Apache POI事件API更新现有的Excel工作表

我有几个工作表的大型Excel文件。
我想只处理文件中的一张…从两列读取值并更新两列。

使用这个代码，我能够从sheet中读取数据。但是无法弄清楚，如何保存输出。

public class ExcelFunctions { private class ExcelData implements SheetContentsHandler { private Record rec ; public void startRow(int rowNum) { rec = new Record(); output.put("R"+rowNum, rec); } public void endRow(int rowNum) { } public void cell(String cellReference, String formattedValue, XSSFComment comment) { int thisCol = (new CellReference(cellReference)).getCol(); if(thisCol==7){ try { rec.setK1(formattedValue); } catch (Exception e) { } } if(thisCol==8){ try { rec.setK2(formattedValue); } catch (Exception e) { } } if(thisCol == 27){ String key = rec.full_key(); System.out.println(key); ///////Process Matched Key...get Data //////Set value to column 27 } if(thisCol == 28){ String key = rec.full_key(); System.out.println(key); ///////Process Matched Key...get Data //////Set value to column 28 } } public void headerFooter(String text, boolean isHeader, String tagName) { } } /////////////////////////////////////// private final OPCPackage xlsxPackage; private final Map<String, Record> output; public ExcelFunctions(OPCPackage pkg, Map<String, Record> output) { this.xlsxPackage = pkg; this.output = output; } public void processSheet( StylesTable styles, ReadOnlySharedStringsTable strings, SheetContentsHandler sheetHandler, InputStream sheetInputStream) throws IOException, ParserConfigurationException, SAXException { DataFormatter formatter = new DataFormatter(); InputSource sheetSource = new InputSource(sheetInputStream); try { XMLReader sheetParser = SAXHelper.newXMLReader(); ContentHandler handler = new XSSFSheetXMLHandler( styles, null, strings, sheetHandler, formatter, false); sheetParser.setContentHandler(handler); sheetParser.parse(sheetSource); } catch(ParserConfigurationException e) { throw new RuntimeException("SAX parser appears to be broken - " + e.getMessage()); } } public void process() throws IOException, OpenXML4JException, ParserConfigurationException, SAXException { ReadOnlySharedStringsTable strings = new ReadOnlySharedStringsTable(this.xlsxPackage); XSSFReader xssfReader = new XSSFReader(this.xlsxPackage); StylesTable styles = xssfReader.getStylesTable(); XSSFReader.SheetIterator iter = (XSSFReader.SheetIterator) xssfReader.getSheetsData(); boolean found = false; while (iter.hasNext() && !found) { InputStream stream = iter.next(); String sheetName = iter.getSheetName(); if(sheetName.equals("All Notes") ){ processSheet(styles, strings, new ExcelData(), stream); found = true; } stream.close(); } } @SuppressWarnings("unused") public static void main(String[] args) throws Exception { File xlsxFile = new File("C:\\Users\\admin\\Downloads\\Unique Name Macro\\big.xlsm"); if (!xlsxFile.exists()) { System.err.println("Not found or not a file: " + xlsxFile.getPath()); return; } // The package open is instantaneous, as it should be. OPCPackage p = OPCPackage.open(xlsxFile.getPath(), PackageAccess.READ_WRITE); Map<String, Record> output = new HashMap<String, Record>(); ExcelFunctions xlFunctions = new ExcelFunctions(p, output); xlFunctions.process(); p.close(); if (output != null){ for(Record rec : output.values()){ System.out.println(rec.full_key()); } } } } 

文件非常大，我只想使用Event API。
我已经成功testing使用这个代码。
但是这加载整个文件在内存中（导致应用程序崩溃）…虽然我只需要编辑一张。

  public static void saveToExcel(String ofn, Map<String, Record> data) { FileInputStream infile; try { infile = new FileInputStream(new File("C:\\Users\\admin\\Downloads\\Unique Name Macro\\big.xlsm")); XSSFWorkbook workbook = new XSSFWorkbook (infile); XSSFSheet sheet = workbook.getSheet("All Notes"); for(Record rec : output.values()){ Row dataRow = rec.getRow(rev.getRownum-1); setCellValue(dataRow, 26, "SomeValue"); setCellValue(dataRow, 27, "SomeValue"); } FileOutputStream out = new FileOutputStream(new File(ofn)); workbook.write(out); infile.close(); out.close(); workbook.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } } private static void setCellValue(Row row,int col, String value){ Cell c0 = row.getCell(col); if (c0 == null){ c0 = row.createCell(col); } c0.setCellValue(value); } 

Answer 1

我不认为POI提供了任何开箱即用的function。

因此，通过解压缩XLSX / XLSM文件（它们实际上是zip内的一堆xml文件）并将xml文件作为文本文件或使用正常的XMLparsing器读取，可能会更好。再次写出更改的文件以再次生成XLSX / XLSM文件。