read .xlsx file and generate csv file

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintStream;

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.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,
    }

    int countrows = 0;

    /**
     * Derived from http://poi.apache.org/spreadsheet/how-to.html#xssf_sax_api
     * <p/>
     * Also see Standard ECMA-376, 1st edition, part 4, pages 1928ff, at
     * http://www.ecma-international.org/publications/standards/Ecma-376.htm
     * <p/>
     * A web-friendly version is http://openiso.org/Ecma/376/Part4
     */
    class MyXSSFSheetHandler extends DefaultHandler {

        /**
         * 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)
                            thisStr = formatter.formatRawCellContents(Double.parseDouble(n), this.formatIndex, this.formatString);
                        else
                            thisStr = n;
                        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();
                output.println(countrows++);
                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;

    /**
     * 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;
    }

    /**
     * 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();
            this.output.println();
            this.output.println(sheetName + " [index=" + index + "]:");
            processSheet(styles, strings, stream);
            stream.close();
            ++index;
        }
    }

    public static void main(String[] args) throws Exception {
        /* if (args.length < 1) {
            System.err.println("Use:");
            System.err.println("  XLSX2CSV <xlsx file> [min columns]");
            return;
        }*/

        //File xlsxFile = new File(args[0]);
        File xlsxFile = new File("input1.xlsx");
        if (!xlsxFile.exists()) {
            System.err.println("Not found or not a file: " + xlsxFile.getPath());
            return;
        }

        int minColumns = -1;
        //if (args.length >= 2)
        //minColumns = Integer.parseInt(args[1]);

        minColumns = 2;
        // The package open is instantaneous, as it should be.
        OPCPackage p = OPCPackage.open(xlsxFile.getPath(), PackageAccess.READ);
        XLSX2CSV xlsx2csv = new XLSX2CSV(p, System.out, minColumns);
        xlsx2csv.process();
    }

}
.

I am using above code to read contents of XLSX. I would like to extend it to create csv file out of the .xlsx content. How can I achieve it.
Any ideas, suggestions, sample code, links, source code highly appreciated. Thanks in advance
LVL 7
gudii9Asked:
Who is Participating?
 
SANTABABYCommented:
How about saving those XLSX files as CSV.
VBA macro can automate the above steps for eack worksheet in your workbook and even extend the functionality to process multiple workbook.
For more help, please provide details and attach example workbook.
0
 
gudii9Author Commented:
I cannot use VBA macro. i have to use java only sorry. Please advise
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.