JSP(상품재고관리 프로그램)

JSP

JSP(상품재고관리 프로그램)_2024-09-04

앵보몬 2024. 9. 5. 09:42

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이 JSP 페이지는 상품 정보를 조회하고, 상품을 추가하기 위한 폼을 제공하는 내용을 담고 있습니다. 코드의 주요 기능과 수정할 점은 다음과 같습니다.

주요 기능
① 상품 정보 조회 : 데이터베이스에서 상품 정보를 조회하고 이를 HTML 테이블에 출력합니다.

② 상품 추가 폼 : 상품 정보를 입력할 수 있는 폼을 제공합니다. 이 폼은 GET 메서드를 사용하여 데이터를 전송합니다.

개선 사항 및 주의사항

① JSP에서 Java 코드 최소화 : JSP 페이지에서 Java 코드를 직접 사용하는 것은 유지보수와 테스트를 어렵게 만들 수 있습니다. 가능한 경우 JSP는 HTML과 JSTL 또는 EL(Expression Language)만 사용하는 것이 좋습니다. 비즈니스 로직은 서블릿이나 서비스 클래스로 분리하는 것이 좋습니다.

② 데이터베이스 연결 관리 : JDBConnect 클래스에서 데이터베이스 연결과 쿼리 실행을 직접 처리하는 것은 좋지 않습니다. 데이터베이스 연결은 커넥 션 풀을 사용하는 것이 좋습니다. 또한, JDBConnect 클래스가 Statement와 Connection 객체를 직접 다루는 것도 지양해 야 합니다.

③ 문자 인코딩 : EUC-KR 대신 UTF-8을 사용하는 것이 더 범용적이고 표준입니다. EUC-KR은 특정 지역에서만 사용되며, UTF-8은 다양한 언어를 지원합니다.

④ 폼 액션 및 경로 : 폼의 action 속성이 "/JSP/products"로 되어 있는데, 이 경로가 실제로 존재하는지 확인하세요. 이 경로는 JSP 페이지가 있는 경로인지 확인할 필요가 있습니다. 또한, 상품 추가 폼의 경우, POST 메서드를 사용하는 것이 좋습니다. GET 메서드는 URL에 데이터가 노출되므로 보안상 안전하지 않습니다.

⑤ 리소스 누수 방지 : 데이터베이스 연결과 같은 리소스는 finally 블록에서 닫아야 합니다. rs와 jdbc.con을 닫는 코드가 있지만, jdbc.stmt도 닫는 것이 좋습니다.

DB

create table products (
    product_id number(4) primary key,
    product_name varchar2(20) not null,
    category varchar2(20),
    price number(10, 2),
    description varchar2(20),
    stock_quantity number(10, 2)
    );
   
insert into products values (1, '아이폰 15', '스마트폰', 1500000, '최신 스마트폰', 52000);
insert into products values (2, '삼성 갤럭시 s24', '스마트폰', 1400000, '고성능 스마트폰', 62000);
insert into products values (3, '맥북 프로 14', '노트북', 2500000, '고급형 노트북', 52000);
insert into products values (4, '삼성 노트북', '노트북', 1800000, '가성비 노트북', 62000);
insert into products values (5, '에어팟 프로 2세대', '이어폰', 350000, '무선 노이즈캔슬링 이어폰', 62000);
COMMIT;

select * from products;

