How to add new sheets to existing excel workbook using apache POI?

Question

I am trying to write List data into multiple excel sheet in one work book. like for first list, the code will create new workbook and create new sheet for list[1], for secon

Answer 1

While working with existing workbook , You should not create a file object , Just need to Provide the File Location to FileInputStream object and pass it's reference to workbook object, then do whatever you want to do with the existing file. To add a sheet just use create Method command

public void AddsheetintoExistingworkbook(String sheetname) throws IOException, InvalidFormatException{

    //***************************Add a sheet into Existing workbook***********************************************


 String path="C:\\Workspace\\Selenium_2.53\\src\\InputFiles\\Temp.xlsx";
 fileinp = new FileInputStream(path);
 workbook = new XSSFWorkbook(fileinp);
 workbook.createSheet(sheetname);

 fileOut = new FileOutputStream(path);
    workbook.write(fileOut);
    fileOut.close();
 System.out.println("File is written successfully");    
}

Answer 2

To add more than one Excel sheet to a new Excel file, those sheets need to be created from one workbook, and written once to the file output stream

import java.io.*;
import java.util.*;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.*;

public class JustATest {
   public static void main(String[] args) throws Exception  {       

        XSSFWorkbook AWorkbook = new XSSFWorkbook(); //Create blank workbook 

        for (int i = 0; i < 10; i++) {
            XSSFSheet spreadsheet = AWorkbook.createSheet(" Employee "+i);

            // the follwing code is to create dummy data in sheets 
            // is similar to the one at tutorialPoint.com
            XSSFRow row;            
            //This data needs to be written (Object[])
            Map < String, Object[] > empinfo =    new TreeMap< String, Object[] >();
            empinfo.put( "1", new Object[] { "EMP ID", "EMP NAME", "DESIGNATION" });
            for (int j = 0; j < i; j++) {
                empinfo.put( j+2+"", new Object[] {  j+2+"", "Fadel K", "Technical Manager" });                
            }          
            //Iterate over data and write to sheet
            Set<String> keyid = empinfo.keySet();
            int rowid = 0;
            for (String key : keyid){
               row = spreadsheet.createRow(rowid++);
               Object [] objectArr = empinfo.get(key);
               int cellid = 0;
               for (Object obj : objectArr){
                  Cell cell = row.createCell(cellid++);
                  cell.setCellValue((String)obj);
               }
            }            
            // dummy data creation over.
        }       

        // here you write all sheets at once, by writing the entier workbook
        FileOutputStream out = new FileOutputStream(new File("AllData.xlsx"));
        AWorkbook.write(out);
        out.close();               
   }
}

Answer 3

If file does not exist then this code creates new file and also creates sample sheet1 but if file exists then it adds new sheet to existing excel file.

    HSSFWorkbook workbook = null;
    File file = new File(context.getExternalFilesDir(null), "Sample.xls");
    FileOutputStream fileOut = new FileOutputStream(file);

    if (file.exists()) {
        try {
            workbook = (HSSFWorkbook)WorkbookFactory.create(file);
        } catch (InvalidFormatException e) {
            e.printStackTrace();
        }
        HSSFSheet sheet = workbook.createSheet("Sample sheet2");
    }
    else{
        workbook = new HSSFWorkbook();
        HSSFSheet sheet = workbook.createSheet("Sample sheet1");
    }
    workbook.write(fileOut);
    fileOut.close();

Answer 4

You can use Bhaskar's code to work things out and to use WorkbookFactory you will probably need to donwload poi-ooxml-3.7.jar file.

Here is the link for you:

http://grepcode.com/snapshot/repo1.maven.org/maven2/org.apache.poi/poi-ooxml/3.7

Answer 5

Looks like you are only writing out the sheet not the workbook