code: @Override
  	public void open(FileInputSplit split) throws IOException {
  		// read Excel
  		super.open(split);
  		// infer schema (requires to read file again)
  		if (this.customSchema == null) {
  			ExcelFlinkFileInputFormat effif = new ExcelFlinkFileInputFormat(this.shocr);
  			effif.open(split);
  			SpreadSheetCellDAO[] currentRow = effif.nextRecord(null);
  			int i = 0;
  			while ((currentRow != null) && (i != this.maxInferRows)) {
  				this.converter.updateSpreadSheetCellRowToInferSchemaInformation(currentRow);
  				i++;
  				currentRow = effif.nextRecord(null);
  			}
  			effif.close();
  			this.customSchema = this.converter.getSchemaRow();
  		} else {
  			this.converter.setSchemaRow(this.customSchema);
  		}
  	}
docs: Open an Excel file
  
  @param split
  contains the Excel file