Hi Mark
First of all I would like to thank you for all your explanation which you have
explained very well regarding the code. It was really helpful to understand the
flow of the code and I think its nice to have such audience and explanation
from an expert / one of the best, in the industry for a beginner like me.
I was executing your final Code to convert XLS into CSV. Its compiled, but
there was two messages ,
uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
I did google , for those messages and there was some directives , but as of
some forum says , it wont affect to the execution.
Finally , when I tried to execute it ,
java ToCSV d:\excel d:\csv ,
[java] Usage: java ToCSV "Source Folder" "Destination Folder" "CSV Element
Separator"
BUILD FAILED
Target "d:\excel" does not exist in the project "Inbox".
I tried to go through the code , if there is any thing that i can modified to
solve the problem.but no luck.
Thanks in advance
Luke
________________________________
From: MSB <markbrd...@tiscali.co.uk>
To: user@poi.apache.org
Sent: Tuesday, April 13, 2010 22:04:55
Subject: Re: Convert XLS into CSV
The code I have pasted into this message has been modified so that it is
possible to specify the path to and name of a folder containing one or more
Excel workbooks and the code will now iterate through each of the workbooks
in the folder and convert them into separate CSV files. The name of the
resulting CSV file will in each case be derived by taking the name of the
source Excel workbook, removing the .xls or xlsx extension and suffixing the
.csv extension. Before looking at the code in any detail - most of it is
identical by the way - I need to explain how you can call and use this
class. Forgive me if you know any of this but I thought it safer to assume
you might not be totally clear on the details.
When you run a Java class with a command like this;
java ToCSV
the runtime environment will locate the .class file, load and compile the
bytecode and then look inside the class for the main() method which, if that
method is present and it contains any code at all, is where execution of the
program will begin. If you look at the signature for the main() method, you
will see that it looks something like this;
public static void main(String[] args)
ignoring the public, static and void keywords for the moment, take a look at
what the brackets contain - String[] args. This is the declaration for a
variable called args which is able to hold a reference to an array where
each element of that array is an instance the java.lang.String class. This
array will hold any parameters that were specified on the command line when
the class was run. So, to modify the example above slightly, this;
java ToCSV C:/temp C:/temp/CSV
would result in a reference to an an array holding two Strings being passed
to the args parameter; the first element would hold "C:/temp" and the second
C:/temp/CSV. Well, more accurately, the elements would hold references to
instances of the String class that encapsulated the values "C:/temp" and
C:/temp/CSV.
The contents of the args parameter are accessible to any code within the
args method and so it is possible to extract the contents of the two
elements by simply referencing each using Java's standard notation; the
first element in the args array would be args[0] and the second args[1].
With this information, you can see how to run the ToCSV class from the
command line. All that you need do is specify the path to and name of either
an individual Excel workbook or of a folder that contains Excel workbook,
the path to and name of the folder that should contain the CSV files and,
optionally, the character or string of characters that will separate each
element on the line within the CSV file. The class can be invoked from the
command line in this manner;
java ToCSV "C:/temp/Excel Workbooks" "C:/temp/CSV Files"
or
java ToCSV C:/temp/Excel C:/temp/CSV ,
Note that the speach marks enclosing the paths in the first example are only
necessary if there are embedded spaces within the parameter.
If you now take a look at the code in the main() method of the ToCSV file,
you can see that it simply recovers the values from the args array and uses
them to call the convertExcelToCSV() method on an instance of the ToCSV
class.
Equally, you can call this class from code within another Java class. If you
choose to do this, it is an even simpler process; simply create an instance
of the ToCSV class and then call either of the overloaded
convertExcelToCSV() methods. One accepts two parameters, the name of and
path to the source Excel workbook(s) and the name of and path to the folder
the CSV files ought to be written to. If you call this method, it will be
assumed that the separtor is a comma. The other method accepts a third
parameter allowing you to define what the separator should be, so you could
pass a colon for example.
