Java-如何将地图列表添加到2D对象数组？

Question

我正在构建下面的代码来读取一个Excel文件，并将哈希表列表转换为二维对象数组：

public static Object[][] getTableAsMapObject(String xlFileName, String xlSheetName) throws Exception {
    Map<String, String> dataMap = null;
    ArrayList<Map<String, String>> listOfMaps = new ArrayList<Map<String, String>>();
    Object[][] tabArray = null;

    String masterDataFilePath = "./data/MasterData.xlsx";
    try {
        FileInputStream ExcelFile = new FileInputStream("./data/" + xlFileName + ".xlsx");
        XSSFWorkbook excelWBook = new XSSFWorkbook(ExcelFile);
        XSSFSheet excelWSheet = excelWBook.getSheet(xlSheetName);
        row = excelWSheet.getRow(0);
        int totalCols = row.getLastCellNum();
        totalCols--;
        int startRow = 1;
        int startCol = 1;
        int ci, cj;
        int totalRows = excelWSheet.getLastRowNum();
        int activeRows = 0;
        ci = 0;
        for (int i = startRow; i <= totalRows; i++, ci++) {
            if (getCellData(excelWSheet, i, 0).trim().toUpperCase().equals("YES")
                    || getCellData(excelWSheet, i, 0).trim().toUpperCase().equals("Y")) {
                activeRows++;
            }
        }

        tabArray = new Object[activeRows][0];
        ci = 0;
        for (int i = startRow; i <= totalRows; i++) {// , ci++) {
            cj = 0;
            if (getCellData(excelWSheet, i, 0).trim().toUpperCase().equals("YES")
                    || getCellData(excelWSheet, i, 0).trim().toUpperCase().equals("Y")) {
                dataMap = new HashMap<String, String>();
                for (int j = startCol; j <= totalCols; j++) {

                    String colName = getCellData(excelWSheet, 0, j);
                    if (colName.contains("_")) {
                        String[] bits = colName.split("_");
                        String lastOne = bits[bits.length-1];
                        if (lastOne.equalsIgnoreCase("key")) {
                            dataMap = getMasterDataSet(masterDataFilePath, bits[0], getCellData(excelWSheet, i, j), dataMap);
                        }
                    } else { dataMap.put(colName, getCellData(excelWSheet, i, j)); }
                    cj++;
                }
                listOfMaps.add(dataMap);
                **tabArray = new Object[][] { {dataMap} }; //<== Here I want all the maps in listOfMaps to be added to tabArray**
                dataMap = null;
                ci++;
            }
        }
        excelWBook.close();
    } catch (FileNotFoundException e) {
        System.out.println("Could not read the Excel sheet");
        e.printStackTrace();
    } catch (IOException e) {
        System.out.println("Could not read the Excel sheet");
        e.printStackTrace();
    }
    return (tabArray);
}

我无法将整个地图列表放入对象数组，而是只能获得一张地图。 最终，这应该执行以下操作：

tabArray = new Object[][] { {dataMap1}, {dataMap2}, ... };

Answer 1

只需分解map然后将其输入到Object[][]

Map<String, String> map = new HashMap<>();
Object[][] tabArray = new Object[2][];
tabArray[0] = map.keySet().toArray();
tabArray[1] = map.values().toArray();

JavaDoc中关于keySet()和values()

由于没有执行任何同步，因此，对该方法的多次调用将不会全部返回相同的集合的可能性很小。

Answer 2

以下是对我有用的修改：

public static Object[][] getTableAsMapObject(String xlFileName, String xlSheetName) throws Exception {
        Map<String, String> dataMap = null;
        Object[][] tabArray = null;

        String masterDataFilePath = "./data/MasterData.xlsx";
        try {
            FileInputStream ExcelFile = new FileInputStream("./data/" + xlFileName + ".xlsx");
            // Access the required test data sheet
            XSSFWorkbook excelWBook = new XSSFWorkbook(ExcelFile);
            XSSFSheet excelWSheet = excelWBook.getSheet(xlSheetName);
            row = excelWSheet.getRow(0);
            int totalCols = row.getLastCellNum();
            totalCols--;
            int startRow = 1;
            int startCol = 1;
            int ci;
            int totalRows = excelWSheet.getLastRowNum();
            int activeRows = 0;
            ci = 0;
            for (int i = startRow; i <= totalRows; i++, ci++) {
                if (getCellData(excelWSheet, i, 0).trim().toUpperCase().equals("YES")
                        || getCellData(excelWSheet, i, 0).trim().toUpperCase().equals("Y")) {
                    activeRows++;
                }
            }
            tabArray = new Object[activeRows][1]; //***<<< Changing 0 to 1 did the trick
            ci = 0;
            for (int i = startRow; i <= totalRows; i++) {
                if (getCellData(excelWSheet, i, 0).trim().toUpperCase().equals("YES")
                        || getCellData(excelWSheet, i, 0).trim().toUpperCase().equals("Y")) {
                    dataMap = new HashMap<String, String>();
                    for (int j = startCol; j <= totalCols; j++) {

                        String colName = getCellData(excelWSheet, 0, j);
                        if (colName.contains("_")) {
                            String[] bits = colName.split("_");
                            String lastOne = bits[bits.length-1];
                            if (lastOne.equalsIgnoreCase("key")) {
                                dataMap = getMasterDataSet(masterDataFilePath, bits[0], getCellData(excelWSheet, i, j), dataMap);
                            }
                        } else { dataMap.put(colName, getCellData(excelWSheet, i, j)); }
                    }
                    tabArray[ci][0] = dataMap;
                    dataMap = null;
                    ci++;
                }
            }
            excelWBook.close();
        } catch (FileNotFoundException e) {
            System.out.println("Could not read the Excel sheet");
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("Could not read the Excel sheet");
            e.printStackTrace();
        }
        return (tabArray);
    }