Wed/Jan/22 [Java] day17. 실습_방명록

Study/2020 국비교육_Java 2020. 1. 22. 10:06

Wed/Jan/22

[Java] day17.

실습_방명록

서버 server 개념별 분류

- SW : Tomcat..

- HW : Xenom...

주소는 원래 서버의 고정 IP 주소인데, Domain 부여

일반적으로는 변동 ip 주소 사용 - 한정된 자원, broadband 업체에서 보유한 ip list 중 하나를 사용할 때 마다 할당하는 것

어제 실습한 내용 정리

Web Brower - Web Application - Web Serber - JDBC - mySQL DB

이 구조를 반드시 명확하게 알고 넘어가야, 추후에 Spring 이 편하다

Web Application

Board
- Web Content : index.html, list.jsp, write_form, write, detail_form, modify, modify_form, hit.jsp 등
- Java : DBClass ( selectAll, update, insert 등 method), ChangeEncodeClass

mySQL DB : board_db > board_table > idx, hit contents, write,...

Web Browser

HTTP hyper text transper protocol
HTTPS hyper text transper protocol secret ; 보안 설정된 protocol
HTML hyper text markup language
FTP file transfer protocol

Web 주소 구성

http : // localhost:8080/board/index.html

http - internet
localhost:8080 : 서버 주소 : 포트
board : project
index.html.. : 요청파일
엔터를 누르면 요청

※ ERROR MESSAGE

404
- 서버가 구동하지 않는 경우 : Tomcat
- 파일 경로가 잘못된 경우 ; 대소문자도 구별
- 파일이 없는 경우
500 : 내부 코드 오류

null pointer error는 반드시 웹 주소가 어떻게 되어있는지 자세히 확인! 특히 공백 여부 확인

브라우저는 <!DOCTYPE HTML> ~~~ </HTML>까지 BufferedReader 방식으로 읽어서 compiling

HTML5.0 방식, 그 이전 방식의 file type은 동일, compiler는 별도 → browser가 코드를 읽으면서 어떤 compiler를 구동할 건지 결정, 특히 <!DOCTYPE HTML 뒤에 5.0 이전 스타일인지 확인>

HTML / CSS / JavaScript 모두 Brower compile

JSP 는 Tomcat server 에서 compile! compiling 순서

Tomcat에서 ***.jsp.java
***.jsp.class > object 생성 ; 이때 오류가 나면 browser로 error msg 전송

Data Flow

순서	program	file
1	HTML	index.html	<a href = "write_form.jsp"> 글쓰기 </a>	href = link로 이동/요청
2	JSP	write_form.jsp	<%@ page *** %>	<%에 빨간 줄 가는 경우 == servlet에서 인식 못해서, 작동만 잘되면 상관 없음
			<form action = "write.jsp" method = "get"> </form>	form tag 중요
			<input type = "text" name = "***">	여기서 name은 server로 전송되는 parameter
			<input type = "submit" value = "***">	submit form tag 안의 모든 value들을 action에 지정한 파일로 전송
			<input type = "reset" value = "***">	reset form tag 안의 모든 입력값을 초기화
			따라서 submit과 reset은 반드시 form tag 안에 위치해야 함
3	Tomcat server		write_form.jsp → write_form.jsp.java → write_form.jsp.class → object 생성 HTML 형태로 compiling
4	HTML	write_form.jsp	화면 출력 http://~~~~/write.jsp?write=*&title=&contents=**
submit으로 입력된 values 전송
5	JSP	write.jsp	data가 "writer", "title", "contents" parameter로 전송됨 → getParameter("writer") 이걸 요청request 하기 때문에 → request.getParameter("writer") 이 value의 type은 String → String w = request.getParameter("writer")
6	JDBC	입력값 전송 → mySQL	Class.forName(driver_manager) connection = DriverManager.getConnection(db_url, db_id, db_pw) DBClass.dataInsert(writer, title, contents) method 호출해서 입력
7	JAVA	DBWriteClass	dataInsert(writer, title, contents) method int n = conn.createStatemet.executeUpdate("insert into board_table (writer, title, contents) values ('writer','title','contents'") status = (n>0) true : false ; * writer/title/content 모두 require를 안걸어놓았을때, null 값이 입력되지 않게 하려면 if(w==null&&t==null&&c==null) out.print("err")
8	JSP	Write.jsp	위에서 true 값이 나왔는지 확인, 이에 대해 반응/응답 response 해서 Redirect if (status==true) response.sendRedirect(list.jsp);

