HAshMap to Excel file using APache POI

[sai rama krishna]

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.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
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 POIRIRaw4EEb {
      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="";
            List missingList = new ArrayList();
            
        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;            
  
              
              try{      
                    
                    
                 
                   /* PreparedStatement ps = con.prepareStatement("select null from login where username=? and password=?");
                  //(in the loop)
                  ps.setString(1, username);
                  ps.setString(2, password);
                  ResultSet rs = ps.executeQuery();
                  if(rs.next()) {
                    // Found
                  }*/
                    
                    
                    
                    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+"'");
                    //PreparedStatement psmt=null;
                      PreparedStatement psmt = con.prepareStatement("select null from login where username=? and password=?");
                    psmt.setString(1, username);
                  psmt.setString(2, password);
                  ResultSet rs1 = psmt.executeQuery(); 
                      System.out.println("rs1-->"+rs1);
                              boolean isExist = false;
                              if (rs1!=null) {
                                    while (rs1.next()){
                                            isExist = true;
                                            String rec1 = rs1.getString(1);
                                            String rec2 = rs1.getString(2);
                                            System.out.println("rec1 is--"+rec1+"---rec2 is---"+rec2);
                                    }
                              }
                              
                              if (rs1==null) {
                                  Map mapDetail = new HashMap();
                                  mapDetail.put("username",username);
                                  mapDetail.put("password",password);

	                                int row = 0;
					//Object obj;
					For(Object obj:mapDetail.Keys){
					String value = (String)mapDetail(obj);

					//not sure of this part:
					mySheet.getCells().get(row,0).setValue(value);
					row++;
					}
                                    missingList.add(mapDetail);
                              }


                  //  pstmt.close();
                    con.close();
              }
              catch(Exception e){
                    
                    System.out.println("e-->"+e);
              }
        }
            
            System.out.println("Missing List : "+missingList);
  }
}

I have above program which reads File.xls for username and password info like above. From the missedList hashmap I need to send the username,password information to a excel sheet using apache POI. Please advise on how to send achieve it. Any ideas, suggestions, sample code, links, source code highly appreciated. Thanks in advance

I checked folowing link but does not have what I am looking

http://www.mysamplecode.com/2011/09/generate-large-excel-in-java-using.html

Any ideas, suggestions, sample code, links, source code highly appreciated. Thanks in advance

[K. Tsang]

Hello there

So you are trying:
1) get the username and password from the excel file
2) pass these 2 values to some SQL checking against database if such entry exists
3) if NOT populate this username/password pair into a map and add this map into a list


Also when you loop through your database result set you don't necessarily need to check for null because if there are no records, the rs1.next() will return false and exist the while loop. At this point you will add this so-called missing username/password to your map and list.

Also to simplify your code, why use a list of maps? When you can just use a map since you are working with username/password pairs.

Hope this helps.