PrepareStatement to build query on MYSQL server

Hi,

I would like to use PrepareStatement to build my query by supplying the parameters based on spreadsheet data on mysql database. How can i achieve it.


I wrote my application like

import java.io.FileInputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Iterator;
import java.util.Vector;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;

public class POIRIRaw4EE {
      public static void main( String [] args ) {
            String fileName="C:\\File.xls";
            Vector dataHolder=read(fileName);
            checkDatabase(dataHolder);
      }
      public static Vector read(String fileName)    {
            Vector cellVectorHolder = new Vector();
            try{
                  FileInputStream myInput = new FileInputStream(fileName);
                  POIFSFileSystem myFileSystem = new POIFSFileSystem(myInput);
                  HSSFWorkbook myWorkBook = new HSSFWorkbook(myFileSystem);
                  HSSFSheet mySheet = myWorkBook.getSheetAt(0);
                  Iterator rowIter = mySheet.rowIterator();
                  while(rowIter.hasNext()){
                        HSSFRow myRow = (HSSFRow) rowIter.next();
                        Iterator cellIter = myRow.cellIterator();
                        Vector cellStoreVector=new Vector();
                        while(cellIter.hasNext()){
                              HSSFCell myCell = (HSSFCell) cellIter.next();
                              cellStoreVector.addElement(myCell);
                        }
                        cellVectorHolder.addElement(cellStoreVector);
                  }
            }catch (Exception e){e.printStackTrace(); }
            return cellVectorHolder;
      }
      private static void checkDatabase(Vector dataHolder) {
            String username="";
            String password="";
            PreparedStatement pstmt = null;      
            for (int i=1;i<dataHolder.size(); i++){
                  Vector cellStoreVector=(Vector)dataHolder.elementAt(i);
                  HSSFCell myCell = (HSSFCell)cellStoreVector.elementAt(0);
                  String stringCellValue = myCell.toString();
                  username = stringCellValue;
                  
                  myCell = (HSSFCell)cellStoreVector.elementAt(1);
                  stringCellValue = myCell.toString();
                  password=stringCellValue;
                  
                  //System.out.println("value username--->"+username);
                  //System.out.println("value password-->"+password);
                  
                  try{
                        Class.forName("com.mysql.jdbc.Driver").newInstance();
                        Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root", "root");
                        Statement stmt = con.createStatement();
                        ResultSet rs1 = stmt.executeQuery("select * from login where username='"+username+"' and password='"+password+"'");
                        System.out.println("rs1-->"+rs1);
                        while (rs1.next()){
                              String rec1 = rs1.getString(1);
                              String rec2 = rs1.getString(2);
                              System.out.println("rec1 is--"+rec1+"---rec2 is---"+rec2);
                        }


                        pstmt.close();
                        con.close();
                  }
                  catch(Exception e){
                        
                        System.out.println("e-->"+e);
                  }
            }
      }
}

I am getting console output like

rs1-->com.mysql.jdbc.JDBC4ResultSet@1006d75
rec1 is--jim---rec2 is---yyy
e-->java.lang.NullPointerException
rs1-->com.mysql.jdbc.JDBC4ResultSet@1ccce3c
rec1 is--bill---rec2 is---zzz
e-->java.lang.NullPointerException



since those excel(File.xls) records are already there in login table as well. Now I would like to I would like extend program to use PrepareStatement to build my query by supplying the parameters based on spreadsheet data.

Any ideas, suggestions, sample code, links, source code highly appreciated. Thanks in advance
LoginTable.JPG
File.xls