.net 后台读取pdf的值

  string pdfPath = Server.MapPath("~/ViewPatPdf.pdf");
                PDDocument doc = PDDocument.load(pdfPath);
                PDFTextStripper stripper = new PDFTextStripper();
                string txt = stripper.getText(doc);
                Response.Write(txt);

 public string ReadPdfFile(string fileName)
        {
            StringBuilder text = new StringBuilder();
            PdfReader pdfReader = new PdfReader(fileName);
            for (int page = 1; page <= pdfReader.NumberOfPages; page++)
            {
                ITextExtractionStrategy strategy = new SimpleTextExtractionStrategy();
                string currentText = PdfTextExtractor.GetTextFromPage(pdfReader, page, strategy);
                currentText = Encoding.UTF8.GetString(ASCIIEncoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.Default.GetBytes(currentText)));
                text.Append(currentText);
            }
            pdfReader.Close();
            return text.ToString();
        }