POI EXCEL(.xls/.xlsx)转CSV格式

难点在于Date日期类型的转化，需要采用

//.xls:  
numrec.getXFIndex() == 62

//.xlsx:  
this.formatIndex == 31

判断日期类型，并结合 DateUtil.getJavaDate进行时间解析：

//.xls:  
new SimpleDateFormat("yyyy年MM月dd日").format(DateUtil.getJavaDate(numrec.getValue()));
//.xls:  
new SimpleDateFormat("yyyy年MM月dd日").format(DateUtil.getJavaDate(Double.parseDouble(n)));

.xls 转 csv

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintStream;
import java.text.SimpleDateFormat;
import java.util.ArrayList;

import org.apache.poi.hssf.eventusermodel.FormatTrackingHSSFListener;
import org.apache.poi.hssf.eventusermodel.HSSFEventFactory;
import org.apache.poi.hssf.eventusermodel.HSSFListener;
import org.apache.poi.hssf.eventusermodel.HSSFRequest;
import org.apache.poi.hssf.eventusermodel.MissingRecordAwareHSSFListener;
import org.apache.poi.hssf.eventusermodel.EventWorkbookBuilder.SheetRecordCollectingListener;
import org.apache.poi.hssf.eventusermodel.dummyrecord.LastCellOfRowDummyRecord;
import org.apache.poi.hssf.eventusermodel.dummyrecord.MissingCellDummyRecord;
import org.apache.poi.hssf.model.HSSFFormulaParser;
import org.apache.poi.hssf.record.BOFRecord;
import org.apache.poi.hssf.record.BlankRecord;
import org.apache.poi.hssf.record.BoolErrRecord;
import org.apache.poi.hssf.record.BoundSheetRecord;
import org.apache.poi.hssf.record.FormulaRecord;
import org.apache.poi.hssf.record.LabelRecord;
import org.apache.poi.hssf.record.LabelSSTRecord;
import org.apache.poi.hssf.record.NoteRecord;
import org.apache.poi.hssf.record.NumberRecord;
import org.apache.poi.hssf.record.RKRecord;
import org.apache.poi.hssf.record.Record;
import org.apache.poi.hssf.record.SSTRecord;
import org.apache.poi.hssf.record.StringRecord;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
import org.apache.poi.ss.usermodel.DateUtil;

public class XLS2CSV implements HSSFListener{

    private int minColumns;
    private POIFSFileSystem fs;
    private PrintStream output;

    private int lastRowNumber;
    private int lastColumnNumber;

    /** Should we output the formula, or the value it has? */
    private boolean outputFormulaValues = true;

    /** For parsing Formulas */
    private SheetRecordCollectingListener workbookBuildingListener;
    private HSSFWorkbook stubWorkbook;

    // Records we pick up as we process
    private SSTRecord sstRecord;
    private FormatTrackingHSSFListener formatListener;

    /** So we known which sheet we're on */
    private int sheetIndex = -1;
    private BoundSheetRecord[] orderedBSRs;
    private ArrayList boundSheetRecords = new ArrayList();

    // For handling formulas with string results
    private int nextRow;
    private int nextColumn;
    private boolean outputNextStringRecord;

    private final String OUTPUT_CHARSET = "GBK";

    private final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy年MM月dd日");


    /**
     * Creates a new XLS -> CSV converter
     *
     * @param fs
     *            The POIFSFileSystem to process
     * @param output
     *            The PrintStream to output the CSV to
     * @param minColumns
     *            The minimum number of columns to output, or -1 for no minimum
     */
    public XLS2CSV(POIFSFileSystem fs, PrintStream output, int minColumns) {
        this.fs = fs;
        this.output = output;
        this.minColumns = minColumns;
    }

    public XLS2CSV(String inputFilePath, String outputFilePath) throws Exception {
        fs = new POIFSFileSystem(new FileInputStream(inputFilePath));
        output = new PrintStream(outputFilePath, OUTPUT_CHARSET);
        minColumns = -1;
    }

    /**
     * Creates a new XLS -> CSV converter
     *
     * @param filename
     *            The file to process
     * @param minColumns
     *            The minimum number of columns to output, or -1 for no minimum
     * @throws IOException
     * @throws FileNotFoundException
     */
    public XLS2CSV(String filename, int minColumns) throws IOException,
            FileNotFoundException {
        this(new POIFSFileSystem(new FileInputStream(filename)), System.out,
                minColumns);
    }

