开始读取指定行的Excel工作表

我正在阅读使用POI的XSSF和SAX（事件API）的Excel文件。 Excel工作表有成千上万行，所以这是我发现有良好性能的唯一方法。 现在我想从一个特别的行读取Excel文件，例如第6行，因为这些Excel文件每天都会更新，而且我存储了最后一行，因此我只能读取新行。

我如何从一行开始？

private void getExcelField(AcquisitionForm acquisitionForm) throws ExcelReadException, IOException{ InputStream stream=null; OPCPackage p=null; try{ p = OPCPackage.open(acquisitionForm.getDatatablePath(), PackageAccess.READ); ReadOnlySharedStringsTable strings = new ReadOnlySharedStringsTable(p); XSSFReader xssfReader = new XSSFReader(p); StylesTable styles = xssfReader.getStylesTable(); XSSFReader.SheetIterator iter = (XSSFReader.SheetIterator) xssfReader.getSheetsData(); int index = 0; //Test with one sheet iter.hasNext(); //(iter.hasNext()) { stream = iter.next(); String sheetName = iter.getSheetName(); processSheet(styles, strings, stream, acquisitionForm); stream.close(); //++index; //} p.close(); }catch(Exception e){ throw new ExcelReadException("An error occured during excel file reading ", e); }finally{ if (stream!=null) stream.close(); if (p!=null) p.close(); //++index; // } } } /** * Parses and shows the content of one sheet * using the specified styles and shared-strings tables. * @param styles * @param strings * @param sheetInputStream * @throws ExcelReadException */ private void processSheet(StylesTable styles, ReadOnlySharedStringsTable strings, InputStream sheetInputStream, AcquisitionForm acquisitionForm) throws Exception { InputSource sheetSource = new InputSource(sheetInputStream); SAXParserFactory saxFactory = SAXParserFactory.newInstance(); SAXParser saxParser = saxFactory.newSAXParser(); XMLReader sheetParser = saxParser.getXMLReader(); //ContentHandler handler = new MyXSSFSheetHandler(styles, strings); MyXSSFSheetHandler handler = new MyXSSFSheetHandler(styles, strings,databaseAcquisitionServices, acquisitionForm); sheetParser.setContentHandler(handler); sheetParser.parse(sheetSource); } 

