Excel headers uneditable poi - excel

Question

I want to make the header row of my excel uneditable using poi.
I got various solutions around the internet which say to firstly do sheet.protectSheet("password") which ultimately makes entire sheet uneditable and then loop through all cells which can be editable and set cellStyle for them as cellStyle.setLocked(false).
In my case since the excel just contains headers and rest of the rows will be filled up by the user I can't make the entire sheet uneditable, I just want the headers to be uneditable by the user. How can I achieve this?

Answer 1

Using XSSF the following could be achieved:
Set a CellStyle having setLocked false as the default style for all columns. This is possible by setting a org.openxmlformats.schemas.spreadsheetml.x2006.main.CTCol element having min col 1 and max col 16384 having set that style.
Then take out row 1 from using that style by setting CustomFormat true for that row. So it does not use the default style for all columns. Additional set a CellStyle having setLocked true as the default style for that row. This is possible by getting a org.openxmlformats.schemas.spreadsheetml.x2006.main.CTRow element from that row and set CustomFormat and S(style) there.
Result: All cells are unlocked except row 1.
Example:
import java.io.*;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.*;
public class CreateExcelSheetProtectOnlyFirstRow {
public static void main(String[] args) throws Exception {
Workbook workbook = new XSSFWorkbook();
//create a CellStyle having setLocked false
CellStyle cellstyleUnprotect = workbook.createCellStyle();
cellstyleUnprotect.setLocked(false);
//create a CellStyle having setLocked true
CellStyle cellstyleProtect = workbook.createCellStyle();
cellstyleProtect.setLocked(true);
Sheet sheet = workbook.createSheet("Sheet1");
//set the CellStyle having setLocked false as the default style for all columns
org.openxmlformats.schemas.spreadsheetml.x2006.main.CTCol cTCol =
((XSSFSheet)sheet).getCTWorksheet().getColsArray(0).addNewCol();
cTCol.setMin(1);
cTCol.setMax(16384);
cTCol.setWidth(12.7109375);
cTCol.setStyle(cellstyleUnprotect.getIndex());
Row row = sheet.createRow(0);
//set CustomFormat true for that row
//so it does not using the default style for all columns
//and set the CellStyle having setLocked true as the default style for that row
org.openxmlformats.schemas.spreadsheetml.x2006.main.CTRow cTRow =
((XSSFRow)row).getCTRow();
cTRow.setCustomFormat(true);
cTRow.setS(cellstyleProtect.getIndex());
for (int c = 0; c < 3; c++) {
row.createCell(c).setCellValue("Header " + (c+1));
}
sheet.protectSheet("password"); // protect sheet
workbook.write(new FileOutputStream("CreateExcelSheetProtectOnlyFirstRow.xlsx"));
workbook.close();
}
}