실습_

입력/수정/삭제 가능한 방명록 만들기

1. 구조

main.jsp	main page 버튼 : list로 이동 (onclick = "location.href = 'vlist.jsp'")
vlist.jsp	방명록 : 번호 no / 내용(if(context.length>20) 20글자 substring (0,20) +...// else ) / 작성자 writer 버튼 : 방명록 쓰기, 방명록 삭제
write_form.jsp	방명록 쓰기 : 비밀번호pw, 작성자writer, 내용context, 저장, 취소
write.jsp	mySQL table에 values 입력 성공 시 vlist.jsp로 이동 : if(status==true) response.sendRedirect("vlist.jsp")
mySQL	no int not null auto_increment // writer varchar(30) not null // content text not null// pw varchar(20) not null

2. mySQL table 생성

mysql> create table list (
    -> no int primary key not null auto_increment,
    -> writer varchar(30) not null,
    -> content text not null,
    -> pw varchar(20) not null);

mysql> desc list;
+---------+-------------+------+-----+---------+----------------+
| Field   | Type        | Null | Key | Default | Extra          |
+---------+-------------+------+-----+---------+----------------+
| no      | int(11)     | NO   | PRI | NULL    | auto_increment |
| writer  | varchar(30) | NO   |     | NULL    |                |
| content | text        | NO   |     | NULL    |                |
| pw      | varchar(20) | NO   |     | NULL    |                |
+---------+-------------+------+-----+---------+----------------+

3. ChangeEcode.class 생성

4. DB.class 생성

package com.wjh.guest;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DB {
	
	public DB(){
		
	}
	
	static Connection conn = null;
	
	public static void dbCon(){
		
		String driver_name = "com.mysql.jdbc.Driver";
		String db_url = "jdbc:mysql://localhost:3306/vlist";
		
		try {
			Class.forName(driver_name);
			System.out.println("SUCCESS_Driver Loading");
			
			conn = DriverManager.getConnection(db_url, "root", "1234");
			System.out.println("SUCCESS_DB_Connection");
			
		} catch (ClassNotFoundException e) {
			System.out.println("ERR_Driver_Loading : "+e.getMessage());
		} catch (SQLException e) {
			System.out.println("ERR_DB_Connection : "+e.getMessage());
		}
		
	}  // dbCon()
	
	public static boolean dataInsert(String w, String t, String p) {
		
		dbCon();
		boolean status = false;
		try {
			int n = conn.createStatement().executeUpdate("insert into list (writer, content, pw) values('"+ChangeEncode.toLatin(w)+"','"+ChangeEncode.toLatin(t)+"','"+ChangeEncode.toLatin(p)+"')");
			// insert into list (writer, content, pw) values('w','t','p');
			status =(n>0)? true : false;
		} catch (SQLException e) {
			System.out.println("ERR_dataInsert : "+e.getMessage());
		} finally{
			try {
				conn.close();
			} catch (SQLException e) {
				System.out.println("ERR_dataInsert_finally : "+e.getMessage());
			}
		}
		return status;
		
	}	// dataInsert()
	
	
	public static ResultSet showAll(){
		dbCon();
		ResultSet rs=null;
		
		try {
			rs = conn.createStatement().executeQuery("select * from list order by no desc");
			return rs;
		} catch (SQLException e) {
			System.out.println("ERR_dataInsert : "+e.getMessage());
			return null;
		}	
		