The process is a little like this;
ToCSV converter = new ToCSV();
converter.convertExcelToCSV("C:/temp/Excel Workbooks", "C:/temp/CSV Files",
"!");
The folder that contains the workbooks can hold other files as well, you do
not have to worry about copying the Excel workbooks to a special file for
processing. The ToCSV class is able to identify and select just Excel
workbook files that have extensions of '.xls' or '.xlsx' and it does this by
using an instance of an inner class called ExcelFilenameFilter that you can
see defined at the bottom of the source code, immediately following the
main() method. As you can see, it contains a single method - accept() - that
contains a single line of code. This line of code will return the boolean
value true if the name of a file ends with either '.xls' or '.xlsx' and an
instance of ExcelFilenameFilter can, therefore, be used, when the contents
of the folder are read, to ensure that only Excel workbooks are processed. I
often use inner classes like this if they are very small and simple or if
they only make sense in the context of the enclosing class. By this, I mean
asking yourslef if it is likely any other class may need similar
functionality.
Anayway, here is the code. Remember that it is only one possible solution
and you may need to modify how it works to suit your specific requirement.
You may not be worried, for example, if all of the rows in the CSV file
contain different numbers of elements. If this is the case, the contents of
the cells could be written out immediately after they were read and you
could completely remove the additional step of storing them in ArrayLists to
ensure the matrix is square.
package postprocessxlsx;
import org.apache.poi.ss.usermodel.WorkbookFactory;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.DataFormatter;
import org.apache.poi.ss.usermodel.FormulaEvaluator;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.BufferedWriter;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.util.ArrayList;
/**
* Demonstrate one way to convert an Excel spreadsheet into a CSV file. This
* class makes the following assumptions;
*
* 1. Where the Excel workbook contains more that one worksheet then a
single
* CSV file will contain the data from all of the worksheets.
* 2. The data matrix contained in the CSV file will be square. This means
that
* the number of elements in each row of the CSV file will match the
number
* of cells in the longest row found in the Excel workbook. Any short
rows
* will be 'padded' with empty elements - an empty elements is
represented in
* the CSV file in this way ,,.
* 3. Empty elements will represent missing cells.
* 4. A row consisting of empty elements will be used to represent an empty
row
* in the Excel workbook.
*
* @author Mark B
* @version 1.10 12th April 2010
*/
public class ToCSV {
private Workbook workbook = null;
private ArrayList<ArrayList> csvData = null;
private int maxRowWidth = 0;
private DataFormatter formatter = null;
private FormulaEvaluator evaluator = null;
private String separtor = null;
public static final String CSV_FILE_EXTENSION = ".csv";
public static final String DEFAULT_SEPARATOR = ",";
/**
* Process the contents of a folder, convert the contents of each Excel
* workbook into CSV format and save the resulting file to the specified
* folder using the same name as the original workbook with the .xls or
* .xlsx extension replaced by .csv
*
* @param source An instance of the String class that encapsulates the
* name of and path to either a folder containing those Excel
* workbook(s) or the name of and path to an individual Excel
workbook
* that is/are to be converted.
* @param destination An instance of the String class encapsulating the
name
* of and path to a folder that will contain the resulting CSV
files.
* @throws java.io.FileNotFoundException Thrown if any file cannot be
located
* on the filesystem during processing.
* @throws java.io.IOException Thrown if the filesystem encounters any
* problems during processing.
* @throws java.lang.IllegalArgumentException Thrown if the values
passed
* to the source parameters refers to a file or folder that does
not
* exist and if the value passed to the destination paramater
refers
* to a folder that does not exist or simply does not refer to a
* folder that does not exist.
* @throws org.apache.poi.openxml4j.exceptions.InvalidFormatException
Thrown
* if the xml markup encounetered whilst parsing a SpreadsheetML
* file (.xlsx) is invalid.
