Apache POI for Excel: Setting the cell type to “te

问题:

I need to generate an .xls (Excel) file, using the Java library Apache POI for spreadsheets.

The file will contain a list of phone numbers in column A, formatted as "0221...." or "+49221..." - so Excel by default interprets them as numeric cells. This is bad, because the leading 0 or + will get trimmed.

To solve the problem, I can use cell.setCellType(Cell.CELL_TYPE_STRING), which works fine, but only for the specific cells I set this for.

How can I apply this setting for the entire column (i.e. even for all the remaining cells, where the user will enter additional phone numbers)?

In Excel, this is possible: Selecting the entire column, and apply the cell type (the setting survives saving/loading the file.)

But I can't find the correct method for POI.

• First I assumed, it should be something like sheet.setDefaultCellType(int colNum). But I can't find anything like this (probably I'm just blind? There are lots of similar methods in the library for applying text styles like "align center" etc.)
• Then I thought: Maybe it can only be applied to a NamedRange or something similar, but I haven't managed to work out how this works...

回答1:

Will this help?

By creating a data format with the @ symbol and using that in a CellStyle object that is then passed to the setDefaultColumnStyle() method, it was possible to set the default data type of the column to, in this case, text. I have not experiemented further but do suspect it would be possible to do something similar with other style objects to set the default type to numeric or even a customised format such as currency.

回答2:

Here's some example code inspired by Vlad's answer:

DataFormat fmt = workbook.createDataFormat();
CellStyle textStyle = workbook.createCellStyle();
textStyle.setDataFormat(fmt.getFormat("@"));
worksheet.setDefaultColumnStyle(0, textStyle);

The above code sets the default style for the first column of worksheet to TEXT.

Thanks, Vlad!

回答3:

A better way to set it now using POI is to use the BuiltinFormats class.

Eg:

To convert the column type to numeric

 CellStyle numericStyle = workbook.createCellStyle(); 
 numericStyle.setDataFormat(BuiltinFormats.getBuiltinFormat(2)); // 2 For Number 
 worksheet.setDefaultColumnStyle(colId, numericStyle);

The complete list of BuiltinFormats formats can be seen, here

回答4:

Vlad: This got most of the problem done. I found that all the empty rows were formatted the way I wanted them. However rows where I had initial zeros looked and worked fine; however if I had to change a pre-existing value with another value starting with zero the zeroes disappeared. So I recommend adding code to when you create the value in the cell to reset the the setCellStyle to text. here are some snippets: method public Cell createCell(Row r!, BBjNumber cell, BBjString value!)

c!=#this!.createCell(r!, cell)
c!.setCellValue(value!)
c!.setCellStyle(#text_format!)

methodret c!

#text_format! = #wb!.createCellStyle()
#text_format!.setDataFormat(#format!.getFormat("@"))

methodend

this may help some other sole searching for initial zeroes. Thank you for posting. Alex