Database Connection - OracleTest.java

1. DBConnection.java

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
 
public class DBConnection 
{
    public static Connection dbConn;
    
    public static Connection getConnection()
    {
      Connection conn = null;
      try {
        String user = "scott"; 
        String pw = "tiger";
        String url = "jdbc:oracle:thin:@localhost:1521:orcl";

        Class.forName("oracle.jdbc.driver.OracleDriver");        
        conn = DriverManager.getConnection(url, user, pw);

        System.out.println("Database에 연결되었습니다.\n");

      } catch (ClassNotFoundException cnfe) {
          System.out.println("DB 드라이버 로딩 실패 :"+cnfe.toString());
      } catch (SQLException sqle) {
          System.out.println("DB 접속실패 : "+sqle.toString());
      } catch (Exception e) {
          System.out.println("Unkonwn error");
          e.printStackTrace();
      }
    return conn;     
    }
}

 

2. DB 데이터추출 구현부

package DB;

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

public class OracleTest
{
    public static void main(String args[])
    {
        Connection conn = null; // DB연결된 상태(세션)을 담은 객체
        PreparedStatement pstm = null; // SQL 문을 나타내는 객체
        ResultSet rs = null; // 쿼리문을 날린것에 대한 반환값을 담을 객체
        
        try {
          // SQL 문장을 만들고 만약 문장이 질의어(SELECT문)라면
          // 그 결과를 담을 ResulSet 객체를 준비한 후 실행시킨다.
          String quary = "SELECT * FROM (select * from TEMP order by empno) where rownum<=10";
          //String quary = "SELECT * FROM (select * from TEMP order by EMP_#) fetch first 100 rows only";
          conn = DBConnection.getConnection();
          pstm = conn.prepareStatement(quary);
          rs = pstm.executeQuery();
          System.out.println("EMPNO EMP_X KoreanName HanmunName CommonNumber");
          System.out.println("============================================");

          while(rs.next()){
              String empno = rs.getString(1);
              int emp_x = rs.getInt(2);
              String Korean_name = rs.getString(3);
              String Han_name = rs.getString(4);
              int comm = rs.getInt("RES_#1");
              //java.sql.Date hiredate = rs.getDate(5); // Date 타입 처리
              String result = empno+" "+emp_x+" "+Korean_name+" "+Han_name+" "+comm;
              //                      직원번호       구분           한글이름             한문이름        주민번호
              System.out.println(result);
           }
           
        } catch (SQLException sqle) {
        	System.out.println("SELECT문에서 예외 발생");
        	sqle.printStackTrace();
            
        }finally{
        // DB 연결을 종료한다.
            try{
                if ( rs != null ){rs.close();}
                if ( pstm != null ){pstm.close();}
                if ( conn != null ){conn.close(); }
                
            }catch(Exception e){
            	throw new RuntimeException(e.getMessage());
            }
        }
    }
}