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관리 메뉴

BASHA TECH

ch05-06 본문

Computer/JSP

ch05-06

Basha 2022. 8. 25. 18:00

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계산기 프로그램

src/main/java > ch05 > CalcServlet.java

src > main > java > ch05 > CalcServlet.java

package ch05;

import java.io.IOException;
import java.io.PrintWriter;

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

@WebServlet("/ch05/calc")
public class CalcServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public CalcServlet() {
		super();
	}

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		int n1 = Integer.parseInt(request.getParameter("n1"));
		int n2 = Integer.parseInt(request.getParameter("n2"));
		String op = request.getParameter("op");
		
		long result = 0;
		
		switch(op) {
			case "add":
				result = n1 + n2;
				break;
			case "sub":
				result = n1 - n2;
				break;
			case "mul":
				result = n1 * n2;
				break;
			case "div":
				result = n1 / n2;
				break;
		}
//		client 결과 보낸다. => response 사용
		response.setContentType("text/html; charset=utf-8"); // 이 위치에 정확히 있어야함 
		// utf-8로 인코딩하라고 먼저 선언.
		PrintWriter out = response.getWriter();
		out.println("<h2>계산기</h2><hr>");
		out.println("계산 결과: " + result);
	}

}

src > ch05 >calForm.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	<h2>계산기~</h2>
	<hr>
	<form action="calc" method="post">
		<input type="text" name="n1" size="10">
		<select name="op">
			<option value="add">+</option>
			<option value="sub">-</option>
			<option value="mul">x</option>
			<option value="div">/</option>
		</select>
		<input type="text" name="n2" size="10">
		<input type="submit" value="계산">
	</form>
</body>
</html>

Hello World

src/main/java > ch05 > HelloWorld.java

src > main > java > ch05 > HelloWorld.java

package ch05;

import java.io.IOException;
import java.io.PrintWriter;

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

@WebServlet("/hello01")
public class HelloWorld extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public HelloWorld() {
		super();
	}

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
//		한글 처리 => 첫 줄에 존재
		response.setContentType("text/html;charset=utf-8");
		PrintWriter out = response.getWriter();
		out.println("<!doctype html>");
		out.println("<html>");
		out.println("<head>");
		out.println("</head>");
		out.println("<body>");
		out.println("<h2>Hell World~! <h2>"); // 화면 담당은 jsp 처리담당은 servlet이~
		out.println("</body>");
		out.println("</html>");
	
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
	}

}

회원가입 프로그램

src/main/java > kr.co.big15 > LoginServlet.java

src > main > java > ch05 > kr > co > big15 > LoginServlet.java

package kr.co.big15;

import java.io.IOException;
import java.io.PrintWriter;

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;

/**
 * Servlet implementation class LoginServlet
 */
@WebServlet("/login/LoginServlet")
public class LoginServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	/**
	 * @see HttpServlet#HttpServlet()
	 */
	public LoginServlet() {
		super();
	}

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setContentType("text/html;charset=utf-8");
//		로그인 여부 확인 =>
		HttpSession session = request.getSession();
//		if (session.getAttribute("userid") == null) {
//			response.sendRedirect("loginForm.jsp");
//			return;
//		}
		
		
		String userid = request.getParameter("userid"); //request 들어있는 id 값을 추출
		String userpw = request.getParameter("userpw"); //request 들어있는 pw 값을 추출
		
//		id/pw 데이터 검증 (validation)
		if (userid.isEmpty() || userpw.isEmpty()) {
			response.sendRedirect("loginForm.jsp");
			return;
		}
			
//		getSession(true) : client가 가지고 있는 세션ID와 동일한 세션 object가 있으면 찾아서 주소값을 반환한다.
//																       없으면 생성한다.
//		getSession(false) : 새로 생성을 하지 않습니다.

		PrintWriter out = response.getWriter();
		
		
		// userid, userpw => DataBase select 처리
		if (userid.equals("hong")) {
			if (userpw.equals("1234")) {
		// userid, userpw 정상 입력 => 메인페이지 이동
		// session을 생성하고, session userid를 저장 => 메인페이지에서 userid 출력
				session.setAttribute("userid", userid);
				session.setAttribute("usernm", "홍길동");
				response.sendRedirect("../main.jsp");
			}else {
		// userpw 값이 잘못된 경우 처리할 코드	
				out.println("<script>alert('Password Error!'); history.back();</script>");
			}
		}else {
		// userid 값이 잘못된 경우 처리할 코드	
			out.println("<script>alert('ID Error!'); history.back();</script>");
		}
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

	}

}

src/main/java > kr.co.big15 > LogoutServlet.java

src > main > java > ch05 > kr > co > big15 > LogoutServlet.java

package kr.co.big15;

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("/LogoutServlet")
public class LogoutServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public LogoutServlet() {
		super(); 
	}

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
//		로그아웃 => Session 저장된 데이터 삭제
		HttpSession session = request.getSession(false);
//		session.removeAttribute("userid");
//		session.removeAttribute("usernm");
		if (session != null && session.getAttribute("userid") != null) {
			session.invalidate(); // 세션에 저장된 전체 데이터를 한번에 삭제
		}
		response.sendRedirect("./login/loginForm.jsp");
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
	}

}

src > main > webapp > login > loginForm.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>로그인</title>
</head>
<body>
	<div>
		<h2>로그인</h2>
		<form action="LoginServlet" method="get" name="form1">
			ID <input type="text" name="userid"><br>
			PW <input type="text" name="userpw">
			<input type="submit" value="login">
		</form>
	</div>
</body>
</html>

src > main > webapp > main.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>BIG15 메인</title>
</head>
<body>
	<h2>메인 페이지</h2>
	${usernm} 님 환영합니다! &nbsp; <a href="#">로그아웃</a>
	
</body>
</html>

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