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Converts Excel to CSV using usermodel.
git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@934444 13f79535-47bb-0310-9956-ffa450edef68
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Mark Beardsley
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commit
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/* ====================================================================
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==================================================================== */
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package org.apache.poi.ss.examples;
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import org.apache.poi.ss.usermodel.WorkbookFactory;
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import org.apache.poi.ss.usermodel.Workbook;
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import org.apache.poi.ss.usermodel.Sheet;
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import org.apache.poi.ss.usermodel.Row;
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import org.apache.poi.ss.usermodel.Cell;
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import org.apache.poi.ss.usermodel.DataFormatter;
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import org.apache.poi.ss.usermodel.FormulaEvaluator;
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import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
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import java.io.File;
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import java.io.FileInputStream;
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import java.io.FileWriter;
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import java.io.BufferedWriter;
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import java.io.FilenameFilter;
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import java.io.IOException;
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import java.io.FileNotFoundException;
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import java.util.ArrayList;
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/**
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* Demonstrates one way to convert an Excel spreadsheet into a CSV
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* file. This class makes the following assumptions;
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*
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* <list>
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* <li>1. Where the Excel workbook contains more that one worksheet, then a single
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* CSV file will contain the data from all of the worksheets.</li>
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* <li>2. The data matrix contained in the CSV file will be square. This means that
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* the number of fields in each record of the CSV file will match the number
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* of cells in the longest row found in the Excel workbook. Any short records
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* will be 'padded' with empty fields - an empty field is represented in the
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* the CSV file in this way - ,,.</li>
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* <li>3. Empty fields will represent missing cells.</li>
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* <li>4. A record consisting of empty fields will be used to represent an empty row
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* in the Excel workbook.</li>
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* </list>
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*
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* Therefore, if the worksheet looked like this;
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*
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* <pre>
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* ___________________________________________
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* | | | | | |
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* | A | B | C | D | E |
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* ___|_______|_______|_______|_______|_______|
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* | | | | | |
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* 1 | 1 | 2 | 3 | 4 | 5 |
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* ___|_______|_______|_______|_______|_______|
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* | | | | | |
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* 2 | | | | | |
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* ___|_______|_______|_______|_______|_______|
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* | | | | | |
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* 3 | | A | | B | |
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* ___|_______|_______|_______|_______|_______|
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* | | | | | |
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* 4 | | | | | Z |
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* ___|_______|_______|_______|_______|_______|
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* | | | | | |
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* 5 | 1,400 | | 250 | | |
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* ___|_______|_______|_______|_______|_______|
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*
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* </pre>
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*
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* Then, the resulting CSV file will contain the following lines (records);
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*
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* <pre>
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* 1,2,3,4,5
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* ,,,,
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* ,A,,B,
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* ,,,,Z
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* "1,400",,250,,
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* </pre>
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* <p>
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* Typically, the comma is used to separate each of the fields that, together,
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* constitute a single record or line within the CSV file. This is not however
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* a hard and fast rule and so this class allows the user to determine which
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* character is used as the field separator and assumes the comma if none other
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* is specified.
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* </p><p>
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* If a field contains the separator then it will be escaped. If the file should
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* obey Excel's CSV formatting rules, then the field will be surrounded with
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* speech marks whilst if it should obey UNIX conventions, each occurrence of
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* the separator will be preceded by the backslash character.
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* </p><p>
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* If a field contains an end of line (EOL) character then it too will be
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* escaped. If the file should obey Excel's CSV formatting rules then the field
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* will again be surrounded by speech marks. On the other hand, if the file
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* should follow UNIX conventions then a single backslash will precede the
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* EOL character. There is no single applicable standard for UNIX and some
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* appications replace the CR with \r and the LF with \n but this class will
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* not do so.
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* </p><p>
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* If the field contains double quotes then that character will be escaped. It
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* seems as though UNIX does not define a standard for this whilst Excel does.
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* Should the CSV file have to obey Excel's formmating rules then the speech
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* mark character will be escaped with a second set of speech marks. Finally, an
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* enclosing set of speah marks will also surround the entire field. Thus, if
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* the following line of text appeared in a cell - "Hello" he said - it would
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* look like this when converted into a field within a CSV file - """Hello"" he
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* said".
