Apache POI SAX XSSFReader读取错误的日期格式

Question

Apache POI SAX读取器的实现类似于此众所周知的示例，https://github.com/pjfanning/poi-shared-strings-sample/blob/master/src/main/java/com/github/pjfanning/poi/sample/XLSX2CSV.java读取的某些日期值不像excel中显示的那样，尽管它们应该读取“格式化值”。

Excel文件中的值：1/1/2019，阅读器读取的“格式化值”：1/1/19。

知道为什么会有区别吗？

Apache POI版本3.17

阅读器代码：

package com.lopuch.sk.lita.is.importer;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;

import javax.xml.parsers.ParserConfigurationException;

import org.apache.log4j.Logger;
import org.apache.poi.openxml4j.exceptions.OpenXML4JException;
import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.openxml4j.util.ZipSecureFile;
import org.apache.poi.ss.usermodel.DataFormatter;
import org.apache.poi.ss.util.CellAddress;
import org.apache.poi.ss.util.CellReference;
import org.apache.poi.util.SAXHelper;
import org.apache.poi.xssf.eventusermodel.ReadOnlySharedStringsTable;
import org.apache.poi.xssf.eventusermodel.XSSFReader;
import org.apache.poi.xssf.eventusermodel.XSSFSheetXMLHandler;
import org.apache.poi.xssf.eventusermodel.XSSFSheetXMLHandler.SheetContentsHandler;
import org.apache.poi.xssf.model.StylesTable;
import org.apache.poi.xssf.usermodel.XSSFComment;
import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;

import com.lopuch.sk.lita.is.importer.fileImport.ExcelRowReadListener;

public class ExcelSaxImporter {

    private static final Logger logger = Logger.getLogger(ExcelSaxImporter.class);

    private ExcelRowReadListener listener;

    public void setOnRowRead(ExcelRowReadListener listener) {
        this.listener = listener;
    }

    public ExcelRowReadListener getListener() {
        return listener;
    };

    public void process(byte[] fileByteArray)
            throws IOException, OpenXML4JException, ParserConfigurationException, SAXException {
        ZipSecureFile.setMinInflateRatio(0.0d);
        OPCPackage opcpPackage = OPCPackage.open(new ByteArrayInputStream(fileByteArray));
        ReadOnlySharedStringsTable strings = new ReadOnlySharedStringsTable(opcpPackage);
        XSSFReader xssfReader = new XSSFReader(opcpPackage);
        StylesTable styles = xssfReader.getStylesTable();
        XSSFReader.SheetIterator iter = (XSSFReader.SheetIterator) xssfReader.getSheetsData();

        while (iter.hasNext()) {
            InputStream stream = iter.next();
            processSheet(styles, strings, getHandler(), stream);
            stream.close();
        }
    }

    private SheetContentsHandler getHandler() {
        return new SheetContentsHandler() {

            private boolean firstCellOfRow = false;
            private int currentRow = -1;
            private int currentCol = -1;

            // Maps column Letter name to its value.
            // Does not contain key-value pair if cell value is null for
            // currently
            // processed column and row.
            private Map<String, String> rowValues;

            @Override
            public void startRow(int rowNum) {
                // Prepare for this row
                firstCellOfRow = true;
                currentRow = rowNum;
                currentCol = -1;
                rowValues = new HashMap<String, String>();
            }

            @Override
            public void endRow(int rowNum) {
                if (rowValues.keySet().size() == 0) {
                    logger.trace("Skipping calling rowRead() because of empty row");
                } else {
                    ExcelSaxImporter.this.getListener().rowRead(rowValues);
                }
            }

            @Override
            public void cell(String cellReference, String formattedValue, XSSFComment comment) {
                if (firstCellOfRow) {
                    firstCellOfRow = false;
                }

                // gracefully handle missing CellRef here in a similar way
                // as XSSFCell does
                if (cellReference == null) {
                    cellReference = new CellAddress(currentRow, currentCol).formatAsString();
                }

                // Did we miss any cells?
                int thisCol = (new CellReference(cellReference)).getCol();
                currentCol = thisCol;

                cellReference = cellReference.replaceAll("\\d","");
                rowValues.put(cellReference, formattedValue);

            }

            @Override
            public void headerFooter(String text, boolean isHeader, String tagName) {
            }
        };
    }

    /**
     * Parses and shows the content of one sheet using the specified styles and
     * shared-strings tables.
     *
     * @param styles
     * @param strings
     * @param sheetInputStream
     */
    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());
        }
    }
}

Answer 1

Excel显示和Apache POI读取的值的差异来自对用户语言设置有反应的日期格式。从Excel：

以星号（*）开头的日期格式会响应为操作系统指定的区域日期和时间设置的更改。

Apache POI DataFormatter会忽略这些特定于语言环境的格式，并返回默认的美国格式日期。从Apache POI DataFormatter文档中：

某些格式由Excel自动“本地化”，例如，在某些语言环境中加载到Excel中时，显示为mm / dd / yyyy，而在其他语言环境中则显示为dd / mm / yyyy。这些总是以“默认”（美国）格式返回，与存储在文件中一样。

要变通解决此问题，请参见Java: excel to csv date conversion issue with Apache Poi的答案