Create Excel :- Header/color/columns etc...

package Excel_create_style;

import org.apache.poi.*;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.VerticalAlignment;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.apache.poi.ss.usermodel.BorderStyle;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.FillPatternType;
import org.apache.poi.ss.usermodel.Font;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.apache.poi.ss.usermodel.IndexedColors;
import org.apache.poi.ss.usermodel.PatternFormatting;

import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

public class Test2 {

public static void main(String[] args)
{
  //Workbook workbook = new XSSFWorkbook();
  Workbook workbook = new HSSFWorkbook();  
  Sheet sheet1 = workbook.createSheet("sheet1");
  Sheet sheet2 = workbook.createSheet("sheet 2");
  HSSFRow row;
 
  Row header = (HSSFRow) sheet1.createRow(0);
  sheet1.addMergedRegion(new CellRangeAddress(0,0,1,7)); //--Merge
  header.createCell(1).setCellValue("Output Structure"); //
  //Heder style
  Font font_h = workbook.createFont();
  font_h.setBold(true);
  font_h.setFontHeightInPoints((short)12);
  CellStyle Styleheader = workbook.createCellStyle();
  Styleheader.setAlignment(HorizontalAlignment.CENTER);  
  Styleheader.setFont(font_h);
  Styleheader.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.getIndex());
  Styleheader.setFillPattern(FillPatternType.SOLID_FOREGROUND);
 
  header.getCell(1).setCellStyle(Styleheader);
 
  //************************************
 
     
  //************************************
 
  //--- Row 2 me ye headers aaega
  row = (HSSFRow) sheet1.createRow(2);
  row.setHeight((short) 500);

  row.createCell(1).setCellValue("Segment");
  row.createCell(2).setCellValue("Region");
  row.createCell(3).setCellValue("Borrower Name");
  row.createCell(4).setCellValue("RM Name");
  row.createCell(5).setCellValue("Date Full Information received");
  row.createCell(6).setCellValue("Date Letter Issued");
  row.createCell(7).setCellValue("Date RM Letter Requested");
 
 
  //---
  //----Font Formatting
 
  for(int i =1;i<=7;i++) {
  CellStyle stylerowHeading = workbook.createCellStyle();
  Font font = workbook.createFont();
  font.setBold(true);
  font.setFontHeightInPoints((short)10);
  stylerowHeading.setFont(font);
  stylerowHeading.setAlignment(HorizontalAlignment.CENTER);
  stylerowHeading.setVerticalAlignment(VerticalAlignment.CENTER);
  stylerowHeading.setFillForegroundColor(IndexedColors.TURQUOISE.getIndex());
  stylerowHeading.setFillPattern(FillPatternType.SOLID_FOREGROUND);
 
  stylerowHeading.setBorderLeft(BorderStyle.MEDIUM);
  stylerowHeading.setBorderRight(BorderStyle.MEDIUM);
  stylerowHeading.setBorderTop(BorderStyle.MEDIUM);
  stylerowHeading.setBorderBottom(BorderStyle.MEDIUM);
 
  row.getCell(i).setCellStyle(stylerowHeading);
  }
 
  //------Auto Fit
  for(int i =1;i<=7;i++)
  {
  sheet1.autoSizeColumn(i);
  }
 
 
  //*****************
  //CellStyle dynamic_rows = workbook.createCellStyle();
  //dynamic_rows.setBorderLeft(BorderStyle.THIN);
  //dynamic_rows.setBorderRight(BorderStyle.THIN);
  //dynamic_rows.setBorderBottom(BorderStyle.THIN);
 
  //******************
 
  String[] rowVal = new String[7];
  insertrowVal(rowVal);  
  Map < String, String[]> m = new LinkedHashMap < String, String[] >();
  //m.put( "1", rowVal);
  m.put( "1", rowVal);
  m.put( "2", rowVal);
  m.put( "3", rowVal);
  m.put( "4", rowVal);
  m.put( "5", rowVal);
   
//Iterate over data and write to sheet
      Set <String> keyid = m.keySet();
      int rowid = 3;

      for (String key : keyid) {
    row = (HSSFRow) sheet1.createRow(rowid++);
         String [] str = m.get(key);
         int cellid = 1;
     
         for (String obj : str)
         {
        //row.getCell(cellid).setCellStyle(dynamic_rows);
            Cell cell = row.createCell(cellid++);
            cell.setCellValue((String)obj);
           
         }
      }
     
  try
  {
  FileOutputStream output = new FileOutputStream("D:\\work\\newgen2.xls");
  workbook.write(output);
  output.close();
  System.out.println("File created ....");

  }
  catch(Exception e)
  {
  e.printStackTrace();
  }
 
 
}

private static void insertrowVal(String[] rowVal)
{
rowVal[0]="apple";
rowVal[1]="Orange";
rowVal[2]="Banana";
rowVal[3]="Mango";
rowVal[4]="Papaya";
rowVal[5]="Lichy";
rowVal[6]="Grapes";

}

}

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JARS :- poi-bin-4.1.0-20190412.tar