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* </p><p>
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* Finally, it is worth noting that talk of CSV 'standards' is really slightly
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* missleading as there is no such thing. It may well be that the code in this
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* class has to be modified to produce files to suit a specific application
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* or requirement.
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* </p>
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* @author Mark B [msb at apache.org]
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* @version 1.00 9th April 2010
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* 1.10 13th April 2010 - Added support for processing all Excel
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* workbooks in a folder along with the ability
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* to specify a field separator character.
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* 2.00 14th April 2010 - Added support for embedded characters; the
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* field separator, EOL and double quotes or
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* speech marks. In addition, gave the client
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* the ability to select how these are handled,
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* either obeying Excel's or UNIX formatting
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* conventions.
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*/
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public class ToCSV {
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private Workbook workbook = null;
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private ArrayList<ArrayList> csvData = null;
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private int maxRowWidth = 0;
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private int formattingConvention = 0;
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private DataFormatter formatter = null;
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private FormulaEvaluator evaluator = null;
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private String separator = null;
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private static final String CSV_FILE_EXTENSION = ".csv";
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private static final String DEFAULT_SEPARATOR = ",";
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/**
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* Identifies that the CSV file should obey Excel's formatting conventions
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* with regard to escaping certain embedded characters - the field separator,
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* speech mark and end of line (EOL) character
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*/
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public static final int EXCEL_STYLE_ESCAPING = 0;
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/**
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* Identifies that the CSV file should obey UNIX formatting conventions
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* with regard to escaping certain embedded characters - the field separator
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* and end of line (EOL) character
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*/
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public static final int UNIX_STYLE_ESCAPING = 1;
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/**
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* Process the contents of a folder, convert the contents of each Excel
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* workbook into CSV format and save the resulting file to the specified
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* folder using the same name as the original workbook with the .xls or
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* .xlsx extension replaced by .csv. This method will ensure that the
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* CSV file created contains the comma field separator and that embedded
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* characters such as the field separator, the EOL and double quotes are
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* escaped in accordance with Excel's convention.
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*
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* @param strSource An instance of the String class that encapsulates the
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* name of and path to either a folder containing those Excel
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* workbook(s) or the name of and path to an individual Excel workbook
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* that is/are to be converted.
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* @param strDestination An instance of the String class encapsulating the
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* name of and path to a folder that will contain the resulting CSV
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* files.
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* @throws java.io.FileNotFoundException Thrown if any file cannot be located
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* on the filesystem during processing.
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* @throws java.io.IOException Thrown if the filesystem encounters any
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* problems during processing.
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* @throws java.lang.IllegalArgumentException Thrown if the values passed
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* to the strSource parameter refers to a file or folder that does not
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* exist or if the value passed to the strDestination paramater refers
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* to a folder that does not exist or simply does not refer to a
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* folder.
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* @throws org.apache.poi.openxml4j.exceptions.InvalidFormatException Thrown
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* if the xml markup encountered whilst parsing a SpreadsheetML
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* file (.xlsx) is invalid.
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*/
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public void convertExcelToCSV(String strSource, String strDestination)
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throws FileNotFoundException, IOException,
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IllegalArgumentException, InvalidFormatException {
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// Simply chain the call to the overloaded convertExcelToCSV(String,
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// String, String, int) method, pass the default separator and ensure
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// that certain embedded characters are escaped in accordance with
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// Excel's formatting conventions
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this.convertExcelToCSV(strSource, strDestination,
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ToCSV.DEFAULT_SEPARATOR, ToCSV.EXCEL_STYLE_ESCAPING);
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}
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/**
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* Process the contents of a folder, convert the contents of each Excel
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* workbook into CSV format and save the resulting file to the specified
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* folder using the same name as the original workbook with the .xls or
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* .xlsx extension replaced by .csv. This method allows the client to
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* define the field separator but will ensure that embedded characters such
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* as the field separator, the EOL and double quotes are escaped in
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* accordance with Excel's convention.
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*
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* @param strSource An instance of the String class that encapsulates the
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* name of and path to either a folder containing those Excel
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* workbook(s) or the name of and path to an individual Excel workbook
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* that is/are to be converted.
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* @param strDestination An instance of the String class encapsulating the
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* name of and path to a folder that will contain the resulting CSV
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* files.
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* @param separator An instance of the String class that encapsulates the
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* character or characters the client wishes to use as the field
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* separator.