*/
public void convertExcelToCSV(String strSource, String strDestination)
throws FileNotFoundException, IOException,
IllegalArgumentException,
InvalidFormatException {
// Simply chain the call to the overloaded convertExcelToCSV(String,
// String, String) method and pass the default separator to ensure
this
// String is used to separate elemnts on the line in the CSV file.
this.convertExcelToCSV(strSource, strDestination,
ToCSV.DEFAULT_SEPARATOR);
}
/**
* Process the contents of a folder, convert the contents of each Excel
* workbook into CSV format and save the resulting file to the specified
* folder using the same name as the original workbook with the .xls or
* .xlsx extension replaced by .csv
*
* @param source An instance of the String class that encapsulates the
* name of and path to either a folder containing those Excel
* workbook(s) or the name of and path to an individual Excel
workbook
* that is/are to be converted.
* @param destination An instance of the String class encapsulating the
name
* of and path to a folder that will contain the resulting CSV
files.
* @param separator An instance of the String class encapsulating the
* characters or characters that should be used to separate items
* on a line within the CSV file.
* @throws java.io.FileNotFoundException Thrown if any file cannot be
located
* on the filesystem during processing.
* @throws java.io.IOException Thrown if the filesystem encounters any
* problems during processing.
* @throws java.lang.IllegalArgumentException Thrown if the values
passed
* to the source parameters refers to a file or folder that does
not
* exist and if the value passed to the destination paramater
refers
* to a folder that does not exist or simply does not refer to a
* folder that does not exist.
* @throws org.apache.poi.openxml4j.exceptions.InvalidFormatException
Thrown
* if the xml markup encounetered whilst parsing a SpreadsheetML
* file (.xlsx) is invalid.
*/
public void convertExcelToCSV(String strSource,
String strDestination, String separator)
throws FileNotFoundException, IOException,
IllegalArgumentException,
InvalidFormatException {
File source = new File(strSource);
File destination = new File(strDestination);
File[] filesList = null;
String destinationFilename = null;
// Check that the source file/folder exists.
if(!source.exists()) {
throw new IllegalArgumentException("The source for the Excel " +
"file(s) cannot be found.");
}
// Ensure thaat the folder the user has chosen to save the CSV files
// away into firstly exists and secondly is a folder rather than,
for
// instance, a data file.
if(!destination.exists()) {
throw new IllegalArgumentException("The folder/directory for the
" +
"converted CSV file(s) does not exist.");
}
if(!destination.isDirectory()) {
throw new IllegalArgumentException("The destination for the CSV
" +
"file(s) is not a directory/folder.");
}
// Check to see if the sourceFolder variable holds a reference to
// a file or a folder full of files.
if(source.isDirectory()) {
// Get a list of all of the Excel spreadsheet files (workbooks)
in
// the source folder/directory
filesList = source.listFiles(new ExcelFilenameFilter());
}
else {
// Assume that it must be a file handle - although there are
other
// options the code should perhaps check - and store the
reference
// into the filesList variable.
filesList = new File[]{source};
}
// Step through each of the files in the source folder and for each
// open the workbook, convert it's contents to CSV format and then
// save the resulting file away into the folder specified by the
// contents of the destination variable. Note that the name of the
// csv file will be created by taking the name of the Excel file,
// removing the extension and replacing it with .csv. Note that
there
// is one drawback with this approach; if the folder holding the
files
// contains two workbooks whose names match but one is a binary file
// (.xls) and the other a SpreadsheetML file (.xlsx), then the names
// for both CSV files will be identical and one CSV file will,
// therefore, over-write the other.
for(File excelFile : filesList) {
// Open the workbook
this.openWorkbook(excelFile);
// Convert it's contents into a CSV file
this.convertToCSV();
// Build the name of the csv folder from that of the Excel
workbook.
