jdbc my sql 데이터베이스 정보 조회

package com;

import java.io.PrintWriter;
import java.sql.DriverManager;
import java.sql.ResultSet;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.Statement;

import sun.print.resources.serviceui;

public class test {
	public static void main(String[] args) {
		try {
			/*Class.forName("com.mysql.jdbc.Driver");
			
			String conString="jdbc:mysql://localhost:3306/student_db";
			Connection connection=(Connection) DriverManager.getConnection(conString,"root","");
			Statement statement=(Statement) connection.createStatement();
			boolean resultSet=statement.execute("insert into student\r
" + 
					"VALUES(\"201215123\",\"  \",\" \",18,\"cs\");");*/
			/*while (resultSet.next()) {
				System.out.println(resultSet.getString("Sname"));
					
			}*/
			/*connection.close();*/
			 DriverManager.deregisterDriver(new com.mysql.jdbc.Driver());
	            Connection connection=(Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/student_db");
	            PreparedStatement preparedStatement=(PreparedStatement) connection.prepareStatement("select * from student");
	            ResultSet resultSet=preparedStatement.executeQuery();
	            while (resultSet.next()){
	                System.out.println(resultSet.getString("sname"));
	            }
	            resultSet.close();
	            preparedStatement.close();
	            connection.close();
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
}