Java tutorial
/*---------------------------------------------------------------------------------------------- * Copyright 2014 Federal IT Steering Unit FITSU Licensed under the Apache License, Version 2.0 (the "License"); you * may not use this file except in compliance with the License. You may obtain a copy of the License at * http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, * either express or implied. See the License for the specific language governing permissions and limitations under * the License. * * Contributors: * Marcel Bernet, Zurich - initial implementation *---------------------------------------------------------------------------------------------*/ package ch.admin.searchreplace; import java.io.File; 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; /** * A rudimentary XLSX -> CSV processor modeled on the POI sample program XLS2CSVmra by Nick Burch from the package * org.apache.poi.hssf.eventusermodel.examples. Unlike the HSSF version, this one completely ignores missing rows. * <p/> * Data sheets are read using a SAX parser to keep the memory footprint relatively small, so this should be able to * read enormous workbooks. The styles table and the shared-string table must be kept in memory. The standard POI * styles table class is used, but a custom (read-only) class is used for the shared string table because the * standard POI SharedStringsTable grows very quickly with the number of unique strings. * <p/> * Thanks to Eric Smith for a patch that fixes a problem triggered by cells with multiple "t" elements, which is how * Excel represents different formats (e.g., one word plain and one word bold). * * @author Chris Lott */ 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 * <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(); 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; break; } } 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]); 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]); // 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(); } }