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* @throws java.io.FileNotFoundException Thrown if any file cannot be located
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* on the filesystem during processing.
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* @throws java.io.IOException Thrown if the filesystem encounters any
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* problems during processing.
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* @throws java.lang.IllegalArgumentException Thrown if the values passed
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* to the strSource parameter refers to a file or folder that does not
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* exist or if the value passed to the strDestination paramater refers
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* to a folder that does not exist or simply does not refer to a
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* folder.
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* @throws org.apache.poi.openxml4j.exceptions.InvalidFormatException Thrown
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* if the xml markup encounetered whilst parsing a SpreadsheetML
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* file (.xlsx) is invalid.
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*/
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public void convertExcelToCSV(String strSource, String strDestination,
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String separator)
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throws FileNotFoundException, IOException,
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IllegalArgumentException, InvalidFormatException {
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// Simply chain the call to the overloaded convertExcelToCSV(String,
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// String, String, int) method and ensure that certain embedded
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// characters are escaped in accordance with Excel's formatting
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// conventions
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this.convertExcelToCSV(strSource, strDestination,
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separator, ToCSV.EXCEL_STYLE_ESCAPING);
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}
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/**
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* Process the contents of a folder, convert the contents of each Excel
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* workbook into CSV format and save the resulting file to the specified
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* folder using the same name as the original workbook with the .xls or
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* .xlsx extension replaced by .csv
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*
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* @param strSource An instance of the String class that encapsulates the
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* name of and path to either a folder containing those Excel
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* workbook(s) or the name of and path to an individual Excel workbook
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* that is/are to be converted.
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* @param strDestination An instance of the String class encapsulating the name
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* of and path to a folder that will contain the resulting CSV files.
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* @param formattingConvention A primitive int whose value will determine
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* whether certain embedded characters should be escaped in accordance
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* with Excel's or UNIX formatting conventions. Two constants are
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* defined to support this option; ToCSV.EXCEL_STYLE_ESCAPING and
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* ToCSV.UNIX_STYLE_ESCAPING
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* @param separator An instance of the String class encapsulating the
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* characters or characters that should be used to separate items
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* on a line within the CSV file.
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* @throws java.io.FileNotFoundException Thrown if any file cannot be located
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* on the filesystem during processing.
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* @throws java.io.IOException Thrown if the filesystem encounters any
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* problems during processing.
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* @throws java.lang.IllegalArgumentException Thrown if the values passed
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* to the strSource parameter refers to a file or folder that does not
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* exist, if the value passed to the strDestination paramater refers
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* to a folder that does not exist, if the value passed to the
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* strDestination parameter does not refer to a folder or if the
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* value passed to the formattingConvention parameter is other than
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* one of the values defined by the constants ToCSV.EXCEL_STYLE_ESCAPING
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* and ToCSV.UNIX_STYLE_ESCAPING.
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* @throws org.apache.poi.openxml4j.exceptions.InvalidFormatException Thrown
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* if the xml markup encounetered whilst parsing a SpreadsheetML
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* file (.xlsx) is invalid.
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*/
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public void convertExcelToCSV(String strSource, String strDestination,
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String separator, int formattingConvention)
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throws FileNotFoundException, IOException,
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IllegalArgumentException, InvalidFormatException {
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File source = new File(strSource);
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File destination = new File(strDestination);
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File[] filesList = null;
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String destinationFilename = null;
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// Check that the source file/folder exists.
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if(!source.exists()) {
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throw new IllegalArgumentException("The source for the Excel " +
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"file(s) cannot be found.");
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}
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// Ensure thaat the folder the user has chosen to save the CSV files
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// away into firstly exists and secondly is a folder rather than, for
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// instance, a data file.
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if(!destination.exists()) {
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throw new IllegalArgumentException("The folder/directory for the " +
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"converted CSV file(s) does not exist.");
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}
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if(!destination.isDirectory()) {
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throw new IllegalArgumentException("The destination for the CSV " +
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"file(s) is not a directory/folder.");
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}
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// Ensure the value passed to the formattingConvention parameter is
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// within range.
