프로그래밍/Java 공부

자바 Servlet - 세션 이용 로그인/ 로그아웃 기능

개발계발게발 2021. 7. 6. 16:53
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세션(session)

세션은 쿠키와 달리 저장할 데이터를 서버에 저장

 

 

세션 시작(세선을 사용하기 위해 세션 정보 리턴)

HttpSession session = request.getSesstion();

 

세션 저장

session.setAttribute("이름", 값);

 

저장된 세션 데이터 가져오기

String id = (String)session.getAttribute("id");

 

세션 삭제

session.removeAttribute("이름");

 

세선 종료

session.invalidate();

 

 

세션이용 로그인 기능 예제

 

loginAction.java(servlet 세션이용 예제)

package com.knowhoon.web;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.knowhoon.dao.LoginDAO;
import com.knowhoon.dto.LoginDTO;

@WebServlet("/loginAction")
public class LoginAction extends HttpServlet {
	private static final long serialVersionUID = 1L;
      						//UUID
    public LoginAction() {
        super();
    }
			//get방식 요청
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//한글처리
		response.setContentType("text/html;charset=UTF-8");
		
		String id = request.getParameter("id");
		String pw = request.getParameter("pw");

		LoginDAO dao = new LoginDAO();
		LoginDTO dto = new LoginDTO();
		dto.setId(id);
		dto.setPw(pw);
		LoginDTO result = dao.loginAction(dto);
	
		if(result != null && result.getName()!=null){			
			session.setAttribute("id", result.getId());
			session.setAttribute("name", result.getName());
			session.setAttribute("no", result.getNo());
			System.out.println(session.getAttribute("id"));
			System.out.println(session.getAttribute("name"));
			System.out.println(session.getAttribute("no"));
			response.sendRedirect("./board.jsp");
		
		}else{
			System.out.println("로그인 해주세요");		
			response.sendRedirect("./index.jsp");
		}		
	}
}

 

logout.java(servlet 세션이용 예제)

package com.knowhoon.web;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

@WebServlet("/logout")
public class Logout extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    public Logout() {
        super();
    }
    
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//response.getWriter().append("Served at: ").append(request.getContextPath());
		System.out.println("get");
		HttpSession session = request.getSession();
		if(session.getAttribute("id") != null) {
			session.removeAttribute("id");			
		}
		if(session.getAttribute("name") != null) {
		session.removeAttribute("name");
		}
		//session.invalidate(); //모든 세션 종료
		response.sendRedirect("./index.jsp");
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		System.out.println("post");
	}
}

 

 

 

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>index.jsp</title>

</head>	<!-- /loginAction 서블릿으로 전송
		java + web -> servlet
		java코드 속에 html코드
		서블릿 2.5이후 기술은 그냥 사용
		서블릿 2.5이전 기술은 web.xml에 설정을 적용
		
		
		html + java
		html코드 속에 자바
		 -->
<%@ include file="./menu.jsp"%>
<div id="loginbox">
	<div id="loginimg">
		<img alt="" src="./login.png">
	</div>
	<div id="logininput">

		<form action="./loginAction" method="post">
			<input type="text" name="id" maxlength="15" placeholder="아이디를 입력하세요"
				required="required"> <input type="password" name="pw"
				maxlength="20" placeholder="비밀번호를 입력하세요" required="required"><br>
			<button type="submit">LOGIN</button>
			<button type="reset">RESET</button>
		</form>
	</div>

</div>

</body>
</html>

 

LoginDAO.java

package com.knowhoon.dao;
 
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
 
import com.knowhoon.dto.LoginDTO;
import com.knowhoon.db.DBConnection;
 
public class LoginDAO {
	public LoginDTO loginAction(LoginDTO dto) {
		LoginDTO login = new LoginDTO();
		Connection conn = DBConnection.dbConnection();
		ResultSet rs = null;
		PreparedStatement pstmt = null;
		
		String query = "SELECT * FROM login WHERE id=? AND pw=?";
	
		try {
			pstmt = conn.prepareStatement(query);
			pstmt.setString(1, dto.getId());	//물음표 위치에 어떤 값
			pstmt.setString(2, dto.getPw());	//적어주기 (위치, 값)
			rs = pstmt.executeQuery();
			if(rs.next()) {
				login.setNo(rs.getInt("no"));
				login.setName(rs.getString("name"));
				login.setId(rs.getString("id"));
				login.setPw(rs.getString("pw"));
				login.setEmail(rs.getString("email"));				
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}finally {
			try {
				if(rs != null) {rs.close(); }
				if(pstmt != null) {pstmt.close(); }
				if(conn != null) {conn.close(); }
			} catch (SQLException e) {
				e.printStackTrace();
			}			
		}		
		return login;		
	}	
}

 

LoginDTO.java

package com.knowhoon.dto;

//no, id, pw, name, email
public class LoginDTO {
	private int no;
	private String id, pw, name, email;
 
	public String getId() {
		return id;
	}
 
	public void setId(String id) {
		this.id = id;
	}
 
	public String getPw() {
		return pw;
	}
 
	public void setPw(String pw) {
		this.pw = pw;
	}
 
	public String getName() {
		return name;
	}
 
	public void setName(String name) {
		this.name = name;
	}
 
	public String getEmail() {
		return email;
	}
 
	public void setEmail(String email) {
		this.email = email;
	}
 
	public int getNo() {
		return no;
	}
 
	public void setNo(int no) {
		this.no = no;
	}
		
}

 

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