    /**
     * Initiates the processing of the XLS file to CSV
     */
    public void process() throws IOException {
        MissingRecordAwareHSSFListener listener = new MissingRecordAwareHSSFListener(
                this);
        formatListener = new FormatTrackingHSSFListener(listener);

        HSSFEventFactory factory = new HSSFEventFactory();
        HSSFRequest request = new HSSFRequest();

        if (outputFormulaValues) {
            request.addListenerForAllRecords(formatListener);
        } else {
            workbookBuildingListener = new SheetRecordCollectingListener(
                    formatListener);
            request.addListenerForAllRecords(workbookBuildingListener);
        }

        factory.processWorkbookEvents(request, fs);
    }

    /**
     * Main HSSFListener method, processes events, and outputs the CSV as the
     * file is processed.
     */
    public void processRecord(Record record) {
        int thisRow = -1;
        int thisColumn = -1;
        String thisStr = null;
        //System.out.println(record.getSid());
        switch (record.getSid()) {
            case BoundSheetRecord.sid:
                //boundSheetRecords.add(record);
                break;
            case BOFRecord.sid:
                BOFRecord br = (BOFRecord) record;
                if (br.getType() == BOFRecord.TYPE_WORKSHEET) {
                    // Create sub workbook if required
                    if (workbookBuildingListener != null && stubWorkbook == null) {
                        stubWorkbook = workbookBuildingListener
                                .getStubHSSFWorkbook();
                    }

                    // Output the worksheet name
                    // Works by ordering the BSRs by the location of
                    // their BOFRecords, and then knowing that we
                    // process BOFRecords in byte offset order
                    sheetIndex++;
                    if (orderedBSRs == null) {
                        orderedBSRs = BoundSheetRecord
                                .orderByBofPosition(boundSheetRecords);
                    }
                    //output.println();
                    //不需要分页
                    //output.println(orderedBSRs[sheetIndex].getSheetname() + " ["
                    //     + (sheetIndex + 1) + "]:");
                }
                break;

            case SSTRecord.sid:
                sstRecord = (SSTRecord) record;
                break;

            case BlankRecord.sid:
                BlankRecord brec = (BlankRecord) record;

                thisRow = brec.getRow();
                thisColumn = brec.getColumn();
                thisStr = "";
                break;
            case BoolErrRecord.sid:
                BoolErrRecord berec = (BoolErrRecord) record;

                thisRow = berec.getRow();
                thisColumn = berec.getColumn();
                thisStr = "";
                break;

            case FormulaRecord.sid:
                FormulaRecord frec = (FormulaRecord) record;

                thisRow = frec.getRow();
                thisColumn = frec.getColumn();

                if (outputFormulaValues) {
                    if (Double.isNaN(frec.getValue())) {
                        // Formula result is a string
                        // This is stored in the next record
                        outputNextStringRecord = true;
                        nextRow = frec.getRow();
                        nextColumn = frec.getColumn();
                    } else {
                        thisStr = formatListener.formatNumberDateCell(frec);
                    }
                } else {
                    thisStr = '"' + HSSFFormulaParser.toFormulaString(stubWorkbook,
                            frec.getParsedExpression()) + '"';
                }
                break;
            case StringRecord.sid:
                if (outputNextStringRecord) {
                    // String for formula
                    StringRecord srec = (StringRecord) record;
                    thisStr = srec.getString();
                    thisRow = nextRow;
                    thisColumn = nextColumn;
                    outputNextStringRecord = false;
                }
                break;

            case LabelRecord.sid:
                LabelRecord lrec = (LabelRecord) record;

                thisRow = lrec.getRow();
                thisColumn = lrec.getColumn();
                thisStr = '"' + lrec.getValue() + '"';
                break;
            case LabelSSTRecord.sid:
                LabelSSTRecord lsrec = (LabelSSTRecord) record;

                thisRow = lsrec.getRow();
                thisColumn = lsrec.getColumn();
                if (sstRecord == null) {
                    thisStr = '"' + "(No SST Record, can't identify string)" + '"';
                } else {
                    thisStr = '"' + sstRecord.getString(lsrec.getSSTIndex())
                            .toString() + '"';
                }
                break;
            case NoteRecord.sid:
                NoteRecord nrec = (NoteRecord) record;