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if(formattingConvention != ToCSV.EXCEL_STYLE_ESCAPING &&
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formattingConvention != ToCSV.UNIX_STYLE_ESCAPING) {
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throw new IllegalArgumentException("The value passed to the " +
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"formattingConvention parameter is out of range.");
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}
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// Copy the spearator character and formatting convention into local
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// variables for use in other methods.
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this.separator = separator;
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this.formattingConvention = formattingConvention;
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// Check to see if the sourceFolder variable holds a reference to
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// a file or a folder full of files.
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if(source.isDirectory()) {
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// Get a list of all of the Excel spreadsheet files (workbooks) in
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// the source folder/directory
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filesList = source.listFiles(new ExcelFilenameFilter());
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}
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else {
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// Assume that it must be a file handle - although there are other
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// options the code should perhaps check - and store the reference
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// into the filesList variable.
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filesList = new File[]{source};
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}
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// Step through each of the files in the source folder and for each
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// open the workbook, convert it's contents to CSV format and then
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// save the resulting file away into the folder specified by the
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// contents of the destination variable. Note that the name of the
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// csv file will be created by taking the name of the Excel file,
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// removing the extension and replacing it with .csv. Note that there
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// is one drawback with this approach; if the folder holding the files
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// contains two workbooks whose names match but one is a binary file
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// (.xls) and the other a SpreadsheetML file (.xlsx), then the names
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// for both CSV files will be identical and one CSV file will,
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// therefore, over-write the other.
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for(File excelFile : filesList) {
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// Open the workbook
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this.openWorkbook(excelFile);
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// Convert it's contents into a CSV file
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this.convertToCSV();
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// Build the name of the csv folder from that of the Excel workbook.
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// Simply replace the .xls or .xlsx file extension with .csv
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destinationFilename = excelFile.getName();
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destinationFilename = destinationFilename.substring(
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0, destinationFilename.lastIndexOf(".")) +
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ToCSV.CSV_FILE_EXTENSION;
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// Save the CSV file away using the newly constricted file name
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// and to the specified directory.
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this.saveCSVFile(new File(destination, destinationFilename));
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}
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}
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/**
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* Open an Excel workbook ready for conversion.
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*
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* @param file An instance of the File class that encapsulates a handle
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* to a valid Excel workbook. Note that the workbook can be in
|
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* either binary (.xls) or SpreadsheetML (.xlsx) format.
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* @throws java.io.FileNotFoundException Thrown if the file cannot be located.
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* @throws java.io.IOException Thrown if a problem occurs in the file system.
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* @throws org.apache.poi.openxml4j.exceptions.InvalidFormatException Thrown
|
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* if invalid xml is found whilst parsing an input SpreadsheetML
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* file.
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*/
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private void openWorkbook(File file) throws FileNotFoundException,
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IOException, InvalidFormatException {
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FileInputStream fis = null;
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try {
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System.out.println("Opening workbook [" + file.getName() + "]");
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fis = new FileInputStream(file);
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// Open the workbook and then create the FormulaEvaluator and
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// DataFormatter instances that will be needed to, respectively,
|
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// force evaluation of forumlae found in cells and create a
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// formatted String encapsulating the cells contents.
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this.workbook = WorkbookFactory.create(fis);
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this.evaluator = this.workbook.getCreationHelper().createFormulaEvaluator();
|
||||
this.formatter = new DataFormatter();
|
||||
}
|
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finally {
|
||||
if(fis != null) {
|
||||
fis.close();
|
||||
}
|
||||
}
|
||||
}
|
||||
|
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/**
|
||||
* Called to convert the contents of the currently opened workbook into
|
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* a CSV file.
|
||||
*/
|
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private void convertToCSV() {
|
||||
Sheet sheet = null;
|
||||
Row row = null;
|
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int lastRowNum = 0;
|
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this.csvData = new ArrayList<ArrayList>();
|
||||
|
||||
System.out.println("Converting files contents to CSV format.");
|
||||
|
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// Discover how many sheets there are in the workbook....
|
||||
int numSheets = this.workbook.getNumberOfSheets();
|
||||
|
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// and then iterate through them.
|
||||
for(int i = 0; i < numSheets; i++) {
|
||||
|
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// Get a reference to a sheet and check to see if it contains
|
||||
// any rows.
|
||||
sheet = this.workbook.getSheetAt(i);
|
||||
if(sheet.getPhysicalNumberOfRows() > 0) {
|
||||
|
||||
// Note down the index number of the bottom-most row and
|
||||
// then iterate through all of the rows on the sheet starting
|
||||
// from the very first row - number 1 - even if it is missing.
