JDBC 실습5 - select(2)

• Role.java(DTO)는 JDBC 실습1 참고

프로젝트 실습

목표 : role 테이블의 모든 데이터를 select로 읽어오기

1. RoleDao.java 코드작성

package kr.or.connect.jdbcexam.dao;

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

import kr.or.connect.jdbcexam.dto.Role;

public class RoleDao {
	private static String dburl = "jdbc:mysql://localhost:3306/connectdb?serverTimezone=UTC";
	private static String dbUser = "connectuser";
	private static String dbpasswd = "PASSWORD";

	public List<Role> getRoles(){
		List<Role> list = new ArrayList<Role>(); 
		
		try {
			Class.forName("com.mysql.cj.jdbc.Driver");
		} catch(ClassNotFoundException e) {
			e.printStackTrace();
		}
		
		String sql = "SELECT description, role_id FROM role order by role_id desc";
		
		// try with resource - finally에서 close를 생략할 수 있는 방법
		try (Connection conn = DriverManager.getConnection(dburl, dbUser, dbpasswd);
				PreparedStatement ps = conn.prepareStatement(sql)){
			
			try(ResultSet rs = ps.executeQuery()){
	
				while (rs.next()) {
					String description = rs.getString(1);
					int id = rs.getInt("role_id");
					Role role = new Role(id, description);
					list.add(role);
				}
			} catch(Exception e) {
				e.printStackTrace();
			}			
		} catch (Exception e) {
			e.printStackTrace();
		}
		return list;
	}
}

2. 실행코드작성

package kr.or.connect.jdbcexam;

import java.util.List;

import kr.or.connect.jdbcexam.dao.RoleDao;
import kr.or.connect.jdbcexam.dto.Role;

public class JDBCExam5 {

	public static void main(String[] args) {
		RoleDao dao = new RoleDao();
		
		List<Role> list = dao.getRoles();
		
		for(Role role : list) {
			System.out.println(role);
		}
	}
}

결과