How to write data into excel sheet using Java

Problem Description

How to write data into excel sheet using Java.

Solution

Following is the program to write data into excel sheet using Java.

import java.io.File;
import java.io.FileOutputStream;

import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

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

      //Create blank workbook
      XSSFWorkbook workbook = new XSSFWorkbook();
      
      //Create a blank sheet
      XSSFSheet spreadsheet = workbook.createSheet( " Employee Info ");

      //Create row object
      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" });
      
      empinfo.put( "2", new Object[] {
         "tp01", "Gopal", "Technical Manager" });
      
      empinfo.put( "3", new Object[] {
         "tp02", "Manisha", "Proof Reader" });
      
      empinfo.put( "4", new Object[] {
         "tp03", "Masthan", "Technical Writer" });
      
      empinfo.put( "5", new Object[] {
         "tp04", "Satish", "Technical Writer" });
      
      empinfo.put( "6", new Object[] {
         "tp05", "Krishna", "Technical Writer" });

      //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);
         }
      }
      //Write the workbook in file system
      FileOutputStream out = new FileOutputStream(
         new File("C:/poiexcel/Writesheet.xlsx"));
      
      workbook.write(out);
      out.close();
      System.out.println("Writesheet.xlsx written successfully");
   }
}

Result