aspose实现Office转Pdf关键代码： 

protected void realTransform(InputStream in, OutputStream out) throws IOException    {      String lowerFileName = this.fileName.toLowerCase();      try {        if ((lowerFileName.endsWith(".xls")) || (lowerFileName.endsWith(".xlsx")) || (lowerFileName.endsWith(".csv"))) {          Workbook workbook = new Workbook(in);          workbook.save(out, 13);        } else if ((lowerFileName.endsWith(".doc")) || (lowerFileName.endsWith(".docx")) || (lowerFileName.endsWith(".rtf"))) {          Document doc = new Document(in);          doc.save(out, 40);        } else if ((lowerFileName.endsWith(".ppt")) || (lowerFileName.endsWith(".pptx")) || (lowerFileName.endsWith(".pps")) || (lowerFileName.endsWith(".ppsx")))        {          Presentation ppt = new Presentation(in);          ppt.save(out, 1);        } else if ((lowerFileName.endsWith(".vdx")) || (lowerFileName.endsWith(".vsx")) || (lowerFileName.endsWith(".vtx")) || (lowerFileName.endsWith(".vsd")))        {          Diagram visio = new Diagram(in);          visio.save(out, 8);        }      } catch (Exception ex) {        throw new RuntimeException(ex);      }    }