how to write Chinese characters

[Jian Shen]

    
I am new to PDFBox, and I couldn't figure out how to write Chinese characters 
to pdf file. With the code snippet below, the result pdf file displays some 
squares and strange symbols, instead of the correct Chinese character. And 
Acrobat Reader pops up a message, saying "The font '??' contains bad /Widths." 

            PDFont font = PDTrueTypeFont.loadTTF(document, 
"C:\\Windows\\fonts\\simkai.ttf");
            PDPageContentStream contentStream = new 
PDPageContentStream(document, page);
            
            contentStream.beginText();
            contentStream.setFont(font, 12);
            contentStream.moveTextPositionByAmount(100, 700);
            contentStream.drawString("\u59D3");
            contentStream.endText();


What am I missing? Is there a code sample for generating PDF files with Asian 
characters?


Thanks!
-Jian