code: public String readAsText(boolean withSheetName) {
  		final ExcelExtractor extractor = getExtractor();
  		extractor.setIncludeSheetNames(withSheetName);
  		return extractor.getText();
  	}
docs: 读取为文本格式<br>
  使用{@link ExcelExtractor} 提取Excel内容
  
  @param withSheetName 是否附带sheet名
  @return Excel文本
  @since 4.1.0