// Simply replace the .xls or .xlsx file extension with .csv
destinationFilename = excelFile.getName();
destinationFilename = destinationFilename.substring(
0, destinationFilename.lastIndexOf(".")) + ".csv";
// Save the CSV file away using the newly constricted file name
// and to the specified directory.
this.saveCSVFile(new File(destination, destinationFilename),
separator);
}
}
/**
* Open an Excel workbook ready for conversion.
*
* @param file An instance of the File class that encapsulates a handle
* to a valid Excel workbook. Note that the workbook can be in
* either binary (.xls) or SpreadsheetML (.xlsx) format.
*
* @throws java.io.FileNotFoundException Thrown if the file cannot be
located.
* @throws java.io.IOException Thrown if a problem occurs in the file
system.
* @throws org.apache.poi.openxml4j.exceptions.InvalidFormatException
Thrown
* if invalid xml is found whilst parsing an input SpreadsheetML
* file.
*/
private void openWorkbook(File file) throws FileNotFoundException,
IOException,
InvalidFormatException {
FileInputStream fis = null;
try {
System.out.println("Opening workbook [" + file.getName() + "]");
fis = new FileInputStream(file);
// Open the workbook and then create the FormulaEvaluator and
// DataFormatter instances that will be needed to, respectively,
// force evaluation of forumlae found in cells and create a
// formatted String encapsulating the cells contents.
this.workbook = WorkbookFactory.create(fis);
this.evaluator =
this.workbook.getCreationHelper().createFormulaEvaluator();
this.formatter = new DataFormatter();
}
finally {
if(fis != null) {
fis.close();
}
}
}
/**
* Called to convert the contents of the currently opened workbook into
* a CSV file.
*/
private void convertToCSV() {
Sheet sheet = null;
Row row = null;
int lastRowNum = 0;
this.csvData = new ArrayList<ArrayList>();
System.out.println("Converting files contents to CSV format.");
// Discover how many sheets there are in the workbook....
int numSheets = this.workbook.getNumberOfSheets();
// and then iterate through them.
for(int i = 0; i < numSheets; i++) {
// 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.
* @param separator An instance of the String class that encapsulates
the
* character or character that ought to be used to
delimit
* elements on the lines of 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, String separator)
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(csvLineElement);
}
}
if(j < (this.maxRowWidth - 1)) {
buffer.append(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.
*
* Note that no tests have yet been conducted with blank cells or those
* containing formulae. Such may require latereations to the way this
code
* works.
*
* @param row An instance of either the HSSFRow or XSSFRo 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);
}
/**
* 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 {
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"));
}
}
}
Luke_Devon wrote:
>
> Hi Mark
>
> I tested the code. It was fine. I could manage to convert XLS into CSV
> without any problem. But i have few more questions.
>
> In this code , you have been hard coded the path where XLS and CSV
> located. and file names also hard coded.
>
> How it would be pointing to a single directory and convert all XLS into
> CSV stored in the folder ?
>
> In the RAW XLS file , there might be some unwanted data to be converted
> into CSV. or some times we need to complete the blank cells in the excel
> sheet.
>
> How can we do it , before convert into CSV ?
>
> Sorry about all those simple questions.( Since I'm not a programmer)
>
> Thanks in advance
> Luke
>
>
>
>
>
> ________________________________
> From: MSB <markbrd...@tiscali.co.uk>
> To: user@poi.apache.org
> Sent: Friday, April 9, 2010 22:18:43
> Subject: Re: Convert XLS into CSV
>
>
> Hello Luke,
>
> As promised, a bit of code that uses the usermodel to create CSV files. I
> have not had the opportunity to test it thoroughly and do expect there to
> be
> issues so do not use the code in a production environment until you have
> put
> it through the wringer so to speak. Also, you may find the performance a
> little slower than you expect, especially if you are using the newer xml
> based file format and have run the eventusermodel code that Nick wrote.