|
||||
// Recover a reference to the row and then call another method
|
||||
// which will strip the data from the cells and build lines
|
||||
// for inclusion in the resylting CSV file.
|
||||
lastRowNum = sheet.getLastRowNum();
|
||||
for(int j = 0; j <= lastRowNum; j++) {
|
||||
row = sheet.getRow(j);
|
||||
this.rowToCSV(row);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Called to actually save the data recovered from the Excel workbook
|
||||
* as a CSV file.
|
||||
*
|
||||
* @param file An instance of the File class that encapsulates a handle
|
||||
* referring to the CSV file.
|
||||
* @throws java.io.FileNotFoundException Thrown if the file cannot be found.
|
||||
* @throws java.io.IOException Thrown to indicate and error occurred in the
|
||||
* underylying file system.
|
||||
*/
|
||||
private void saveCSVFile(File file)
|
||||
throws FileNotFoundException, IOException {
|
||||
FileWriter fw = null;
|
||||
BufferedWriter bw = null;
|
||||
ArrayList<String> line = null;
|
||||
StringBuffer buffer = null;
|
||||
String csvLineElement = null;
|
||||
try {
|
||||
|
||||
System.out.println("Saving the CSV file [" + file.getName() + "]");
|
||||
|
||||
// Open a writer onto the CSV file.
|
||||
fw = new FileWriter(file);
|
||||
bw = new BufferedWriter(fw);
|
||||
|
||||
// Step through the elements of the ArrayList that was used to hold
|
||||
// all of the data recovered from the Excel workbooks' sheets, rows
|
||||
// and cells.
|
||||
for(int i = 0; i < this.csvData.size(); i++) {
|
||||
buffer = new StringBuffer();
|
||||
|
||||
// Get an element from the ArrayList that contains the data for
|
||||
// the workbook. This element will itself be an ArrayList
|
||||
// containing Strings and each String will hold the data recovered
|
||||
// from a single cell. The for() loop is used to recover elements
|
||||
// from this 'row' ArrayList one at a time and to write the Strings
|
||||
// away to a StringBuffer thus assembling a single line for inclusion
|
||||
// in the CSV file. If a row was empty or if it was short, then
|
||||
// the ArrayList that contains it's data will also be shorter than
|
||||
// some of the others. Therefore, it is necessary to check within
|
||||
// the for loop to ensure that the ArrayList contains data to be
|
||||
// processed. If it does, then an element will be recovered and
|
||||
// appended to the StringBuffer.
|
||||
line = this.csvData.get(i);
|
||||
for(int j = 0; j < this.maxRowWidth; j++) {
|
||||
if(line.size() > j) {
|
||||
csvLineElement = line.get(j);
|
||||
if(csvLineElement != null) {
|
||||
buffer.append(this.escapeEmbeddedCharacters(
|
||||
csvLineElement));
|
||||
}
|
||||
}
|
||||
if(j < (this.maxRowWidth - 1)) {
|
||||
buffer.append(this.separator);
|
||||
}
|
||||
}
|
||||
|
||||
// Once the line is built, write it away to the CSV file.
|
||||
bw.write(buffer.toString().trim());
|
||||
|
||||
// Condition the inclusion of new line characters so as to
|
||||
// avoid an additional, superfluous, new line at the end of
|
||||
// the file.
|
||||
if(i < (this.csvData.size() - 1)) {
|
||||
bw.newLine();
|
||||
}
|
||||
}
|
||||
}
|
||||
finally {
|
||||
if(bw != null) {
|
||||
bw.flush();
|
||||
bw.close();
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Called to convert a row of cells into a line of data that can later be
|
||||
* output to the CSV file.
|
||||
*
|
||||
* @param row An instance of either the HSSFRow or XSSFRow classes that
|
||||
* encapsulates information about a row of cells recovered from
|
||||
* an Excel workbook.
|
||||
*/
|
||||
private void rowToCSV(Row row) {
|
||||
Cell cell = null;
|
||||
int lastCellNum = 0;
|
||||
ArrayList<String> csvLine = new ArrayList<String>();
|
||||
|
||||
// Check to ensure that a row was recovered from the sheet as it is
|
||||
// possible that one or more rows between other populated rows could be
|
||||
// missing - blank. If the row does contain cells then...
