XWPFDocument：更改文档的字体大小

Question

我想将docx文档的字体大小（更改为12）

XWPFDocument document = new XWPFDocument(new FileInputStream("temp_"+idConsultant+".docx"));
List<XWPFParagraph> paragraphs = document.getParagraphs();

for (XWPFParagraph para : paragraphs) {
    for (XWPFRun run : para.getRuns()) {
        run.setFontSize(12);
    }
}
document.write(new FileOutputStream(fileName));
fis.close();

它不起作用，字体大小没有改变