>
> In essence, 'my' code simplt takes the contents of the workbook and
> converts
> it into an ArrayList of ArrayLists where each inner ArrayList contains
> zero,
> one or more Strings that describe the contents of a cell. I used this
> approach becuase it allows me to ensure that every row in the finished CVS
> file is the same length - with regard to the number of elements it
> contains
> - even if the input workbook contains rows that have varying numbers of
> cells on them. The code as it stands does evaluate any formulae that may
> be
> contained within cells and I hope will perform pretty much as you require.
> Take a look down into the main() method to see how it can be used; this
> method only shows the class being used to process a single file but an
> instance can be used to process more than one file in this manner;
>
> ToCSV converter = new ToCSV();
> converter.openWorkbook("C:/temp/To CSV.xls");
> converter.convertToCSV();
> converter.saveCSVFile("C:/temp/First CSV.csv", ";");
>
> converter.openWorkbook("C:/temp/Another To CSV.xlsx");
> converter.convertToCSV();
> converter.saveCSVFile("C:/temp/Second CSV.csv", ";");
>
>
> import org.apache.poi.ss.usermodel.WorkbookFactory;
> import org.apache.poi.ss.usermodel.Workbook;
> import org.apache.poi.ss.usermodel.Sheet;
> import org.apache.poi.ss.usermodel.Row;
> import org.apache.poi.ss.usermodel.Cell;
> import org.apache.poi.ss.usermodel.DataFormatter;
> import org.apache.poi.ss.usermodel.FormulaEvaluator;
> import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
>
> import java.io.File;
> import java.io.FileInputStream;
> import java.io.FileWriter;
> import java.io.BufferedWriter;
> import java.io.IOException;
> import java.io.FileNotFoundException;
> import java.util.ArrayList;
>
> /**
> * Demonstrate one way to convert an Excel spreadsheet into a CSV file.
> This
> * class makes the following assumptions;
> *
> * 1. Where the Excel workbook contains more that one worksheet then a
> single
> * CSV file will contain the data from all of the worksheets.
> * 2. The data matrix contained in the CSV file will be square. This means
> that
> * the number of elements in each row of the CSV file will match the
> number
> * of cells in the longest row found in the Excel workbook. Any short
> rows
> * will be 'padded' with empty elements - an empty elements is
> represented in
> * the CSV file in this way ,,.
> * 3. Empty elements will represent missing cells.
> * 4. A row consisting of empty elements will be used to represent an empty
> row
> * in the Excel workbook.
> *
> * @author Mark B
> * @version 1.00 9th April 2010
> */
> public class ToCSV {
>
> private Workbook workbook = null;
> private ArrayList<ArrayList> csvData = null;
> private int maxRowWidth = 0;
> private DataFormatter formatter = null;
> private FormulaEvaluator evaluator = null;
>
> /**
> * Open an Excel workbook readt for conversion.
> *
> * @param filename An instance of the String class that encapsulates
> the
> * path to and name of a valid Excel workbook. Note
> that
> the
> * workbook can be either a binary (.xls) or
> SpreadsheetML
> * (.xlsx) file.
> *
> * @throws java.io.FileNotFoundException Thrown if the file cannot be
> located.
> * @throws java.io.IOException Thrown if a problem occurs in the file
> system.
> * @throws org.apache.poi.openxml4j.exceptions.InvalidFormatException
> Thrown
> * if invalid xml is found whilst parsing an input SpreadsheetML
> file.
> */
> public void openWorkbook(String filename) throws
> FileNotFoundException,
> IOException,
> InvalidFormatException {
> File file = null;
> FileInputStream fis = null;
> try {
> file = new File(filename);
> fis = new FileInputStream(file);
> this.workbook = WorkbookFactory.create(fis);
> this.evaluator =
> this.workbook.getCreationHelper().createFormulaEvaluator();
> this.formatter = new DataFormatter();
> }
> finally {
> if(fis != null) {
> fis.close();
> }
> }
> }
>
> /**
> * Called to convert the contents of the currently opened workbook
> into
> * a CSV file.
