动态添加外部（跨工作簿）引用

Question

在我们的项目中，我们有不同版本的 excelsheets 相互引用：

C:\V1\Sample.xls //没有引用

C:\V2\Sample.xls //引用 V1

C:\V3\Sample.xls //引用 V2

单元格值示例：

=MID('C:\V1\[Sample.xls]Sheet1'!$AB2;21;1)

现在我想使用apache POI评估V3的公式，我找到了以下示例here

// Create a FormulaEvaluator to use
FormulaEvaluator mainWorkbookEvaluator = workbook.getCreationHelper().createFormulaEvaluator();

// Track the workbook references
Map<String,FormulaEvaluator> workbooks = new HashMap<String, FormulaEvaluator>();
// Add this workbook
workbooks.put("report.xlsx", mainWorkbookEvaluator);
// Add two others
workbooks.put("input.xls", WorkbookFactory.create("c:\temp\input22.xls").getCreationHelper().createFormulaEvaluator());
workbooks.put("lookups.xlsx", WorkbookFactory.create("/home/poi/data/tmp-lookups.xlsx").getCreationHelper().createFormulaEvaluator());

// Attach them
mainWorkbookEvaluator.setupReferencedWorkbooks(workbooks);

// Evaluate
mainWorkbookEvaluator.evaluateAll();

现在我的问题：我不知道文件的位置，因此我需要从 mainworkbook 获取所有引用，然后自动（并且可能递归地）添加它们，而不是像在上面的例子。是否有获取参考的功能，或者有人知道实现此目的的方法吗？

另外，我想知道是否必须将所有 FormulaEvaluator 添加到 V3，还是必须将 V2 添加到 V3 和 V1 到 V2 才能工作？

我目前已经实现了 setIgnoreMissingWorkbooks(true)，但是由于值会改变，我们不想手动打开每个 excel 文件来更新我想要实现这个解决方案的引用。任何帮助表示赞赏

Answer 1

要获取所有外部引用，请使用以下方法：

private static Set<String> getReferencedWorkbooks(Workbook workbook) {
    Set<String> workbookNames = new HashSet<>();
    final EvaluationWorkbook evalWorkbook;
    if (workbook instanceof HSSFWorkbook) {
        evalWorkbook = HSSFEvaluationWorkbook.create((HSSFWorkbook) workbook);
    } else if (workbook instanceof XSSFWorkbook) {
        evalWorkbook = XSSFEvaluationWorkbook.create((XSSFWorkbook) workbook);
    } else {
        throw new IllegalStateException();
    }
    for (int i = 0; i < workbook.getNumberOfSheets(); i++) {
        Sheet sheet = workbook.getSheetAt(i);
        final EvaluationSheet evalSheet = evalWorkbook.getSheet(i);
        for (Row r : sheet) {
            for (Cell c : r) {
                if (c.getCellType() == HSSFCell.CELL_TYPE_FORMULA) {
                    final EvaluationCell cell = evalSheet.getCell(c.getRowIndex(), c.getColumnIndex());
                    final Ptg[] formulaTokens = evalWorkbook.getFormulaTokens(cell);
                    for (Ptg formulaToken : formulaTokens) {
                        final int externalSheetIndex;
                        if (formulaToken instanceof Ref3DPtg) {
                            Ref3DPtg refToken = (Ref3DPtg) formulaToken;
                            externalSheetIndex = refToken.getExternSheetIndex();
                        } else if (formulaToken instanceof Ref3DPxg) {
                            Ref3DPxg refToken = (Ref3DPxg) formulaToken;
                            externalSheetIndex = refToken.getExternalWorkbookNumber();
                        } else {
                            externalSheetIndex = -1;
                        }

                        if (externalSheetIndex >= 0) {
                            final ExternalSheet externalSheet = evalWorkbook.getExternalSheet(externalSheetIndex);
                            workbookNames.add(externalSheet.getWorkbookName());
                        }
                    }
                }
            }
        }
    }
    return workbookNames;
}

如果您所有的工作簿都是 XLSX/XLSM，您可以使用以下代码：

private static Set<String> getReferencedWorkbooksXssf(XSSFWorkbook workbook) {
    Set<String> workbookNames = new HashSet<>();
    final List<ExternalLinksTable> externalLinksTable = workbook.getExternalLinksTable();
    for (ExternalLinksTable linksTable : externalLinksTable) {
        final String linkedFileName = linksTable.getLinkedFileName();
        workbookNames.add(linkedFileName);
    }

    return workbookNames;
}