สอบถามการคอนเนค mysql ตอนส่งค่าไปที่ Doget หน่อยครับ JAVA

package com;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;






public class Dbconnection {
	static Connection conn = null;
	
	
		
	public static Connection ConnectDb() {
		
	    String classforname = "com.mysql.jdbc.Driver";
	    String url = "jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8";	    
	    String user = "root";
	    String password = "1234";
		
	    try
		{
		Class.forName(classforname);
		 conn = DriverManager.getConnection(url, user, password);		
		return conn;
		}
		catch (ClassNotFoundException | SQLException e)
		{
		 System.out.println("Cannot Connection Database");
		return null;
		}
		}
	}



	

package com;

import com.Dbconnection;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;





@WebServlet("/servlet")
public class Servlet extends HttpServlet {
	 
	
	 
	private static final long serialVersionUID = 1L;
       
  
    public Servlet() {
        super();
        
        
    }


    
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		 		
		
		
	}
	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		 
		String n = request.getParameter("name");
		 System.out.println(n);	  	
		
		 
        String sql = "select * from books WHERE isbn = "+n;
        System.out.println(sql);
        
        
        
    		try{
    		//Connection conn = null;
    	    //Connection conn = Dbconnection.ConnectDb();
    	    //Statement st = null;
    	    //ResultSet rs = null;
    			
    	 Statement st = Dbconnection.ConnectDb().createStatement();
    	 ResultSet rs = st.executeQuery(sql);
	      
	       
        while((rs!=null) && (rs.next())) {
       	 String isbn = (rs.getString("ISBN")+" ");
       	 String title =(rs.getString("TITLE")+" ");
       	 String author =(rs.getString("AUTHOR")+" ");
       	 String price =(rs.getInt("PRICE")+" ");	
       	 
       	 System.out.println(isbn);
       	 System.out.println(title);
       	 System.out.println(author);
       	 System.out.println(price);
       	 
			}
    		} 
	        catch(Exception e){	          
	            System.out.println("Cannot Connect Database");
	        }
		
    		request.getRequestDispatcher("Index.jsp").forward(request, response);
		
	}
	}

package com;


import java.sql.ResultSet;
import java.sql.Statement;
import com.Dbconnection;

public class test {
	public static void main(String[] args) {
	  //Connection conn = null;
	  //conn = Dbconnection.ConnectDb();
	  //Statement st = null;
	  //ResultSet rs = null;
	  
	  String sql = "select * from books WHERE isbn = 123";
      
      try{
    	  Statement st = Dbconnection.ConnectDb().createStatement();
	      ResultSet rs = st.executeQuery(sql);
     
      
   while((rs!=null) && (rs.next())) {
  	 String isbn = (rs.getString("ISBN")+" ");
  	 String title =(rs.getString("TITLE")+" ");
  	 String author =(rs.getString("AUTHOR")+" ");
  	 String price =(rs.getInt("PRICE")+" ");	
  	 
  	 System.out.print(isbn);
  	 System.out.print(title);
  	 System.out.print(author);
  	 System.out.print(price);
		}
		} 
      catch(Exception e){	          
          
      }    
}

}