使用iTextPDF 5.5.4生成PDF时阿拉伯字符显示异常求助

Got it, let's tackle this Arabic text display issue in iTextPDF 5.5.4. I've dealt with similar RTL language problems before, so here's what's going on and how to fix it:

Arabic is a right-to-left (RTL) language with unique ligature behavior—letters connect differently based on their position in a word. Even though Arial Unicode MS (ARIALUNI.ttf) supports Arabic characters, iText 5.x doesn’t handle RTL layout or ligatures automatically. You need to explicitly configure these settings to get proper rendering.

1. Confirm Font Setup is Correct #

First, double-check your BaseFont creation uses the right Unicode encoding. Your existing code should look something like this, but verify these key details:

BaseFont baseFont = BaseFont.createFont("/fonts/ARIALUNI.ttf", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
Font arabicFont = new Font(baseFont, 12);

• IDENTITY_H is critical: It tells iText to use Unicode horizontal encoding, which supports all characters in Arial Unicode MS.
• BaseFont.EMBEDDED ensures the font is packaged with the PDF, so readers don’t substitute it with a non-Arabic font.

2. Force RTL Text Direction #

This is the most common fix. You need to tell iText to render Arabic text from right to left, depending on what element you’re using:

For Paragraphs: #

String arabicContent = "مثال نص عربي لاختبار";
Paragraph arabicPara = new Paragraph(arabicContent, arabicFont);
arabicPara.setRunDirection(PdfWriter.RUN_DIRECTION_RTL);
document.add(arabicPara);

For Table Cells (PdfPCell): #

PdfPCell cell = new PdfPCell(new Phrase(arabicContent, arabicFont));
cell.setRunDirection(PdfWriter.RUN_DIRECTION_RTL);
yourTable.addCell(cell);

3. Fix Ligature Issues (If Letters Are Disconnected) #

If Arabic letters show up as separate characters instead of connected ligatures, use iText’s ArabicLigaturizer to process the text first:

ArabicLigaturizer ligaturizer = new ArabicLigaturizer();
String processedArabic = ligaturizer.process(arabicContent);
Paragraph arabicPara = new Paragraph(processedArabic, arabicFont);
arabicPara.setRunDirection(PdfWriter.RUN_DIRECTION_RTL);
document.add(arabicPara);

This ensures connected letters render as proper, natural ligatures.

4. Troubleshoot Common Edge Cases #

• Text is reversed but letters are correct: You forgot to set RUN_DIRECTION_RTL.
• Text is missing entirely: Double-check your font file path is correct (use absolute paths if needed) and that ARIALUNI.ttf isn’t corrupted.
• Ligatures still look off: Some complex Arabic script might need additional handling, but ArabicLigaturizer covers most standard cases in iText 5.5.4.

内容的提问来源于stack exchange，提问作者curious1