java itext 读取现有 pdf 插里面插入图片 但是源文件内容变空白了 ？？ 求大神 ！！！
PdfReader reader = new PdfReader(newfile);
PdfStamper stamp = new PdfStamper(reader, new FileOutputStream(newfile));
if(!ToolUtils.StringIsEmpty(reportid)){
byte[] code = FileUtils.BarCode(reportid);
if ((code != null) && (code.length > 0)) {
Image img = Image.getInstance(code);
img.setAlignment(Element.ALIGN_LEFT);
img.scaleAbsolute(80,8);
img.setAbsolutePosition(5,10);
for(int i = 1; i <= reader.getNumberOfPages(); i++) {
PdfContentByte under = stamp.getOverContent(i);
under.addImage(img);
}
}
}
stamp.close();