                thisRow = nrec.getRow();
                thisColumn = nrec.getColumn();
                // TODO: Find object to match nrec.getShapeId()
                thisStr = '"' + "(TODO)" + '"';
                break;
            case NumberRecord.sid:
                NumberRecord numrec = (NumberRecord) record;
                thisRow = numrec.getRow();
                thisColumn = numrec.getColumn();
                //if (DateUtil.isInternalDateFormat(numrec.getXFIndex())) {
                if (numrec.getXFIndex() == 62) {
                    thisStr = dateFormat.format(DateUtil.getJavaDate(numrec.getValue()));
                }else{
                    thisStr = formatListener.formatNumberDateCell(numrec);
                }
                //System.out.println("thisStr:  "+thisStr);
                break;
            case RKRecord.sid:
                RKRecord rkrec = (RKRecord) record;

                thisRow = rkrec.getRow();
                thisColumn = rkrec.getColumn();
                thisStr = '"' + "(TODO)" + '"';
                break;
            default:
                break;
        }

        // Handle new row
        if (thisRow != -1 && thisRow != lastRowNumber) {
            lastColumnNumber = -1;
        }

        // Handle missing column
        if (record instanceof MissingCellDummyRecord) {
            MissingCellDummyRecord mc = (MissingCellDummyRecord) record;
            thisRow = mc.getRow();
            thisColumn = mc.getColumn();
            thisStr = "";
        }

        // If we got something to print out, do so
        if (thisStr != null) {
            if (thisColumn > 0) {
                output.print(',');
            }
            output.print(thisStr);
        }

        // Update column and row count
        if (thisRow > -1)
            lastRowNumber = thisRow;
        if (thisColumn > -1)
            lastColumnNumber = thisColumn;

        // Handle end of row
        if (record instanceof LastCellOfRowDummyRecord) {
            // Print out any missing commas if needed
            if (minColumns > 0) {
                // Columns are 0 based
                if (lastColumnNumber == -1) {
                    lastColumnNumber = 0;
                }
                for (int i = lastColumnNumber; i < (minColumns); i++) {
                    output.print(',');
                }
            }

            // We're onto a new row
            lastColumnNumber = -1;

            // End the row
            output.println();
        }
    }

    public static void main(String[] args) throws Exception {
        XLS2CSV xls2csv = new XLS2CSV("D:\\a.xls","D:\\a.csv");
        xls2csv.process();
    }
}

.xlsx 转 csv

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintStream;
import java.text.SimpleDateFormat;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.apache.poi.openxml4j.exceptions.OpenXML4JException;
import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.openxml4j.opc.PackageAccess;
import org.apache.poi.ss.usermodel.BuiltinFormats;
import org.apache.poi.ss.usermodel.DataFormatter;
import org.apache.poi.ss.usermodel.DateUtil;
import org.apache.poi.xssf.eventusermodel.ReadOnlySharedStringsTable;
import org.apache.poi.xssf.eventusermodel.XSSFReader;
import org.apache.poi.xssf.model.StylesTable;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFRichTextString;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

public class XLSX2CSV {

    /**
     * The type of the data value is indicated by an attribute on the cell. The
     * value is usually in a "v" element within the cell.
     */
    enum xssfDataType {
        BOOL, ERROR, FORMULA, INLINESTR, SSTINDEX, NUMBER,
    }

    /**
     * Derived from http://poi.apache.org/spreadsheet/how-to.html#xssf_sax_api
     * 

     * Also see Standard ECMA-376, 1st edition, part 4, pages 1928ff, at
     * http://www.ecma-international.org/publications/standards/Ecma-376.htm
     * 

     * A web-friendly version is http://openiso.org/Ecma/376/Part4
     */
    class MyXSSFSheetHandler extends DefaultHandler {

        private final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy年MM月dd日");

        /**
         * Table with styles
         */
        private StylesTable stylesTable;

        /**
         * Table with unique strings
         */
        private ReadOnlySharedStringsTable sharedStringsTable;

        /**
         * Destination for data
         */
        private final PrintStream output;

        /**
         * Number of columns to read starting with leftmost
         */
        private final int minColumnCount;

        // Set when V start element is seen
        private boolean vIsOpen;

        // Set when cell start element is seen;
        // used when cell close element is seen.
        private xssfDataType nextDataType;

        // Used to format numeric cell values.
        private short formatIndex;
        private String formatString;
        private final DataFormatter formatter;

        private int thisColumn = -1;
        // The last column printed to the output stream
        private int lastColumnNumber = -1;

