sql.java

package learn;
import java.sql.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JOptionPane;

public class mySqlConnect{
    
    protected Connection con = null;
    protected Statement stm = null; 
    protected PreparedStatement prstm = null;
    protected CallableStatement cstm = null;
    private final String url = "jdbc:sqlserver://localhost:1433;databaseName=ThuVien;user=sa;password=123456";
    
    public boolean openConnection() throws SQLException{
        if(con.isClosed()){
            try{
            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
            con = java.sql.DriverManager.getConnection(url);
            return true;
            }
        catch (ClassNotFoundException | SQLException e){
            JOptionPane.showMessageDialog(null,"Lỗi kết nối "+e);
          }
        }
        return false;
    }
    
    public boolean closeConnection() throws SQLException{
        if(!con.isClosed()){
            con.close();
            return true;
        }
        return false;
    }
    
    public boolean ExecuteNoneQuery (String sql) throws SQLException{
        if (openConnection()){
            try {
                stm = con.createStatement();
                stm.execute(sql);
            return true;
            } catch (SQLException ex) {
                Logger.getLogger(mySqlConnect.class.getName()).log(Level.SEVERE, null, ex);
            }finally {
                closeConnection();
                stm.close();
            }
        }
        return false;
    }
    
    public ResultSet ExecuteTable(String sql) throws SQLException{
        if(openConnection()){
            try{
             stm = con.createStatement();
             ResultSet rs = stm.executeQuery(sql);
             return rs;
            }catch(Exception ex){
                
            }finally{
                closeConnection();
                stm.close();
            }
        }
        return null;
    }
    
    public static void main(String[] args) {
        mySqlConnect obj = new mySqlConnect();
        try {
            ResultSet rs = obj.ExecuteTable("SELECT maSach from tb_Sach");
            while(rs.next()){
                String tenSach = rs.getString("maSach");
                System.out.println("\n"+tenSach);
            }
        } catch (SQLException ex) {
            Logger.getLogger(mySqlConnect.class.getName()).log(Level.SEVERE, null, ex);
        }
        
    }
}