|
||||
if(row != null) {
|
||||
|
||||
// Get the index for the right most cell on the row and then
|
||||
// step along the row from left to right recovering the contents
|
||||
// of each cell, converting that into a formatted String and
|
||||
// then storing the String into the csvLine ArrayList.
|
||||
lastCellNum = row.getLastCellNum();
|
||||
for(int i = 0; i <= lastCellNum; i++) {
|
||||
cell = row.getCell(i);
|
||||
if(cell == null) {
|
||||
csvLine.add("");
|
||||
}
|
||||
else {
|
||||
if(cell.getCellType() != Cell.CELL_TYPE_FORMULA) {
|
||||
csvLine.add(this.formatter.formatCellValue(cell));
|
||||
}
|
||||
else {
|
||||
csvLine.add(this.formatter.formatCellValue(cell, this.evaluator));
|
||||
}
|
||||
}
|
||||
}
|
||||
// Make a note of the index number of the right most cell. This value
|
||||
// will later be used to ensure that the matrix of data in the CSV file
|
||||
// is square.
|
||||
if(lastCellNum > this.maxRowWidth) {
|
||||
this.maxRowWidth = lastCellNum;
|
||||
}
|
||||
}
|
||||
this.csvData.add(csvLine);
|
||||
}
|
||||
|
||||
/**
|
||||
* Checks to see whether the field - which consists of the formatted
|
||||
* contents of an Excel worksheet cell encapsulated within a String - contains
|
||||
* any embedded characters that must be escaped. The method is able to
|
||||
* comply with either Excel's or UNIX formatting conventions in the
|
||||
* following manner;
|
||||
*
|
||||
* With regard to UNIX conventions, if the field contains any embedded
|
||||
* field separator or EOL characters they will each be escaped by prefixing
|
||||
* a leading backspace character. These are the only changes that have yet
|
||||
* emerged following some research as being required.
|
||||
*
|
||||
* Excel has other embedded character escaping requirements, some that emerged
|
||||
* from empirical testing, other through research. Firstly, with regards to
|
||||
* any embedded speech marks ("), each occurrence should be escaped with
|
||||
* another speech mark and the whole field then surrounded with speech marks.
|
||||
* Thus if a field holds <em>"Hello" he said</em> then it should be modified
|
||||
* to appear as <em>"""Hello"" he said"</em>. Furthermore, if the field
|
||||
* contains either embedded separator or EOL characters, it should also
|
||||
* be surrounded with speech marks. As a result <em>1,400</em> would become
|
||||
* <em>"1,400"</em> assuming that the comma is the required field separator.
|
||||
* This has one consequence in, if a field contains embedded speech marks
|
||||
* and embedded separator characters, checks for both are not required as the
|
||||
* additional set of speech marks that should be placed around ay field
|
||||
* containing embedded speech marks will also account for the embedded
|
||||
* separator.
|
||||
*
|
||||
* It is worth making one further note with regard to embedded EOL
|
||||
* characters. If the data in a worksheet is exported as a CSV file using
|
||||
* Excel itself, then the field will be surounded with speech marks. If the
|
||||
* resulting CSV file is then re-imports into another worksheet, the EOL
|
||||
* character will result in the original simgle field occupying more than
|
||||
* one cell. This same 'feature' is replicated in this classes behaviour.
|
||||
*
|
||||
* @param field An instance of the String class encapsulating the formatted
|
||||
* contents of a cell on an Excel worksheet.
|
||||
* @return A String that encapsulates the formatted contents of that
|
||||
* Excel worksheet cell but with any embedded separator, EOL or
|
||||
* speech mark characters correctly escaped.
|
||||
*/
|
||||
private String escapeEmbeddedCharacters(String field) {
|
||||
StringBuffer buffer = null;
|
||||
|
||||
// If the fields contents should be formatted to confrom with Excel's
|
||||
// convention....
|
||||
if(this.formattingConvention == ToCSV.EXCEL_STYLE_ESCAPING) {
|
||||
|
||||
// Firstly, check if there are any speech marks (") in the field. If
|
||||
// so, each occurrence must be escaped with another set of speahmarks
|
||||
// and then the entire field should be enclosed within another
|
||||
// set of speechmarks.
