iText 生成PDF 报错的问题
代码大致如下:

FileOutputStream fileOutputStream = null;
PdfWriter write = null;
try {
fileOutputStream = new FileOutputStream(outputFilePath);
Document document = new Document(PageSize.A4, 50, 50, 50, 50);
write = PdfWriter.getInstance(document, fileOutputStream);
write.open();
Paragraph p1 = new Paragraph();
p1.add(contentBuffer.toString());
document.add(p1);
} catch (IOException e) {
e.printStackTrace();
} catch (DocumentException e) {
e.printStackTrace();
}

结果报了个错：com.itextpdf.text.DocumentException: The document is not open yet; you can only add Meta information.

我调试的时候发现 document的isOpen方法返回 false PDF
[解决办法]
document.open();