        // Gathers characters as they are seen.
        private StringBuffer value;

        /**
         * Accepts objects needed while parsing.
         *
         * @param styles
         *            Table of styles
         * @param strings
         *            Table of shared strings
         * @param cols
         *            Minimum number of columns to show
         * @param target
         *            Sink for output
         */
        public MyXSSFSheetHandler(StylesTable styles,
                                  ReadOnlySharedStringsTable strings, int cols, PrintStream target) {
            this.stylesTable = styles;
            this.sharedStringsTable = strings;
            this.minColumnCount = cols;
            this.output = target;
            this.value = new StringBuffer();
            this.nextDataType = xssfDataType.NUMBER;
            this.formatter = new DataFormatter();
        }

        /*
         * (non-Javadoc)
         *
         * @see
         * org.xml.sax.helpers.DefaultHandler#startElement(java.lang.String,
         * java.lang.String, java.lang.String, org.xml.sax.Attributes)
         */
        public void startElement(String uri, String localName, String name,
                                 Attributes attributes) throws SAXException {

            if ("inlineStr".equals(name) || "v".equals(name)) {
                vIsOpen = true;
                // Clear contents cache
                value.setLength(0);
            }
            // c => cell
            else if ("c".equals(name)) {
                // Get the cell reference
                String r = attributes.getValue("r");
                int firstDigit = -1;
                for (int c = 0; c < r.length(); ++c) {
                    if (Character.isDigit(r.charAt(c))) {
                        firstDigit = c;
                        break;
                    }
                }
                thisColumn = nameToColumn(r.substring(0, firstDigit));

                // Set up defaults.
                this.nextDataType = xssfDataType.NUMBER;
                this.formatIndex = -1;
                this.formatString = null;
                String cellType = attributes.getValue("t");
                String cellStyleStr = attributes.getValue("s");
                if ("b".equals(cellType))
                    nextDataType = xssfDataType.BOOL;
                else if ("e".equals(cellType))
                    nextDataType = xssfDataType.ERROR;
                else if ("inlineStr".equals(cellType))
                    nextDataType = xssfDataType.INLINESTR;
                else if ("s".equals(cellType))
                    nextDataType = xssfDataType.SSTINDEX;
                else if ("str".equals(cellType))
                    nextDataType = xssfDataType.FORMULA;
                else if (cellStyleStr != null) {
                    // It's a number, but almost certainly one
                    // with a special style or format
                    int styleIndex = Integer.parseInt(cellStyleStr);
                    XSSFCellStyle style = stylesTable.getStyleAt(styleIndex);
                    this.formatIndex = style.getDataFormat();
                    this.formatString = style.getDataFormatString();
                    if (this.formatString == null)
                        this.formatString = BuiltinFormats
                                .getBuiltinFormat(this.formatIndex);
                }
            }

        }

        /*
         * (non-Javadoc)
         *
         * @see org.xml.sax.helpers.DefaultHandler#endElement(java.lang.String,
         * java.lang.String, java.lang.String)
         */
        public void endElement(String uri, String localName, String name)
                throws SAXException {

            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);
                        thisStr = first == '0' ? "FALSE" : "TRUE";
                        break;

                    case ERROR:
                        thisStr = "\"ERROR:" + value.toString() + '"';
                        break;

                    case FORMULA:
                        // A formula could result in a string value,
                        // so always add double-quote characters.
                        thisStr = '"' + value.toString() + '"';
                        break;

                    case INLINESTR:
                        // TODO: have seen an example of this, so it's untested.
                        XSSFRichTextString rtsi = new XSSFRichTextString(value
                                .toString());
                        thisStr = '"' + rtsi.toString() + '"';
                        break;

                    case SSTINDEX:
                        String sstIndex = value.toString();
                        try {
                            int idx = Integer.parseInt(sstIndex);
                            XSSFRichTextString rtss = new XSSFRichTextString(
                                    sharedStringsTable.getEntryAt(idx));
                            thisStr = '"' + rtss.toString() + '"';
                        } catch (NumberFormatException ex) {
                            output.println("Failed to parse SST index '" + sstIndex
                                    + "': " + ex.toString());
                        }
                        break;

                    case NUMBER:
                        String n = value.toString();
                        if (this.formatString != null)
                            if(this.formatIndex == 31){
                                thisStr = dateFormat.format(DateUtil.getJavaDate(Double.parseDouble(n)));
                            }else{
                                thisStr = formatter.formatRawCellContents(Double
                                                .parseDouble(n), this.formatIndex,
                                        this.formatString);
                            }
                        else
                            thisStr = n;
                        //System.out.println("thisStr:  "+thisStr);
                        break;

                    default:
                        thisStr = "(TODO: Unexpected type: " + nextDataType + ")";
                        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;
                }
                for (int i = lastColumnNumber; i < thisColumn; ++i)
                    output.print(',');

