Java การสร้างตัวแปรจัดเก็บข้อมูลจากฐานข้อมูลโดยใช้จาวา และแสดงออกนอกคำสั่งwhile

package db;

import java.sql.*;
import javax.sql.*;

public class ConnectMySQL{
String dbUrl, username,password;
Connection con = null;
public ConnectMySQL(String url, String dbName, String usr, String pwd){
   String dbtime;
   dbUrl = "jdbc:mysql://"+url+"/"+dbName;//your.database.domain/yourDBname";
   String dbClass = "com.mysql.jdbc.Driver";
   String query = "Select * FROM users";
   username = usr;
   password = pwd;
   try {

     Class.forName("com.mysql.jdbc.Driver");
     con = DriverManager.getConnection (dbUrl,usr,pwd);
     
   } //end try

   catch(ClassNotFoundException e) {
      e.printStackTrace();
   }
   catch(SQLException e) {
      e.printStackTrace();
   }   
}

public void closeDB(){
   try {
   if(con != null)
      con.close();
   } //end try
   catch(SQLException e) {
      e.printStackTrace();
   }    
}// end closeDB
public ResultSet select(String sqlCode){
    ResultSet rs = null;
    try{
       if(con != null){
          Statement st = con.createStatement();
          rs = st.executeQuery(sqlCode);
       }
    }catch(SQLException e) {
      e.printStackTrace();
   }
   return rs;
}
public boolean insert (String command)throws SQLException{
           if(con != null){
          Statement st = con.createStatement();
          st.executeUpdate(command);
          return true;
           }else return false;
}

public boolean update (String command)throws SQLException{
           if(con != null){
          Statement st = con.createStatement();
          st.executeUpdate(command);
          return true;
           }else return false;
}

public boolean delete (String command)throws SQLException{
           if(con != null){
          Statement st = con.createStatement();
          st.executeUpdate(command);
          return true;
           }else return false;
}

public static void main(String args[]){
String dbtime;
String dbUrl = "jdbc:mysql://your.database.domain/yourDBname";
String dbClass = "com.mysql.jdbc.Driver";
String query = "Select * FROM users";

try {
    //################################## Start distinct  #################################################
//// คำสัง connect    
ConnectMySQL mysql = new ConnectMySQL("localhost","pnotebook","root","1111");
String cmd = "select weight_cpu,cputype_bit,cpu_speed from dcpu";    //คำสั่ง SQL
ResultSet dcpu = mysql.select(cmd);

while(dcpu.next()){                                     // ส่วนของการแสดง
    String weight_cpu=dcpu.getString("weight_cpu");
    String cputype_bit=dcpu.getString("cputype_bit");
    String cpu_speed=dcpu.getString("cpu_speed");
    System.out.println(weight_cpu+"  "+cputype_bit+"  "+cpu_speed);
}

System.out.println("///////////////");
String cmd2 = "select * from dram";    //คำสั่ง SQL
ResultSet dram = mysql.select(cmd2);

while(dram.next()){                                     // ส่วนของการแสดง
    String weight_ram=dram.getString("weight_ram");
    String ramtype_bit=dram.getString("ramtype_bit");
    String ram_speed=dram.getString("ram_speed");
    System.out.println(weight_ram+"  "+ramtype_bit+"  "+ram_speed);
}

System.out.println("///////////////");
String cmd3 = "select * from dvga";    //คำสั่ง SQL
ResultSet dvga = mysql.select(cmd3);

while(dvga.next()){                                     // ส่วนของการแสดง
    String weight_vga=dvga.getString("weight_vga");
    String vgatype_bit=dvga.getString("vgatype_bit");
    String vga_speed=dvga.getString("vga_speed");
    System.out.println(weight_vga+"  "+vgatype_bit+"  "+vga_speed);
}

System.out.println("///////////////");
String cmd4 = "select * from dweight";    //คำสั่ง SQL
ResultSet dweight = mysql.select(cmd4);

while(dweight.next()){                                     // ส่วนของการแสดง
    String weight_product=dweight.getString("weight_product");
    
    System.out.println(weight_product);
}


//################################## End distinct  #################################################


//################################## Start number distinct  #################################################
System.out.println("///////////////");
String cmd5 = "select * from cdcpu";    //คำสั่ง SQL
ResultSet ccpu = mysql.select(cmd5);

while(ccpu.next()){                                     // ส่วนของการแสดง
    String cdcpu=ccpu.getString("ccpu");
    
    System.out.println(cdcpu);
}


String cmd6 = "select * from cdram";    //คำสั่ง SQL
ResultSet cram = mysql.select(cmd6);

while(cram.next()){                                     // ส่วนของการแสดง
    String cdram=cram.getString("cram");
    
    System.out.println(cdram);
}


String cmd7 = "select * from cdvga";    //คำสั่ง SQL
ResultSet cvga = mysql.select(cmd7);

while(cvga.next()){                                     // ส่วนของการแสดง
    String cdvga=cvga.getString("cvga");
    
    System.out.println(cdvga);
}


String cmd8 = "select * from cdweight";    //คำสั่ง SQL
ResultSet cweight = mysql.select(cmd8);

while(cweight.next()){                                     // ส่วนของการแสดง
    String cdweight=cweight.getString("cweight");
}
    


//################################## End number distinct  #################################################


String cmd9 = "select * from productbit";    //คำสั่ง SQL
ResultSet product = mysql.select(cmd9);

while(product.next()){                                     // ส่วนของการแสดง
    String productid=product.getString("productid");
    String cpu_bit=product.getString("cpu_bit");
    String cputype_bit=product.getString("cputype_bit");
    String cpu_speed=product.getString("cpu_speed");
    String ram_bit=product.getString("ram_bit");
    String ramtype_bit=product.getString("ramtype_bit");
    String ram_speed=product.getString("ram_speed");
    String vga_bit=product.getString("vga_bit");
    String vgatype_bit=product.getString("vgatype_bit");
    String vga_speed=product.getString("vga_speed");
    String weight_bit=product.getString("weight_bit");
    System.out.println(productid+"  "+cpu_bit+"  "+cputype_bit+"  "
            +cpu_speed+"  "+ram_bit+"  "+ramtype_bit+"  "+ram_speed+"  "
            +vga_bit+"  "+vgatype_bit+"  "+vga_speed+"  "+weight_bit);
}




mysql.closeDB();     // ปิดฐานข้อมูล

}catch(Exception e) {
e.printStackTrace();
}

}  //end main

}  //end class