public static void main(String[] args) {
        System.out.println(FileUtils.exists("invoice/2017011817151260118001.pdf"));
System.out.println(FileUtils.exists("invoice/20170118/2017011817151260118001.pdf"));
InputStream inputStream=FileUtils.getFileStream("invoice/20170118/2017011817151260118001.pdf");//從伺服器上讀dpf檔案
        byte
 
[] b = new byte[1024];
        int a=0;
        try {
            //FileOutputStream fo = new FileOutputStream("D:/test/a.pdf");
FileOutputStream fo = new FileOutputStream("D:/test/wj.pdf");
// String str=convertStreamToString(inputStream);
            //Document document = new Document();
//            while((a = inputStream.read(b)) != -1){
 
//                fo.write(a);
//
//            }
ByteArrayOutputStream baos = new ByteArrayOutputStream();
            for(int i;(i=inputStream.read())!=-1;)
            {
                baos.write(i);
}
            baos.flush();
Document doc = new Document();
PdfStream pdfStream=new PdfStream(baos.toByteArray());
 
PdfWriter pw =PdfWriter.getInstance(doc, fo);  //
pdfStream.toPdf(pw,fo);
System.out.println(doc.newPage());
pw.flush();
baos.close();
pw.close();
fo.close();
//doc.close();
inputStream.close();
} catch (IOException e) {
            e.printStackTrace();
} catch (DocumentException e) {
            e.printStackTrace();
}
        System.out.println();
}