MyXSSFSheetHandler

 public MyXSSFSheetHandler(StylesTable styles, ReadOnlySharedStringsTable strings,DatabaseAcquisitionServices databaseAcquisitionServices, AcquisitionForm acquisitionForm, int sheetIndex) { this.stylesTable = styles; this.sharedStringsTable = strings; this.formatter = new DataFormatter(); this.value = new StringBuffer(); this.nextDataType = XssfDataType.NUMBER; this.databaseAcquisitionServices=databaseAcquisitionServices; this.acquisitionForm=acquisitionForm; this.sheetIndex = sheetIndex; } /** * */ public void startElement(String uri, String localName, String name, Attributes attributes) throws SAXException { if ("inlineStr".equals(name) || "v".equals(name)) { vIsOpen = true; // Clear contents cache value.setLength(0); } // c => cell else if ("c".equals(name)) { // Get the cell reference cellCoordinate = attributes.getValue("r"); int firstDigit = -1; for (int c = 0; c < cellCoordinate.length(); ++c) { if (Character.isDigit(cellCoordinate.charAt(c))) { firstDigit = c; break; } } thisColumn = nameToColumn(cellCoordinate.substring(0, firstDigit)); // Set up defaults. this.nextDataType = XssfDataType.NUMBER; this.formatIndex = -1; this.formatString = null; String cellType = attributes.getValue("t"); String cellStyleStr = attributes.getValue("s"); if ("b".equals(cellType)) { nextDataType = XssfDataType.BOOL; } else if ("e".equals(cellType)) { nextDataType = XssfDataType.ERROR; } else if ("inlineStr".equals(cellType)) { nextDataType = XssfDataType.INLINESTR; } else if ("s".equals(cellType)) { nextDataType = XssfDataType.SSTINDEX; } else if ("str".equals(cellType)) { nextDataType = XssfDataType.FORMULA; } else if (cellStyleStr != null) { // It's a number, but almost certainly one // with a special style or format int styleIndex = Integer.parseInt(cellStyleStr); XSSFCellStyle style = stylesTable.getStyleAt(styleIndex); this.formatIndex = style.getDataFormat(); this.formatString = style.getDataFormatString(); if (this.formatString == null) { this.formatString = BuiltinFormats.getBuiltinFormat(this.formatIndex); } } } } /* * (non-Javadoc) * @see org.xml.sax.helpers.DefaultHandler#endElement(java.lang.String, java.lang.String, java.lang.String) */ public void endElement(String uri, String localName, String name) throws SAXException { String cellValue = null; //String thisStr = null; // v => contents of a cell if ("v".equals(name)) { // Process the value contents as required. // Do now, as characters() may be called more than once switch (nextDataType) { case BOOL: char first = value.charAt(0); //thisStr = first == '0' ? "FALSE" : "TRUE"; //cellValue= new Boolean(first =='0' ? false: true); cellValue=first == '0' ? "false" : "true"; break; case ERROR: //thisStr = "\"ERROR:" + value.toString() + '"'; cellValue=new String(value.toString()); break; case FORMULA: // A formula could result in a string value, // so always add double-quote characters. //thisStr = '"' + value.toString() + '"'; cellValue=new String(value.toString()); break; case INLINESTR: XSSFRichTextString rtsi = new XSSFRichTextString(value.toString()); //thisStr = '"' + rtsi.toString() + '"'; cellValue=new String(rtsi.toString()); break; case SSTINDEX: String sstIndex = value.toString(); try { int idx = Integer.parseInt(sstIndex); XSSFRichTextString rtss = new XSSFRichTextString(sharedStringsTable.getEntryAt(idx)); // thisStr = '"' + rtss.toString() + '"'; cellValue=new String(rtss.toString()); } catch (NumberFormatException ex) { System.out.println("Failed to parse SST index '" + sstIndex + "': " + ex.toString()); } break; case NUMBER: String n = value.toString(); if (this.formatString != null && n.length() > 0){ cellValue = formatter.formatRawCellContents(Double.parseDouble(n), this.formatIndex, this.formatString); //cellValue=new Double(Double.parseDouble(n)); } else{ //thisStr = n; cellValue=new String(n); } break; default: cellValue=""; //thisStr = "(TODO: Unexpected type: " + nextDataType + ")"; break; } // Output after we've seen the string contents // Emit commas for any fields that were missing on this row if (lastColumnNumber == -1) { lastColumnNumber = 0; } // for (int i = lastColumnNumber; i < thisColumn; ++i){ // System.out.print(','); // } // Might be the empty string. rowValues.put(cellCoordinate,cellValue); //System.out.print(cellValue); // Update column if (thisColumn > -1) lastColumnNumber = thisColumn; } else if ("row".equals(name)) { // We're onto a new row //I have to pass new HashMap because otherwise all the map into archiveAcquisition have the same values databaseAcquisitionServices.archiveAcquisition(new TreeMap<>(rowValues), rowCounter, acquisitionForm, sheetIndex); //Clear the structure used to store row data rowValues.clear(); rowCounter++; //System.out.println(); lastColumnNumber = -1; } } /** * Captures characters only if a suitable element is open. * Originally was just "v"; extended for inlineStr also. */ public void characters(char[] ch, int start, int length) throws SAXException { if (vIsOpen) value.append(ch, start, length); } /** * Converts an Excel column name like "C" to a zero-based index. * * @param name * @return Index corresponding to the specified name */ private int nameToColumn(String name) { int column = -1; for (int i = 0; i < name.length(); ++i) { int c = name.charAt(i); column = (column + 1) * 26 + c - 'A'; } return column; } 

Answer 1

您可能需要计算从SheetContentsHandler派生的类中看到的行数，我不认为您需要单独的XSSFSheetHAndler ，我宁愿使用默认值，只有一个带有callback的SheetContentsHandler ，所有你感兴趣的东西的方法，例如startRow ， endRow ， cell 。

您可以看一下XLSX2CSV示例 ，了解如何对XLSX文件进行stream式读取，特别是如何使用SheetToCSV类来调用每行/单元格，例如可以使用if (currentRow < startRow) { return }在方法cell()中跳过行。

cell-method用参数String cellReference ，可以通过new CellReference(cellReference).getCol()和new CellReference(cellReference).getRow()获取行/单元坐标。