		
	}	// showAll
	
	public static ResultSet showOne(String num){
		dbCon();
		ResultSet rs = null;		
		try {
			rs = conn.createStatement().executeQuery("select * from list where no = "+num);
			return rs;
		} catch (SQLException e) {
			System.out.println("ERR_showOne : "+e.getMessage());
			return null;
		}
		
	}
	
	public static boolean delOne(String num) {
		dbCon();
		boolean status = false;
		try {
			int	n = conn.createStatement().executeUpdate("delete from list where no = "+num);
			status =(n>0) ? true : false;
						
		} catch (SQLException e) {
			System.out.println("ERR_delOne : "+e.getMessage());
		} finally{
			try {
				conn.close();
			} catch (SQLException e) {
				System.out.println("ERR_delOne_finally : "+e.getMessage());
			}
		}
		return status;
		
	}	// delOne
	
	public static boolean updateOne(String num, String writer, String content){
		dbCon();
		boolean status = false;
		try {
			int n = conn.createStatement().executeUpdate("update list set writer = '"+ChangeEncode.toLatin(writer)+"', content = '"+ChangeEncode.toLatin(content)+"' where no = "+num);
			status = (n>0)? true : false;
		} catch (SQLException e) {
			System.out.println("ERR_updateOne : "+e.getMessage());
		} finally{
			try {
				conn.close();
			} catch (SQLException e) {
				System.out.println("ERR_updateOne_finally : "+e.getMessage());
			}
		}
		return status;
	}	// updateOne

	
}	// DB Class

jsp 페이지 구성

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>


<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Main</title>
</head>
<body bgcolor = #fffeb3>

<h1><font color = #fb2e01>Hello, World!</font></h1>
어서오세여~
<p>

<input type = "button" value = "방명록" onclick = "location.href='vlist.jsp'" /> 쓰러가기!

</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>

<%@ page import="com.wjh.guest.DB, com.wjh.guest.ChangeEncode, java.sql.SQLException, java.sql.ResultSet" %>

<% 
String no = null;
String writer = null;
String text = null;

ResultSet rs = DB.showAll(); 
rs.beforeFirst();

%>

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Visitor List</title>
</head>
<body bgcolor = #fffeb3>

<h2><font color = #fb2e01>방명록입니다!</font></h2>

<table border = 5 >

<tr>
<th >몇 번째</th>	<th>누가</th>	<th>무슨 말을 남겼나</th>
</tr>

<%

while(rs.next()) { 
	
	no = rs.getString("no");
	writer = rs.getString("writer");
	if(writer.length()>10)	writer = writer.substring(0,10) + "...";
	
	text = rs.getString("content");
	if(text.length()>20) text = text.substring(0,19)+"...";
%>
<tr>
<td><%=no%></td>	<td><%=ChangeEncode.toUnicode(writer)%></td>	
<td><a href="detail.jsp?no=<%=no%>"><%=ChangeEncode.toUnicode(text)%></a></td>
</tr>
<%} %>

</table>
<p>
<input type = "button" value = "나도 쓸래" onclick = "location.href='write_form.jsp?'"><p>
<input type = 'button' value = "MAIN" onclick="location.href='main.jsp'">


</body>
</html>

write_form.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>

<%@ page import="com.wjh.guest.DB, java.sql.SQLException, java.sql.ResultSet,
com.wjh.guest.ChangeEncode" %>

<% 

%>

<!DOCTYPE html>

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Write</title>
</head>
<body bgcolor = #fffeb3>

<h2><font color = #fb2e01>방명록을 남겨주세요~</font></h2>

<form action="write.jsp" method = get>

<table>
<tr>
<td>작성자</td><td><input type = text size = 47 name = "writer" placeholder = "이름을 적어주세요" required = "required" /></td>
</tr>

<tr>
<td>내용</td><td><textarea cols = 50 rows = 15 name = "content" required = "required" placeholder = "바르고 고운말로 써주세여" ></textarea></td>
</tr>

