excel 中的每一行中都插入了相同的数据，即使结果集使用 java 具有不同的数据

Question

我需要将数据导出到 excel。

我写了一个传递查询结果的方法，即集合对象和字符串数组 - 属性 LinkedHashMap<Integer, Object[]>。方法如下所示。每个条目的结果存储在对象数组中并插入到一个键中。返回的结果现在在 resultSet 中并通过另一个方法传递 processReport(resultSet).

LinkedHashMap<Integer, Object[]> resultSet = dqlHelper.insertAttrValues(collection,
        attrs);

processReport(resultSet);

public LinkedHashMap<Integer, Object[]> insertAttrValues(IDfCollection collection,
                                                         String[] properties) throws DfException {

    if (collection == null || properties == null) {
        throw new MissingParameterException("collection and properties");
    }

    LinkedHashMap<Integer, Object[]> map = new LinkedHashMap<>();
    Object[] values = new Object[properties.length];

    int i = 0;
    while (collection.next()) {
        for (int x = 0; x < properties.length; x++) {
            values[x] = collection.getString(properties[x]);
        }
        map.put(i++, values);
    }
    return map;
}

方法processReport(resultSet); 此方法获取resultSet并将数据写入excel。但是在每一行中，我得到的数据与方法中的注释中所示的数据相同。但是 resultSet 的结果包含所有数据。不知道在哪里，我做错了。非常感谢任何帮助。

private void processReport(LinkedHashMap<Integer, Object[]> resultSet)
            throws IOException {
        // Create a Workbook - for xlsx
        Workbook workbook = new XSSFWorkbook();

         /* CreationHelper helps us create instances of various things like DataFormat,
           Hyperlink, RichTextString etc, in a format (HSSF, XSSF) independent way
        */
        workbook.getCreationHelper();

        // Create a Sheet
        Sheet sheet = workbook.createSheet("Report");

        // Create a Font for styling header cells
        Font headerFont = workbook.createFont();
        headerFont.setBold(false);
        headerFont.setFontHeightInPoints((short) 12);
        headerFont.setColor(IndexedColors.GREEN.getIndex());

        // Create a CellStyle with the font
        CellStyle headerCellStyle  = workbook.createCellStyle();
        headerCellStyle.setFont(headerFont);

        // Create a Row
        Row headerRow = sheet.createRow(0);
        // Create cells
        for (int i = 0; i < attrs.length; i++) {
            Cell cell = headerRow.createCell(i);
            cell.setCellValue(redigo_attrs[i]);
            cell.setCellStyle(headerCellStyle);
        }

        // Facing problem in the following code.....
        // same entry in every row in excel sheet
        // 0902b69881bd01a5     NLP_031124  VPS17_BR-NPI-EN-GILENYA_-06.06.19_MS_(clean)    Brazil  Gilenya
        // 0902b69881bd01a5     NLP_031124  VPS17_BR-NPI-EN-GILENYA_-06.06.19_MS_(clean)    Brazil  Gilenya

        Set<Integer> key_set = resultSet.keySet();
        sheet = workbook.getSheetAt(0);
        for (Integer key: key_set) {
            int last_row = sheet.getLastRowNum();
            row = sheet.createRow(++last_row);
            int cellNum = 0;
            Object[] valuesObject = resultSet.get(key);
            for (Object value: valuesObject) {
                row.createCell(cellNum++).setCellValue(value.toString());
            }
        }

        // Resize all columns to fit the content size
        for (int i = 0; i < attrs.length; i++) {
            sheet.autoSizeColumn(i);
        }
        // Write the output to the file
        FileOutputStream fileOutputStream = new FileOutputStream(XLSX_FILE_PATH);
        workbook.write(fileOutputStream);
        // close the file
        fileOutputStream.close();
        // close the workbook
        workbook.close();
    }

Answer 1

您正在将对同一个数组 (values) 的引用放在一边。因此，所有 LinkedHashMap 值都是对包含结果集中最后一行的同一数组的引用。

您需要为每一行创建不同的数组对象：

//remove this line
//Object[] values = new Object[properties.length];

int i = 0;
while (collection.next()) {
    //put it here
    Object[] values = new Object[properties.length];
    for (int x = 0; x < properties.length; x++) {
        values[x] = collection.getString(properties[x]);
    }
    map.put(i++, values);
}

P.S。请阅读 How to create a Minimal, Reproducible Example and How to debug small programs。

excel 中的每一行中都插入了相同的数据，即使结果集使用 java 具有不同的数据

Same data is getting inserted in every row in excel even though the result set has different data using java

java

set

linkedhashmap

apache-poi