JDBC 사용 예제

package JDBC_Oracle;

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

// 데이터 조회 프로그램
public class Oracle_SelectSample {
	// 프로그램 전체 공유, 클래스 변수
	private static int no; 
	private static String name;
	private static String email;
	private static String tel;

	public static void main(String[] args) {
	// 1. 드라이버 로딩
		String driver = "oracle.jdbc.driver.OracleDriver";
		String url = "jdbc:oracle:thin:@localhost:1521:xe";
		String id = "java";
		String password = "1234";		
		
	// 2. Connection
		try {
			Class.forName(driver);
		} catch (ClassNotFoundException e1) {
			e1.printStackTrace();
		}
		
		Connection conn = null;
		try {
			conn = DriverManager.getConnection(url, id, password);
		} catch (SQLException e1) {
			System.out.println("DB 접속이 실패했습니다. URL : " + url + "\tID : " + id + "\tPW : " + password);
			e1.printStackTrace();
		}
		
	// 3. SQL 실행
		String sql = "select * from member";
		PreparedStatement pstmt = null;
		try {
			pstmt = conn.prepareStatement(sql);
		} catch (SQLException e1) {
			e1.printStackTrace();
		}
		
		ResultSet rs = null;
		try {
			rs = pstmt.executeQuery();
		} catch (SQLException e1) {
			e1.printStackTrace();
		}
		
	// 4. 조회, 삭제, 수정, 입력
		System.out.println("--------------------------------------------------------");
		System.out.println("번호 \t 이름 \t 이메일 \t 전화번호");
		System.out.println("--------------------------------------------------------");
		
		try {
			while(rs.next()) {
				no = rs.getInt("no");
				name = rs.getString("name");
				email = rs.getString("email");
				tel = rs.getString("tel");
				System.out.println(no + "\t" + name + "\t" + email + "\t" + tel);
			}
		} catch (SQLException e1) {
			e1.printStackTrace();
		}
		
		System.out.println("--------------------------------------------------------");
			
	// 5. Connection 해제
	// Connection 연결과 반대로 진행
		try {
			if(rs != null) {
				rs.close();
			}
			if(pstmt != null) {
				pstmt.close();
			}
			if(conn != null) {
				conn.close();
			}
		} catch(Exception e) {
			System.out.println("Unknown error happens");			
		}
	}
}