<tr>
<td>비밀번호</td><td><input type = "password" name = pw size = 20  required = "required" /> </td>
</tr>
</table>
20byte 이내로 작성해주세요

<p>
<input type = 'reset' value = "다시쓰기">
<input type = "button" value = "글목록 돌아가기" onclick="location.href='main.jsp'">
<input type = "submit" value = "작성완료!" onclick="location.href='write.jsp'">

</form>
</body>
</html>

write.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
   
<%@ page import="com.wjh.guest.DB, java.sql.SQLException, java.sql.ResultSet,
com.wjh.guest.ChangeEncode" %>

<% 
String writer = request.getParameter("writer");
String text = request.getParameter("content");
String pw = request.getParameter("pw");

boolean status = DB.dataInsert(writer, text, pw);
//(writer, content, pw)
	if(status==true) {
		response.sendRedirect("vlist.jsp");
	}
%>

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@
page import = "com.wjh.guest.DB, com.wjh.guest.ChangeEncode, java.sql.ResultSet, java.sql.SQLException"
%>
<%
ResultSet rs = DB.showOne(request.getParameter("no"));
String no = null;
String writer = null;
String text = null;
String pw = null;

rs.beforeFirst();
while(rs.next()) {
	no =rs.getString("no");
	writer = rs.getString("writer");
	text = rs.getString("content");
	pw = rs.getString("pw");
}

String type = "";
%>
<!DOCTYPE>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Detail</title>
</head>
<body bgcolor = #fffeb3>

<h1><font color = #fb2e01><%=no%>번 글의 디테일을 보여줍니다</font></h1>

<table border = 1>

	<tr><td>누가</td><td><%=ChangeEncode.toUnicode(writer)%></td></tr>
	<tr><td>뭐라고했게요</td><td><%=ChangeEncode.toUnicode(text)%></td></tr>

</table>

<p>
<form action = "pw_check.jsp" method = "get" >
<table border = 1>

	<tr>
	<td>비밀번호 입력</td>
	<td>
	<input type = "hidden" size = 20 readonly = "readonly" name = "no" value = <%=no%>>
	<input type = "password" name = "pw"><p>
	<input type = 'radio' value = 'renew' name = "type" checked> 다시쓰기
	<input type = 'radio' value = 'delete' name = "type" checked> 글삭제<p>
	<input type = "submit" value = "가즈아" onclick = "location.href = 'pw_check.jsp">
	</td>
	</tr>
	
</table>
</form>

<p>

<input type = "button" value = "잘봤습니다" onclick = "location.href = 'vlist.jsp'"/>
<input type = "button" value = "MAIN으로" onclick = "location.href = 'main.jsp'"/>

</body>
</html>

rewrite_form.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ 
page import="com.wjh.guest.ChangeEncode, com.wjh.guest.DB, java.sql.SQLException, java.sql.ResultSet"
%>

<%
String no = request.getParameter("no");
String writer = null;
String text = null;

ResultSet rs = DB.showOne(no);
rs.beforeFirst();
while(rs.next()){
	writer = ChangeEncode.toUnicode(rs.getString("writer"));
	text = ChangeEncode.toUnicode(rs.getString("content"));	
}
%>

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Renew</title>
</head>
<body bgcolor = #fffeb3>

<h1><font color = #fb2e01><%=no%>번 글을 다시 써봅시다</font></h1>
<form action = rewrite_check.jsp method = 'get'>
<table>

<tr>
<td>누가</td>	
<td><input type = hidden name = no value = <%=no%>>
<input type = text size = 20 name = "writer" placeholder = "<%=writer%>" required = "required" /></td>

</tr>

<tr>
<td>다른<br>말로</td>
<td><textarea cols = 21 rows = 10 name = content placeholder = "내용을 다시 써봐용" required = "required"  /><%=text%></textarea></td>
</tr>


<tr>
<td>다쓰셨으면..</td>	<td><input type = "submit" value = "작성완료!" onclick="location.href='rewrite_check.jsp'">
</td>
</tr>