|
||||
if(field.contains("\"")) {
|
||||
buffer = new StringBuffer(field.replaceAll("\"", "\\\"\\\""));
|
||||
buffer.insert(0, "\"");
|
||||
buffer.append("\"");
|
||||
}
|
||||
else {
|
||||
// If the field contains either embedded separator or EOL
|
||||
// characters, then escape the whole field by surrounding it
|
||||
// with speech marks.
|
||||
buffer = new StringBuffer(field);
|
||||
if((buffer.indexOf(this.separator)) > -1 ||
|
||||
(buffer.indexOf("\n")) > -1) {
|
||||
buffer.insert(0, "\"");
|
||||
buffer.append("\"");
|
||||
}
|
||||
}
|
||||
return(buffer.toString().trim());
|
||||
}
|
||||
// The only other formatting convention this class obeys is the UNIX one
|
||||
// where any occurrence of the field separator or EOL character will
|
||||
// be escaped by preceding it with a backslash.
|
||||
else {
|
||||
if(field.contains(this.separator)) {
|
||||
field = field.replaceAll(this.separator, ("\\\\" + this.separator));
|
||||
}
|
||||
if(field.contains("\n")) {
|
||||
field = field.replaceAll("\n", "\\\\\n");
|
||||
}
|
||||
return(field);
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* The main() method contains code that demonstrates how to use the class.
|
||||
* @param args
|
||||
*/
|
||||
public static void main(String[] args) {
|
||||
// Check the number of arguments passed to the main method. There
|
||||
// must be two or three, the name of and path to either the folder
|
||||
// containing the Excel files or an individula Excel workbook that is/are
|
||||
// to be converted, the name of and path to the folder to which the CSV
|
||||
// files should be written and then finally, optionally, the separator
|
||||
// that should be used to separate individual items on the lines in the
|
||||
// CSV file. Note that the names of the CSV files will be derived from
|
||||
// those of the Excel file(s). Put simply the .xls or .xlsx extension
|
||||
// will be replaced with .csv.
|
||||
ToCSV converter = null;
|
||||
try {
|
||||
converter = new ToCSV();
|
||||
if(args.length == 2) {
|
||||
converter.convertExcelToCSV(args[0], args[1]);
|
||||
}
|
||||
else if(args.length == 3){
|
||||
converter.convertExcelToCSV(args[0], args[1], args[2]);
|
||||
}
|
||||
else if(args.length == 4) {
|
||||
converter.convertExcelToCSV(args[0], args[1],
|
||||
args[2], Integer.parseInt(args[3]));
|
||||
}
|
||||
else {
|
||||
System.out.println("Usage: java ToCSV \"Source Folder\" " +
|
||||
"\"Destination Folder\" \"CSV Element Separator\"");
|
||||
}
|
||||
}
|
||||
catch(Exception ex) {
|
||||
System.out.println("Caught an: " + ex.getClass().getName());
|
||||
System.out.println("Message: " + ex.getMessage());
|
||||
System.out.println("Stacktrace follows:.....");
|
||||
ex.printStackTrace(System.out);
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* An instance of this class can be used to control the files returned
|
||||
* be a call to the listFiles() method when made on an instance of the
|
||||
* File class and that object refers to a folder/directory
|
||||
*/
|
||||
class ExcelFilenameFilter implements FilenameFilter {
|
||||
|
||||
/**
|
||||
* Determine those files that will be returned by a call to the
|
||||
* listFiles() method. In this case, the name of the file must end with
|
||||
* either of the following two extension; '.xls' or '.xlsx'
|
||||
* @param file An instance of the File class that encapsulates a handle
|
||||
* referring to the folder/directory that contains the file.
|
||||
* @param name An instance of the String class that encapsulates the
|
||||
* name of the file.
|
||||
* @return A boolean value that indicates whether the file should be
|
||||
* included in the array retirned by the call to the listFiles()
|
||||
* method. In this case true will be returned if the name of the
|
||||
* file ends with either '.xls' or '.xlsx' and false will be
|
||||
* returned in all other instances.
|
||||
*/
|
||||
public boolean accept(File file, String name) {
|
||||
return(name.endsWith(".xls") || name.endsWith(".xlsx"));
|
||||
}
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue