(JAVA / JDBC) JDBC로 JAVA와 DB 연결하기 - Oracle

- 간단한 실습을 겸한 oracle 연동 코드

package day22;
 
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Scanner;
 
class Student{
    int snum;
    String sname;
    
    Student(int snum, String sname){
        this.snum = snum;
        this.sname = sname;
    }
 
    @Override
    public String toString() {
        return "학생정보 [번호=" + snum + ", 이름=" + sname + "]";
    }
        
}
public class Test2 {
 
   public static void main(String[] args) {
      String DName="oracle.jdbc.driver.OracleDriver";
 
      String url="jdbc:oracle:thin:@localhost:1521:xe";
      String user="oh";
      String password="0000";
 
      Connection conn=null;
      Statement stmt=null;
      
      Scanner sc = new Scanner(System.in);
      
      ArrayList<Student> data = new ArrayList();
 
      try {
         Class.forName(DName);
 
         conn=DriverManager.getConnection(url, user, password);
 
         stmt=conn.createStatement();
         
         // 1번 출력
         ResultSet rs=stmt.executeQuery("select * from student");
         while(rs.next()) {
            int snum = rs.getInt("snum");
            String sname = rs.getString("sname");
            data.add(new Student(snum, sname));
         }
         
         for(Student v : data) {
             System.out.println(v);
         }
         rs.close();
         
         // 2번 수정
         System.out.println("===== 이름 수정 =====");
         
         for(Student v : data) {
             System.out.println(v.sname + "의 이름을 무엇으로 수정하시겠습니까?");
             System.out.print("입력: ");
             String sname = sc.next();
             String sql = "UPDATE student SET sname = '" + sname +"' WHERE snum = " + v.snum;
             stmt.executeUpdate(sql);
         }
         
         System.out.println("이름에 김이 들어간 녀석을 찾아볼까?");
         rs=stmt.executeQuery("select sname from student where sname LIKE '%김%'");
         
         while(rs.next()) {
             System.out.print(rs.getString("sname") + " ");
         }
         rs.close();
         
         
      }catch(Exception e) {
         System.out.println("예외발생!");
      }finally {
         try {
            stmt.close();
            conn.close();
         } catch (SQLException e) {
            e.printStackTrace();
         }
      }
   }
 
}