main.jsp

<%@page import="java.sql.SQLException"%>
<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.Statement"%>
<%@page import="common.JDBConnect"%>
<%@ taglib prefix="c" uri="jakarta.tags.core" %>  
<%@ page language="java" contentType="text/html; charset=EUC-KR"
    pageEncoding="EUC-KR"%>
<!DOCTYPE html>
<html>
  <head>
    <meta charset="EUC-KR" />
    <title>상품재고관리</title>
  </head>
  <body>
    <h2>상품정보</h2>
    <hr>
    <form action="/JSP/products" method="get"><button type="submit">새로고침</button></form>
    <table border="1">
       <tr>
         <th>상품아이디</th>
         <th>상품명</th>
         <th>카테고리</th>
         <th>가격</th>
         <th>비고</th>
         <th>재고수량</th>
         <th>삭제</th>
         <th>수정</th>
       </tr>
   <c:forEach items="${products}" var="products">
      <tr>
         <td>${products[0]}</td>
         <td>${products[1]}</td>
         <td>${products[2]}</td>
         <td>${products[3]}</td>
         <td>${products[4]}</td>
         <td>${products[5]}</td>
         <td><button onclick="deleteProduct(${products[0]})">삭제</button></td>
          <td><button type="button" onclick="modifyProduct('${products[0]}', '${products[1]}', '${products[2]}', '${products[3]}', '${products[4]}', '${products[5]}')">수정</button></td>
      </tr>  
   </c:forEach>
   </table>
    <h2>상품추가 및 수정</h2>
    <hr>
    <form method="post" action="/JSP/insert">
       <label>아이디:</label>
       <input type="text" name="product_id"><br>
       <label>상품명:</label>
       <input type="text" name="product_name"><br>
       <label>카테고리:</label>
       <input type="text" name="category"><br>
       <label>가격:</label>
       <input type="text" name="price"><br>
       <label>비고:</label>
       <input type="text" name="description"><br>
       <label>재고:</label>
       <input type="text" name="stock_quantity"><br>
       <input type="submit" value="등록">
       <%-- <button type="button" onclick="updateProduct();">수정</button> --%>
       <input type="submit" onclick="updateProduct()" value="수정">
    </form>
       
    <script>
    function deleteProduct(product_id) {
        if (confirm("정말 삭제하시겠습니까?")) {
            var form = document.createElement("form");
            form.method = "POST"
            form.action = "/JSP/delete";
            var input = document.createElement("input");
            input.type = "hidden";
            input.name = "delete_id";
            input.value = product_id;
            form.appendChild(input);
            document.body.appendChild(form);
            form.submit();
        }
    }
   

    function modifyProduct(product_id, product_name, category, price, description, stock_quantity) {
        document.querySelector('input[name="product_id"]').value = product_id;
        document.querySelector('input[name="product_name"]').value = product_name;
        document.querySelector('input[name="category"]').value = category;
        document.querySelector('input[name="price"]').value = price;
        document.querySelector('input[name="description"]').value = description;
        document.querySelector('input[name="stock_quantity"]').value = stock_quantity;
      }
   
         function updateProduct() {
                if (confirm("정말 수정하시겠습니까?")) {
                //<form> 태그의 name 속성으로 <form>태그 객체를 받아온다.
                var myForm = document.myForm;

                //<form>태그 내 <input>태그의 속성으로 입력한 ID와 비밀번호를 받아온다
                var product_id = myForm.product_id.value;
                var product_name = myForm.product_name.value;
                var category = myForm.category.value;
                var price = myForm.price.value;
                var description = myForm.description.value;
                var stock_quantity = myForm.stock_quantity.value;

                myForm.method = "post"; //전송방식 post
                myForm.action = "/JSP/update"; //action 속성을 서블릿 매핑 이름으로
                myForm.submit(); //자바스크립트에서 서블릿으로 전송  
                }        

         }
    </script>
</body>
</html>

products.jsp

package common;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class products
 */
public class products extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public products() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //response.getWriter().append("Served at: ").append(request.getContextPath());
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        ResultSet rs = null;
        JDBConnect jdbc = new JDBConnect();
   
    try {
        String sql = "select * from products";
        jdbc.stmt = jdbc.con.createStatement();
        rs = jdbc.stmt.executeQuery(sql);
       
        List<String[]> products = new ArrayList<>();
       
        while (rs.next()) {
            String[] product = new String[6];
           
            product[0] = rs.getString("product_id");
            product[1] = rs.getString("product_name");
            product[2] = rs.getString("category");
            product[3] = rs.getString("price");
            product[4] = rs.getString("description");
            product[5] = rs.getString("stock_quantity");
       
            products.add(product);
        }
   
        request.setAttribute("products", products);
        request.getRequestDispatcher("/2024-09-04/main.jsp").forward(request, response);
   
        }catch (SQLException e){
        out.println("데이터베이스 접속오류:" +e.getMessage());
        } finally {
            try {
                if (rs != null) rs.close();
                if (jdbc.con != null) jdbc.con.close();
            }catch (SQLException e){
                out.println("리소스 해제 오류:" +e.getMessage());
            }  
        }
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

update.java

package common;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.PreparedStatement;
import java.sql.SQLException;

import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
/**
 * Servlet implementation class update1
 */
public class update extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public update() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.getWriter().append("Served at: ").append(request.getContextPath());
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //doGet(request, response);
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();

