너와 나의 연결고리, JSP 🔗(9) - 자바빈즈 태그

joyfulwave·2022년 11월 28일

ACTION TAG Beans Java eclipse jsp 액션태그

웹서버와 연결고리! JSP

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9/12

📚 자바빈즈 태그

📌 자바 빈즈 태그를 사용해보자.

객체생성
java -> MemberBean member = new MemberBean();
jsp -> <jsp:useBean class="전체패키지명.MemberBean" id="member" />

setter()
java -> member.setName("자바학생");
jsp -> <jsp.setProperty name="member" property="name" value="자바학생" />

getter()
java -> member.getName();
jsp -> <jsp.getProperty name="member" property="name" />

⚫ MemberBean.java

  public class MemberBean {
      private String name;
      private int age;
      public String getName() {
          return name;
      }
      public void setName(String name) {
          this.name = name;
      }
      public int getAge() {
          return age;
      }
      public void setAge(int age) {
          this.age = age;
      }

  }

⚫ DBConnction.java

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

  public class DBConnection {
      public static Connection getConnection() {
          Connection conn = null;

          try {
              String driver = "oracle.jdbc.driver.OracleDriver";
              String url = "jdbc:oracle:thin:@localhost:1521:xe";
              String user = "이름";
              String password = "비밀번호";			

              Class.forName(driver);
              conn = DriverManager.getConnection(url, user, password);
          } catch (ClassNotFoundException e) {
              e.printStackTrace();
              System.out.println("드라이버 로딩 실패");
          } catch (SQLException e) {
              e.printStackTrace();
              System.out.println("DB 접속 오류");
          } catch(Exception e) {
              e.printStackTrace();
              System.out.println("알 수 없는 오류");
          }

          return conn;
      }
  }

⚫ MemberDAO.java

  import java.sql.Connection;
  import java.sql.PreparedStatement;
  import java.sql.ResultSet;
  import java.sql.SQLException;
  import java.util.ArrayList;

  import com.koreait.web.beans.MemberBean;

  public class MemberDAO {

      //	db 접근에 관한 비즈니스 로직	
      Connection conn;
      PreparedStatement pstm;
      ResultSet rs;

      public int getAge(String name) {

          String sql = "SELECT AGE FROM MEMBER WHERE name = ?";
          int age = 0;

          try {
              conn = DBConnection.getConnection();		
              pstm = conn.prepareStatement(sql);
              pstm.setString(1, name);
              rs = pstm.executeQuery();

              if( rs.next() ) {
                  age = rs.getInt(1);
              }

          } catch (SQLException e) {
              e.printStackTrace();
              System.out.println("DB 접속 오류");
          }	catch(Exception e) {
              e.printStackTrace();
              System.out.println("알 수 없는 오류");
          }
          return age;
      }

      public ArrayList<MemberBean> selectAll() {

          String sql = "SELECT * FROM MEMBER";

          ArrayList<MemberBean> result = new ArrayList<>();

          try {
              conn = DBConnection.getConnection();		
              pstm = conn.prepareStatement(sql);			
              rs = pstm.executeQuery();

              while(rs.next()) {
                  MemberBean member = new MemberBean();
                  member.setName(rs.getString(1));
                  member.setAge(rs.getInt(2));

                  result.add(member);
              }

          } catch (SQLException e) {
              e.printStackTrace();
              System.out.println("DB 접속 오류");
          }	catch(Exception e) {
              e.printStackTrace();
              System.out.println("알 수 없는 오류");
          }

          return result;
      }
  }

⚫ bean_test.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>
      <!-- 자바빈즈 태그 -->

      <!-- MemberBean 클래스로 객체 생성 -->
      <jsp:useBean class="com.koreait.web.beans.MemberBean" id="member" />

      <!-- setter() -->
      <jsp:setProperty property="name" name="member" value="김자바"/>
      <jsp:setProperty property="age" name="member" value="20"/>

      <!-- getter() -->
      <table border="1">
          <tr>
              <th>이름</th>
              <th>나이</th>
          </tr>
          <tr>
              <td><jsp:getProperty property="name" name="member"/></td>
              <td><jsp:getProperty property="age" name="member"/></td>
          </tr>		
      </table>

  </body>
  </html>