code: public Excel07SaxReader read(OPCPackage opcPackage, int sheetIndex) throws POIException {
  		InputStream sheetInputStream = null;
  		try {
  			final XSSFReader xssfReader = new XSSFReader(opcPackage);
  
  			// 获取共享样式表
  			stylesTable = xssfReader.getStylesTable();
  			// 获取共享字符串表
  			this.sharedStringsTable = xssfReader.getSharedStringsTable();
  
  			if (sheetIndex > -1) {
  				this.sheetIndex = sheetIndex;
  				// 根据 rId# 或 rSheet# 查找sheet
  				sheetInputStream = xssfReader.getSheet(RID_PREFIX + (sheetIndex + 1));
  				parse(sheetInputStream);
  			} else {
  				this.sheetIndex = -1;
  				// 遍历所有sheet
  				final Iterator<InputStream> sheetInputStreams = xssfReader.getSheetsData();
  				while (sheetInputStreams.hasNext()) {
  					// 重新读取一个sheet时行归零
  					curRow = 0;
  					this.sheetIndex++;
  					sheetInputStream = sheetInputStreams.next();
  					parse(sheetInputStream);
  				}
  			}
  		} catch (DependencyException e) {
  			throw e;
  		} catch (Exception e) {
  			throw ExceptionUtil.wrap(e, POIException.class);
  		} finally {
  			IoUtil.close(sheetInputStream);
  		}
  		return this;
  	}
docs: 开始读取Excel，Sheet编号从0开始计数
  
  @param opcPackage {@link OPCPackage}，Excel包
  @param sheetIndex Excel中的sheet编号，如果为-1处理所有编号的sheet
  @return this
  @throws POIException POI异常