3>
           <h3>일반적으로 4kb 이하의 크기로 생성된다.</h3>
           <h3>쿠키의 원래 목적은 사용자의 정보를 유지시키고 접속시 바로 로그인되도록 하기 위해</h3>
           
           <h3>쿠키의 단점</h3>
           <h3>1. 쿠키는 요청(request)에 포함되기 때문에 쿠키가 많으면 요청이 느려짐</h3>
           <h3>2. 세션은 유지, 쿠키는 저장 -> 보안은 세션이 좋다.</h3>
</body>
</html>
 
cs





<L03RemoveCookie.jsp>


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<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
 "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>쿠키 삭제</title>
</head>
<body>
           <h1>쿠키의 maxAge를 0으로 만들어서 삭제</h1>
           <%
           Cookie[] cookies = request.getCookies();
           for(Cookie a : cookies){ //[뽑을 데이터타입] [변수명]: [배열명]      
                      a.setMaxAge(0);
                      response.addCookie(a);
                      //response는 서버에서 클라이언트에 보내는 최종 응답
                      //page가 모두 loading 될 때 응답이 완료됨
           }
           %>
           <h1>삭제 완료</h1>
</body>
</html>
 
cs




<L03RemoveCookie.jsp:첫 방문>


<L03RemoveCookie.jsp:첫 방문 아닌 경우>



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<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"
    import ="java.util.Date, java.text.SimpleDateFormat"
    %>
    
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>마지막 방문일을 알아보자</title>
</head>
<body>
           <h1>lastDate 쿠키를 만들어서 방문일을 담자</h1>
           <%
                      Cookie lastDate = null;
                      String nowDate = ""+System.currentTimeMillis();
                      //cookie의 value로 문자열을 저장하기 위해
                      //lastDate라는 쿠키가 없으면 최초 방문 -> lastDate 쿠키를 만든다.
                      //최초 방문이면 "처음 방문입니다." 라는 메시지를 출력
                      //최초 방문이 아니면 언제 접속했는지 lastDate를 출력

                      //활용 예
                      //1) 오랜만에 접속시 비밀번호를 바꾸게 한다.
                      //2) 강의 페이지 -> 접속하지 않으면 여러 가지 메시지
                      
                      Cookie[] cookies = request.getCookies();
                      if (cookies != null) {
                                 for (Cookie a : cookies) {
                                            if(a.getName().equals("lastDate")){
                                                       lastDate = a; //최초 방문이 아님
                                            }
                                 }
                      }
                      //첫 방문인 경우(일단 출력 후 현재시간(nowDate) 쿠키에 저장)
                      if(lastDate==null){
                                 out.print("<h3>처음 방문입니다.</h3>");
                                 lastDate = new Cookie("lastDate", nowDate);
                                 lastDate.setMaxAge(365*24*60*60);
                                 response.addCookie(lastDate);

                      //첫 방문 아닌 경우
                      }else{
                                 
                                 //문자열 -> long type으로 변경
                                 long conv = new Long(lastDate.getValue()).longValue();
                                 Date date = new Date(conv);
                                 //Date에서 년월일시분 추출
                                 SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
                                 out.print(sdf.format(date));
                                 //마지막 방문일 업데이트
                                 lastDate.setValue(nowDate);
                                 response.addCookie(lastDate);
                      }
           %>
</body>
</html>
 

cs








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