用 sax 解析器的 endElement 覆盖 HashMap 变量

Question

我一直在使用 SAX 解析器从 Excel sheet 中读取数据，但我遇到了问题。我需要保存前四行然后迭代其他行，但是当我将初始行保存到不同的 HashMap 时，这些被覆盖，我在所有结构中获得相同的字段。

这是endElement方法的代码：

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);
            cellValue=first == '0' ? "false" : "true";
            break;

        case ERROR:
            cellValue=new String(value.toString());
            break;

        case FORMULA:
            // A formula could result in a string value,
            // so always add double-quote characters.
            cellValue=new String(value.toString());
            break;

        case INLINESTR:
            XSSFRichTextString rtsi = new XSSFRichTextString(value.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));
                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);
            }
            else{
                cellValue=new String(n);
            }
            break;

        default:
            cellValue="";
            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;
        }

        // Might be the empty string.
        rowValues.put(cellCoordinate,cellValue);

        // Update column
        if (thisColumn > -1)
            lastColumnNumber = thisColumn;

    } else if ("row".equals(name)) {
        // We're onto a new row
        databaseServices.archiveAcquisition(rowValues,rowCount);
        //Clear the structure used to store row data
        rowValues.clear();
        rowCount++;
        lastColumnNumber = -1;
    }
}

和archiveAcquisition方法：

@Override
public void archiveAcquisition(HashMap<String,String> actualRowValues, int index) {
    switch(index){
    case 1:
        firstRowValues=actualRowValues;
        break;
    case 2:
        secondRowValues=actualRowValues;
        break;
    case 3:
        thirdRowValues=actualRowValues;
        break;
    default:
        //CREATE ALL THE OBJECT TO STORE THE ACQUISITION
        //Create shift object, if it already exists, it'll be updated
        Shift shift=new Shift(actualRowValues.get(ExcelMappingCoordinate.shift.getCoordinate()+index));
        shiftServices.create(shift);

我不明白问题出在哪里，SAX 库的隐藏行为？我也尝试过将外部对象存储在哪里，但问题是一样的。

Answer 1

问题是重复添加了同一个 HashMap 对象 (rowValues)，在中间清除了它。

一个快速的破解方法是每次都制作地图的副本：

databaseServices.archiveAcquisition(new HashMap<>(rowValues),rowCount);

最好从一个新的 rowValues 开始，也许作为局部变量。

用 sax 解析器的 endElement 覆盖 HashMap 变量

Overrided HashMap variable with endElement of sax parser

java

excel

sax

hashmap

overwrite