> */
> public void convertToCSV() {
> Sheet sheet = null;
> Row row = null;
> int lastRowNum = 0;
> this.csvData = new ArrayList<ArrayList>();
>
> // Discover how many sheets there are in the workbook....
> int numSheets = this.workbook.getNumberOfSheets();
>
> // and then iterate through them.
> for(int i = 0; i < numSheets; i++) {
>
> // 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 filename An instance of the String class that encapsulates
> the
> * path to and name of the CSV file.
> * @param separator An instance of the String class that encapsulates
> the
> * character or character that ought to be used to
> delimit
> * elements on the lines of 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.
> */
> public void saveCSVFile(String filename, String separator)
> throws
> FileNotFoundException,
> IOException {
> File file = null;
> FileWriter fw = null;
> BufferedWriter bw = null;
> ArrayList<String> line = null;
> StringBuffer buffer = null;
> String csvLineElement = null;
> try {
> // Open a writer onto the CSV file.
> file = new File(filename);
> 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(csvLineElement);
> }
> }
> if(j < (this.maxRowWidth - 1)) {
> buffer.append(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.
> *
> * Note that no tests have yet been conducted with blank cells or
> those
> * containing formulae. Such may require latereations to the way this
> code
> * works.
> *
> * @param row An instance of either the HSSFRow or XSSFRo 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);
> }
>
> /**
> * The main() method contains code that demonstrates how to use the
> class.
> * @param args
> */
> public static void main(String[] args) {
> try {
> ToCSV converter = new ToCSV();
> converter.openWorkbook("C:/temp/To CSV.xls");
> converter.convertToCSV();
> converter.saveCSVFile("C:/temp/First CSV.csv", ";");
> }
> 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);
> }
>
> }
> }
>
> Test it out, have a good look through it and if there is anything you want
> to know just post to the list.
>
> Yours
>
> Mark B
>
>
> Luke_Devon wrote:
>>
>> Hi Mark,
>>
>> First of all I would like to thank you for the reply.
>>
>> Actually , currently I am using MS Office 2002. But I would like to use
>> the code for other latest versions also.
>> In my case , I dont want to do any validations for the EXCEL file ,
>> because I just wanted convert entire excel file into CSV.
>> Is there any simple java code available for such a basic requirement ?
>>
>> anyway I'll try to use the code in the link which you have given to me .
>>
>> Thanks & Regards
>>
>> Luke.
>>
>>
>>
>>
>> ________________________________
>> From: MSB <markbrd...@tiscali.co.uk>
>> To: user@poi.apache.org
>> Sent: Thursday, April 8, 2010 23:47:07
>> Subject: Re: Convert XLS into CSV
>>
>>
>> Hello Luke,
>>
>> Which version of the Excel file format are you targetting, the older
>> binary
>> or newer xml based version? I ask because Nick wrote and contributed some
>> code that can be used to convert the older binary files into csv. It uses
>> the eventmodel and will seem quite complex on first acquaintance but here
>> it
>> is;
>>
>> http://svn.apache.org/repos/asf/poi/trunk/src/examples/src/org/apache/poi/hssf/eventusermodel/examples/XLS2CSVmra.java
>>
>> I know that other users have modified the code to, for example, output
>> diffenert worksheets to separate csv files.
>>
>> Yours
>>
>> Mark B
>>
>>
>> Luke_Devon wrote:
>>>
>>> Hi
>>>
>>> I wanted to convert some XLS files into CSV. I found that apache.poi is
>>> the most perfect tool. Since I'm a beginner , i have no idea how to do
>>> that . Can some body help me please ? Do you have sample code for
>>> convert
>>> xls into csv ?
>>>
>>> Thanks in Advance
>>> Luke
>>>
>>>
>>>
>>> Get your preferred Email name!
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>>
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>>
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