                // Might be the empty string.
                output.print(thisStr);

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

            } else if ("row".equals(name)) {

                // Print out any missing commas if needed
                if (minColumns > 0) {
                    // Columns are 0 based
                    if (lastColumnNumber == -1) {
                        lastColumnNumber = 0;
                    }
                    for (int i = lastColumnNumber; i < (this.minColumnCount); i++) {
                        output.print(',');
                    }
                }

                // We're onto a new row
                output.println();
                lastColumnNumber = -1;
            }

        }

        /**
         * Captures characters only if a suitable element is open. Originally
         * was just "v"; extended for inlineStr also.
         */
        public void characters(char[] ch, int start, int length)
                throws SAXException {
            if (vIsOpen)
                value.append(ch, start, length);
        }

        /**
         * Converts an Excel column name like "C" to a zero-based index.
         *
         * @param name
         * @return Index corresponding to the specified name
         */
        private int nameToColumn(String name) {
            int column = -1;
            for (int i = 0; i < name.length(); ++i) {
                int c = name.charAt(i);
                column = (column + 1) * 26 + c - 'A';
            }
            return column;
        }

    }

    // /

    private OPCPackage xlsxPackage;
    private int minColumns;
    private PrintStream output;
    private final String OUTPUT_CHARSET = "GBK";

    /**
     * Creates a new XLSX -> CSV converter
     *
     * @param pkg
     *            The XLSX package to process
     * @param output
     *            The PrintStream to output the CSV to
     * @param minColumns
     *            The minimum number of columns to output, or -1 for no minimum
     */
    public XLSX2CSV(OPCPackage pkg, PrintStream output, int minColumns) {
        this.xlsxPackage = pkg;
        this.output = output;
        this.minColumns = minColumns;
    }

    //TODO catch exceptions
    public XLSX2CSV(String inputFilePath, String outputFilePath) throws Exception {
        xlsxPackage = OPCPackage.open(inputFilePath, PackageAccess.READ);
        output = new PrintStream(outputFilePath, OUTPUT_CHARSET);
        minColumns = -1;
    }

    /**
     * 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, InputStream sheetInputStream)
            throws IOException, ParserConfigurationException, SAXException {

        InputSource sheetSource = new InputSource(sheetInputStream);
        SAXParserFactory saxFactory = SAXParserFactory.newInstance();
        SAXParser saxParser = saxFactory.newSAXParser();
        XMLReader sheetParser = saxParser.getXMLReader();
        ContentHandler handler = new MyXSSFSheetHandler(styles, strings,
                this.minColumns, this.output);
        sheetParser.setContentHandler(handler);
        sheetParser.parse(sheetSource);
    }

    /**
     * Initiates the processing of the XLS workbook file to CSV.
     *
     * @throws IOException
     * @throws OpenXML4JException
     * @throws ParserConfigurationException
     * @throws SAXException
     */
    public void process() throws IOException, OpenXML4JException,
            ParserConfigurationException, SAXException {

        ReadOnlySharedStringsTable strings = new ReadOnlySharedStringsTable(
                this.xlsxPackage);
        XSSFReader xssfReader = new XSSFReader(this.xlsxPackage);
        StylesTable styles = xssfReader.getStylesTable();
        XSSFReader.SheetIterator iter = (XSSFReader.SheetIterator) xssfReader
                .getSheetsData();
        int index = 0;
        while (iter.hasNext()) {
            InputStream stream = iter.next();
            String sheetName = iter.getSheetName();
            //不要分页
            //this.output.println();
            //this.output.println(sheetName + " [index=" + index + "]:");
            processSheet(styles, strings, stream);
            stream.close();
            ++index;
        }
        close();
    }

    public void close(){
        this.output.close();
    }
    public static void main(String[] args) throws Exception {
        XLSX2CSV xlsx2csv = new XLSX2CSV("D:\\b.xlsx", "D:\\b.csv");
        xlsx2csv.process();
    }

}