Java POI excel paging sheets - java

I'm working on a excel workbook, using Java POI.
I have several sheets and I need to add Pagination to 4 of them.
The problem is :
How I am suppose to attribute a global pagination to these sheets ?
sheet.getFooter().setRight(HeaderFooter.page()); only works for ONE sheet.
Cordially.

The Excel file format mandates that a footer is always per sheet, even in Excel itself you have to set up the footer for each sheet separately as far as I know. So the Apache POI API reflects this and you need to set the footer for each sheet.
Naturally you can write a helper function where you pass in the Sheet object to not have to code it 4 times here.

Related

Apache poi not finding a hidden sheet

I am trying an example to learn the Apache POI library. In the example I am using a Test.xls excel sheet which has the 3rd sheet as hidden.
So I am assuming that when I use "workbook.getNumberOfSheets()" the result will be including the hidden sheet, which in my case should be 3.
But, I keep getting 2 as the result. I want to know how can I find the actual number of sheets incase there is/are hidden sheet in the excel.
Since in the actual use case I will not know the excel before hand, I would like to know the total number of sheets.
Any help is appreciated and thank you in advance.

Read empty cell using Apache POI Event model

I have a huge excel file with tons of columns which looks like this :-
Column1 Column2 Column3 Column4 Column5
abc def ghi
mno pqr
......
The output generated by my code when I print all the values in excel is :-
abc;def;ghi;null;null
mno;pqr;null;null;null
So, If we look at the output above we can note that the cells where I left blank values were not picked up by the POI library. Is there a way in which I can get these values as null? Or a way to recognize that the values presented skipped blank cells?
Please note: I am not using the usermodel (org.apache.poi.ss.usermodel) but an Event API to process xls and xlsx files.
I am implementing HSSFListener and overriding its processRecord(Record record) method for xls files. For xlsx files I am using javax.xml.parsers.SAXParser and org.xml.sax.XMLReader.
I am using JDK7 with Apache POI 3.7. Can someone please help?
I have already seen this possible duplicate How to get an Excel Blank Cell Value in Apache POI? But this doesn't answer my question as I am using Event API.
Yes, it can be done, and there are several examples of it which ship with Apache POI. They all relate to Event based xls / xlsx -> CSV, which looks very close to what you're doing. That makes me worry you may be re-inventing the wheel...
For HSSF event model processing, the example you want to look at is XLS2CSVmra. That is powered by MissingRecordAwareHSSFListener
For XSSF event model, the example you need is XLSX2CSV

Using Apache POI can I stop users copying formatting?

I have made an excel sheet which is generated by Java. The cells can only accept certain values, depending on data validation done against lists on a separate sheet.
This all works great, but if a user copies some values from another cell and pastes it into the cell it avoids validation... is there any way to prevent this?
You can do this by setting data format for that cell.
style = wb.createCellStyle();
style.setDataFormat(wb.createDataFormat().getFormat("0.000%"));
which will percentage value.
For documentation goto:
Apache HSSF Doc

API for Processing large XLSX file

I have one question. Is there any API that can process xlsx and xls file. The requirement is i have one excel file. i have to encrypt values of some specific columns. without affecting the format of cell like cell color, cell formula, cell date format, cell currency format, charts etc. I have used APACHE POI library. i did not get success. it is very slow and not working on large file. i also searched on google but i dint get proper result.
An alternative to POI is JXL.
We used it successfully with rather large files.

File size issue. while poi read write

I am using apache poi api to deal with my spread sheet files.
I have observed, if we try to edit an existing .xls file it size is not the same as if that same file (same data ) is written in one go.
It is normal for an Excel spreadsheet to grow after being opened or edited. When a spreadsheet is opened in Microsoft Excel the formulas are automatically calculated, so this increases the size of the file. If a spreadsheet is opened by Apache POI it is up to the developer to call the (FormulaEvaluator) to update all the values. When a spreadsheet is read by Apache POI and the formulas have not been evaluated, formula answers may be invalid.
POI will always write out one record per cell
Excel, however, will sometimes bunch several similar sequential cells up into a single record. For example, if you have 3 cells in a row that are blank but styled, then excel will generate a MulBlankRecord which holds all of them. For several cells in a row with simple numbers in them, excel uses a MulRKRecord
When POI reads in a file, it expands all the Mul* records out. At write time, the individual cell records are written, so the file gets slightly bigger. I think there's an entry in the POI bugzilla for the enhancement to get POI to coalesce cells into Mul records, but no-one seems to have volunteered to work on it yet...

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