package jdbc;import java.awt.GradientPaint;import java.sql.*;public class conn { static Connection con; static Statement sql; static ResultSet res; public Connection getConnection(){ try { Class.forName("com.mysql.jdbc.Driver"); Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/db_hotel","root","123456"); System.out.println(conn); } catch (ClassNotFoundException e) { // TODO 自動生成的 catch 塊 e.printStackTrace(); } catch (SQLException e) { // TODO 自動生成的 catch 塊 e.printStackTrace(); } return con; } public static void main(String[] args) { conn c = new conn(); con = c.getConnection(); try { sql = con.createStatement(); ? ? ? ? ? ? ? ? ? ? ? ?//空指針異常 res = sql.executeQuery("select*from tb_room");? ? ? ? ? ??? ? ? ? ? ? while(res.next()){? ? ? ? ? ? String id = res.getString("id");? ? ? ? ? ? String room = res.getString("room");? ? ? ? ? ? String price = res.getString("price");? ? ? ? ? ? String information = res.getString("information");? ? ? ? ? ? System.out.println("id");? ? ? ? ? ? System.out.println("room");? ? ? ? ? ? System.out.println("price");? ? ? ? ? ? System.out.println("information");? ? ? ? ? ? } } catch (SQLException e) { // TODO 自動生成的 catch 塊 e.printStackTrace(); } }}