<tr>
<td>다시쓰고 싶으면..</td>	<td><input type = 'reset' value = "초기화!!"></td>
</tr>

<tr>
<td>귀찮으면..</td>	<td><input type = 'button' value = "백투더 리스트!" onclick="location.href='vlist.jsp'"></td>
</tr>

</table>
</form>
</body>
</html>

pw_check.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>

<%@
page import = "com.wjh.guest.DB, com.wjh.guest.ChangeEncode, java.sql.SQLException, java.sql.ResultSet"
%>

<%
String pw = request.getParameter("pw");
String no = request.getParameter("no");
String type = request.getParameter("type");

ResultSet rs = DB.showOne(no);
rs.first();
String real_pw = rs.getString("pw");

if((type!=null)&&(no!=null)&&(pw!=null)&&real_pw.equals(pw)) {
	if(type.equals("delete")) 	response.sendRedirect("delete_check.jsp?no="+no);
	else response.sendRedirect("rewrite_form.jsp?no="+no);
} else response.sendRedirect("error.jsp"); 

%>

rewrite_check.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
   
<%@ page import="com.wjh.guest.DB, java.sql.SQLException, java.sql.ResultSet,
com.wjh.guest.ChangeEncode" %>

<% 
String num = request.getParameter("no");
String writer = request.getParameter("writer");
String text = request.getParameter("content");

if( (num==null) || (writer==null) || (text==null)) response.sendRedirect("error.jsp");

%>

<!DOCTYPE html>

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Write Check</title>
</head>
<body bgcolor = #fffeb3>

<h2><font color = #fb2e01><%=num%>번 글 다시 작성한 내용을 확인합니다</font></h2>


<table border = 1>
<tr><td>누가</td>	<td><%=request.getParameter("writer")%></td></tr>
<tr><td>뭐라썼나</td>	<td><%=request.getParameter("content")%></td></tr>
</table>

<p>
<form action = "rewrite_order.jsp" method = "get">
<input type="hidden" name = "no" value = <%=num%>>
<input type="hidden" name = "writer" value = <%=writer%>>
<input type="hidden" name = "content" value = <%=text%>>
<input type = "submit" value = "최종확인완료!" onclick="location.href = 'rewrite_order.jsp'">
<input type = "button" value = "취소하고 목록으로..." onclick="location.href = 'vlist.jsp'">
</form>

</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>ERROR</title>
</head>
<body>
<h1>ERROR</h1><p>
뭔가 잘못 입력했어요...;; 

<p>
<input type = "button" value = "MAIN" onclick = "location.href = 'main.jsp'"/>
<input type = "button" value = "LIST" onclick = "location.href = 'vlist.jsp'"/>

</body>
</html>

delete.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%
String no = request.getParameter("no");
%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>DELETE</title>
</head>
<body bgcolor = #fffeb3>

<h1><font color = #fb2e01>진짜 지울까여?</font></h1>

<%

out.print(request.getParameter("no")+"번 글을 지웁니다!");

%>
<p>
<input type = "submit" value = "지운다!" onclick = "location.href='delete.jsp?no=<%=no%>'"/>
<p>
<input type = "button" value = "글목록 돌아가기" onclick = "location.href='vlist.jsp'"/>

</body>
</html>

delete_check.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>

<%@
page import = "com.wjh.guest.DB, com.wjh.guest.ChangeEncode, java.sql.SQLException, java.sql.ResultSet"
%>

<%
String pw = request.getParameter("pw");
String no = request.getParameter("no");
String type = request.getParameter("type");

ResultSet rs = DB.showOne(no);
rs.first();
String real_pw = rs.getString("pw");

if((type!=null)&&(no!=null)&&(pw!=null)&&real_pw.equals(pw)) {
	if(type.equals("delete")) 	response.sendRedirect("delete_check.jsp?no="+no);
	else response.sendRedirect("rewrite_form.jsp?no="+no);
} else response.sendRedirect("error.jsp"); 

%>

<end>

저작자표시 비영리 동일조건 (새창열림)

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