code: public void processSheet(
              StylesTable styles,
              ReadOnlySharedStringsTable strings,
              SheetContentsHandler sheetHandler,
              InputStream sheetInputStream) throws ReadExcelException {
  
          DataFormatter formatter = new DataFormatter();
          InputSource sheetSource = new InputSource(sheetInputStream);
          try {
              XMLReader sheetParser = SAXHelper.newXMLReader();
              ContentHandler handler = new XSSFSheetXMLHandlerPlus(
                      styles, null, strings, sheetHandler, formatter, false);
              sheetParser.setContentHandler(handler);
              //开始解析
              sheetParser.parse(sheetSource);
          } catch (ParserConfigurationException e) {
              throw new ReadExcelException("SAX parser appears to be broken - " + e.getMessage());
          } catch (Exception e) {
              throw new ReadExcelException(e.getMessage());
          }
      }
docs: 开始解析指定Sheet里的内容
  
  @param styles
  @param strings
  @param sheetHandler
  @param sheetInputStream 指定sheet流
  @throws ReadExcelException