Using ColumnText results in "The document has no pages" exception - itext

Question

I want to wrap text in a rect which is below (or left or right) of a image as below :
Please see link : http://upanh.in/SLk/
I use ColumnText for wrapping text in my code:
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("application/pdf");
try {
// step 1
Document document = new Document(PageSize.A4.rotate());
// step 2
ByteArrayOutputStream baos = new ByteArrayOutputStream();
PdfWriter writer = PdfWriter.getInstance(document, baos);
// step 3
document.open();
// step 4
ColumnText column = new ColumnText(writer.getDirectContent());
column.setSimpleColumn(new Phrase("text is very long ..."), 10, 10, 20, 20, 18, Element.ALIGN_CENTER);
column.go();
// step 5
document.close();
ServletOutputStream os = response.getOutputStream();
baos.writeTo(os);
os.flush();
os.close();
} catch (DocumentException e) {
throw new IOException(e.getMessage());
}
}
Result:
ExceptionConverter: java.io.IOException: The document has no pages.
Do you have any suggestions how to fix that?
Question 2
I try to display text (center and middle) in the rect with below code but it wasn't success. The text was only center in the rect.
ColumnText column = new ColumnText(writer.getDirectContent());
column.setSimpleColumn(RectImg1[0], RectImg1[1], RectImg1[0] + squareHeight, RectImg1[1] + squareHeight
* 1 / 4);
Paragraph p = new Paragraph(imgr.getText(), fontH);
p.setAlignment(Element.ALIGN_CENTER | Element.ALIGN_MIDDLE);
p.setLeading(18);
column.addElement(p);
column.go();
where was my mistake ?

Answer 1

I have edited the title of your question because it was misleading: the exception you encounter will occur in a standalone application too. The fact that you are using the code in a Servlet is irrelevant.
I see that you have the following line:
column.go();
You did not use something like this:
int status = column.go();
If you did, and if you examined status, you would have noticed that the column object still contained some text.
What text? All the text.
There is a serious error in this line:
column.setSimpleColumn(new Phrase("text is very long ..."), 10, 10, 20, 20, 18, Element.ALIGN_CENTER);
You are trying to add the text "text is very long ..." into a rectangle with the following coordinates:
float llx = 10;
float lly = 10;
float urx = 20;
float ury = 20;
You didn't define a font, so the font is Helvetica with font size 12pt and you defined a leading of 18pt.
This means that you are trying to fit text that is 12pt high with an extra 6pt for the leading into a square that measures 10 by 10 pt. Surely you understand that this can't work!
As a result, nothing is added to the PDF and rather than showing an empty page, iText throws an exception saying: there are no pages! You didn't add any content to the document!
You can fix this, for instance by changing the incorrect line into something like this:
column.setSimpleColumn(new Phrase("text is very long ..."), 36, 36, 559, 806, 18, Element.ALIGN_CENTER);
An alternative would be:
column.setSimpleColumn(rect);
column.addElement(paragraph);
In these two lines rect is a Rectangle object. The leading and the alignment are to be defined at the level of the Paragraph object (in this case, you don't use a Phrase).