How to apply bold text style for an entire row using Apache POI?

How to make an entire excel row cells bold text using Apache POI?

E.g:
Column headings should be in bold. Instead of applying style for each and every cell of heading row, how can I apply some style to an entire row?

This should work fine.

    Workbook wb = new XSSFWorkbook("myWorkbook.xlsx");
    Row row=sheet.getRow(0);
	CellStyle style=null;
	
	XSSFFont defaultFont= wb.createFont();
	defaultFont.setFontHeightInPoints((short)10);
	defaultFont.setFontName("Arial");
	defaultFont.setColor(IndexedColors.BLACK.getIndex());
	defaultFont.setBold(false);
	defaultFont.setItalic(false);
	
	XSSFFont font= wb.createFont();
	font.setFontHeightInPoints((short)10);
	font.setFontName("Arial");
	font.setColor(IndexedColors.WHITE.getIndex());
	font.setBold(true);
	font.setItalic(false);
	
	style=row.getRowStyle();
	style.setFillBackgroundColor(IndexedColors.DARK_BLUE.getIndex());
    style.setFillPattern(CellStyle.SOLID_FOREGROUND);
	style.setAlignment(CellStyle.ALIGN_CENTER);
	style.setFont(font);
	

If you do not create defaultFont all your workbook will be using the other one as default.

Please find below the easy way :

XSSFCellStyle style = workbook.createCellStyle();
style.setBorderTop((short) 6); // double lines border
style.setBorderBottom((short) 1); // single line border
XSSFFont font = workbook.createFont();
font.setFontHeightInPoints((short) 15);
font.setBoldweight(XSSFFont.BOLDWEIGHT_BOLD);
style.setFont(font);                 

Row row = sheet.createRow(0);   
Cell cell0 = row.createCell(0);
cell0.setCellValue("Nav Value");
cell0.setCellStyle(style);  
for(int j = 0; j<=3; j++)
row.getCell(j).setCellStyle(style);

This work for me

I set style's font before and make rowheader normally then i set in loop for the style with font bolded on each cell of rowhead. Et voilà first row is bolded.

HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("FirstSheet");
HSSFRow rowhead = sheet.createRow(0); 
HSSFCellStyle style = wb.createCellStyle();
HSSFFont font = wb.createFont();
font.setFontName(HSSFFont.FONT_ARIAL);
font.setFontHeightInPoints((short)10);
font.setBold(true);
style.setFont(font);
rowhead.createCell(0).setCellValue("ID");
rowhead.createCell(1).setCellValue("First");
rowhead.createCell(2).setCellValue("Second");
rowhead.createCell(3).setCellValue("Third");
for(int j = 0; j<=3; j++)
rowhead.getCell(j).setCellStyle(style);

This worked for me

	Object[][] bookData = { { "col1", "col2", 3 }, { "col1", "col2", 3 }, { "col1", "col2", 3 },
			{ "col1", "col2", 3 }, { "col1", "col2", 3 }, { "col1", "col2", 3 } };

	String[] headers = new String[] { "HEader 1", "HEader 2", "HEader 3" };
	
	int noOfColumns = headers.length;
	int rowCount = 0;

	Row rowZero = sheet.createRow(rowCount++);
	CellStyle style = workbook.createCellStyle();
	Font font = workbook.createFont();
	font.setBoldweight(Font.BOLDWEIGHT_BOLD);
	style.setFont(font);
	for (int col = 1; col <= noOfColumns; col++) {
		Cell cell = rowZero.createCell(col);
		cell.setCellValue(headers[col - 1]);
		cell.setCellStyle(style);
	}

A worked, completed and simple example:

package io.github.baijifeilong.excel;

import lombok.SneakyThrows;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.FileOutputStream;

/**
 * Created by [email protected] at 2019/12/6 11:41
 */
public class ExcelBoldTextDemo {

    @SneakyThrows
    public static void main(String[] args) {

        new XSSFWorkbook() {{
            XSSFRow row = createSheet().createRow(0);
            row.setRowStyle(createCellStyle());
            row.getRowStyle().getFont().setBold(true);
            row.createCell(0).setCellValue("Alpha");
            row.createCell(1).setCellValue("Beta");
            row.createCell(2).setCellValue("Gamma");
        }}.write(new FileOutputStream("demo.xlsx"));
    }
}