        String product_id = request.getParameter("product_id");
        String product_name = request.getParameter("product_name");
        String category = request.getParameter("category");
        String price = request.getParameter("price");
        String description = request.getParameter("description");
        String stock_quantity = request.getParameter("stock_quantity");

        JDBConnect jdbc = new JDBConnect();
       
        try {
            String sql = "UPDATE products SET product_name = ?, category = ?, price = ?, description = ?, stock_quantity = ? WHERE product_id = ?";
            try (PreparedStatement pstmt = jdbc.con.prepareStatement(sql)) {
                pstmt.setString(1, product_name);
                pstmt.setString(2, category);
                pstmt.setDouble(3, Double.parseDouble(price));
                pstmt.setString(4, description);
                pstmt.setInt(5, Integer.parseInt(stock_quantity));
                pstmt.setString(6, product_id);

                int rowsUpdated = pstmt.executeUpdate();
                if (rowsUpdated > 0) {
                    out.println("수정완료");
                } else {
                    out.println("실패");
                }
                out.println("<br>");
                out.println("<a href=\"javascript:history.back()\">Go back</a>");
            }
        } catch (NumberFormatException e) {
            out.println("Invalid number format: " + e.getMessage());
        } catch (SQLException e) {
            out.println("Database access error: " + e.getMessage());
        } finally {
            try {
                if (jdbc.con != null) jdbc.con.close();
            } catch (SQLException e) {
                out.println("Error closing resources: " + e.getMessage());
            }
        }
    }
}

update.java

package common;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.PreparedStatement;
import java.sql.SQLException;

import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
/**
 * Servlet implementation class update1
 */
public class update extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public update() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.getWriter().append("Served at: ").append(request.getContextPath());
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //doGet(request, response);
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();

        String product_id = request.getParameter("product_id");
        String product_name = request.getParameter("product_name");
        String category = request.getParameter("category");
        String price = request.getParameter("price");
        String description = request.getParameter("description");
        String stock_quantity = request.getParameter("stock_quantity");

        JDBConnect jdbc = new JDBConnect();
       
        try {
            String sql = "UPDATE products SET product_name = ?, category = ?, price = ?, description = ?, stock_quantity = ? WHERE product_id = ?";
            try (PreparedStatement pstmt = jdbc.con.prepareStatement(sql)) {
                pstmt.setString(1, product_name);
                pstmt.setString(2, category);
                pstmt.setDouble(3, Double.parseDouble(price));
                pstmt.setString(4, description);
                pstmt.setInt(5, Integer.parseInt(stock_quantity));
                pstmt.setString(6, product_id);

                int rowsUpdated = pstmt.executeUpdate();
                if (rowsUpdated > 0) {
                    out.println("수정완료");
                } else {
                    out.println("실패");
                }
                out.println("<br>");
                out.println("<a href=\"javascript:history.back()\">Go back</a>");
            }
        } catch (NumberFormatException e) {
            out.println("Invalid number format: " + e.getMessage());
        } catch (SQLException e) {
            out.println("Database access error: " + e.getMessage());
        } finally {
            try {
                if (jdbc.con != null) jdbc.con.close();
            } catch (SQLException e) {
                out.println("Error closing resources: " + e.getMessage());
            }
        }
    }
}

delete.java

package common;

import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * Servlet implementation class delete
 */
public class delete extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public delete() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //response.getWriter().append("Served at: ").append(request.getContextPath());
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        PreparedStatement pstmt;
        ResultSet rs = null;
        JDBConnect jdbc = new JDBConnect();
       
        try {
            String sql = "delete from products where product_id = ?";
            pstmt = jdbc.con.prepareStatement(sql);
            String delete_id = request.getParameter("delete_id");
            pstmt.setString(1, delete_id);

            int rowsAffected = pstmt.executeUpdate();
            if (rowsAffected > 0) {
                System.out.println(rowsAffected);
                out.println("<script>");
                out.println("alert('상품 삭제 성공');");
                out.println("location.href ='2024-09-04/main.jsp';");
                out.println("</script>");
            }else {
                out.println("<b>상품 삭제 실패</b>");
            }
           
        } catch (SQLException e) {
            out.println("데이터베이스 접속 오류: " + e.getMessage());
        } finally {
            try {
                if (rs != null) rs.close();
                if (jdbc.con != null) jdbc.con.close();
            } catch (SQLException e) {
                out.println("리소스 해제 오류: " + e.getMessage());
            }
        }
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

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