Convert csv to xls/xlsx using Apache poi? - spring

Question

I need to convert csv to xls/xlsx in my project? How can i do that? Can anyone post me some examples? I want to do it with Apache poi. I also need to create a cell from java side.

Answer 1

You can try following method to create xlsx file using apache-poi.
public static void csvToXLSX() {
try {
String csvFileAddress = "test.csv"; //csv file address
String xlsxFileAddress = "test.xlsx"; //xlsx file address
XSSFWorkbook workBook = new XSSFWorkbook();
XSSFSheet sheet = workBook.createSheet("sheet1");
String currentLine=null;
int RowNum=0;
BufferedReader br = new BufferedReader(new FileReader(csvFileAddress));
while ((currentLine = br.readLine()) != null) {
String str[] = currentLine.split(",");
RowNum++;
XSSFRow currentRow=sheet.createRow(RowNum);
for(int i=0;i<str.length;i++){
currentRow.createCell(i).setCellValue(str[i]);
}
}
FileOutputStream fileOutputStream = new FileOutputStream(xlsxFileAddress);
workBook.write(fileOutputStream);
fileOutputStream.close();
System.out.println("Done");
} catch (Exception ex) {
System.out.println(ex.getMessage()+"Exception in try");
}
}

Answer 2

We can use SXSSF Jar in which we can parse a long file as below:
public static void main( String[] args ) {
try {
// String fName = args[ 0 ];
String csvFileAddress = "C:\\Users\\psingh\\Desktop\\test\\New folder\\GenericDealerReport - version6.txt"; //csv file address
String xlsxFileAddress = "C:\\Users\\psingh\\Desktop\\trial\\test3.xlsx"; //xlsx file address
SXSSFWorkbook workBook = new SXSSFWorkbook( 1000 );
org.apache.poi.ss.usermodel.Sheet sheet = workBook.createSheet( "sheet1" );
String currentLine = null;
int RowNum = -1;
BufferedReader br = new BufferedReader( new FileReader( csvFileAddress ) );
while ( ( currentLine = br.readLine() ) != null ) {
String str[] = currentLine.split( "\\|" );
RowNum++;
Row currentRow = sheet.createRow( RowNum );
for ( int i = 0; i < str.length; i++ ) {
currentRow.createCell( i )
.setCellValue( str[ i ] );
}
}
DateFormat df = new SimpleDateFormat( "yyyy-mm-dd-HHmmss" );
Date today = Calendar.getInstance()
.getTime();
String reportDate = df.format( today );
FileOutputStream fileOutputStream = new FileOutputStream( xlsxFileAddress );
workBook.write( fileOutputStream );
fileOutputStream.close();
//System.out.println( "Done" );
}
catch ( Exception ex ) {
System.out.println( ex.getMessage() + "Exception in try" );
}
}

Answer 3

public static void convertCsvToXlsx(String xlsLocation, String csvLocation) throws Exception {
SXSSFWorkbook workbook = new SXSSFWorkbook();
SXSSFSheet sheet = workbook.createSheet("Sheet");
AtomicReference<Integer> row = new AtomicReference<>(0);
Files.readAllLines(Paths.get(csvLocation)).forEach(line -> {
Row currentRow = sheet.createRow(row.getAndSet(row.get() + 1));
String[] nextLine = line.split(",");
Stream.iterate(0, i -> i + 1).limit(nextLine.length).forEach(i -> {
currentRow.createCell(i).setCellValue(nextLine[i]);
});
});
FileOutputStream fos = new FileOutputStream(new File(xlsLocation));
workbook.write(fos);
fos.flush();
}

Answer 4

I have found SXSSFWorkbook really faster then XSSFWorkbook. Here is the modified code:
try {
String csvFileInput = "inputFile.csv";
String xlsxFileOutput ="outputFile.xls";
LOGGER.error(csvFileInput);
LOGGER.error( xlsxFileOutput);
SXSSFWorkbook workBook = new SXSSFWorkbook();
Sheet sheet = workBook.createSheet(transformBean.getOutputFileName());
String currentLine = null;
int RowNum = 0;
BufferedReader br = new BufferedReader(new FileReader(csvFileInput));
while ((currentLine = br.readLine()) != null) {
String str[] = currentLine.split(",");
RowNum++;
Row currentRow = sheet.createRow(RowNum);
for (int i = 0; i < str.length; i++) {
currentRow.createCell(i).setCellValue(str[i]);
}
}
FileOutputStream fileOutputStream = new FileOutputStream(xlsxFileOutput);
workBook.write(fileOutputStream);
fileOutputStream.close();
System.out.println("Done");
} catch (Exception ex) {
System.out.println(ex.getMessage() + "Found Exception");
}

Answer 5

if(new File(newFileName).isFile()) return;
#SuppressWarnings("resource")
HSSFWorkbook wb = new HSSFWorkbook();
Row xlsRow;
Cell xlsCell;
HSSFSheet sheet = wb.createSheet("sheet1");
int rowIndex = 0;
for(CSVRecord record : CSVFormat.EXCEL.parse(new FileReader(fileName))) {
xlsRow = sheet.createRow(rowIndex);
for(int i = 0; i < record.size(); i ++){
xlsCell = xlsRow.createCell(i);
xlsCell.setCellValue(record.get(i));
}
rowIndex ++;
}
FileOutputStream out = new FileOutputStream(newFileName);
wb.write(out);
out.close();

Answer 6

Try this one if you have inputstream
public static XSSFWorkbook csvToXLSX(InputStream inputStream) throws IOException {
XSSFWorkbook workBook = new XSSFWorkbook();
try(BufferedReader br = new BufferedReader(new InputStreamReader(inputStream))) {
Sheet sheet = workBook.createSheet("sheet1");
String currentLine=null;
int rowNum=0;
while ((currentLine = br.readLine()) != null) {
String[] str = currentLine.split(",");
rowNum++;
Row currentRow=sheet.createRow(rowNum);
for(int i=0;i<str.length;i++){
currentRow.createCell(i).setCellValue(str[i]);
}
}
log.info("CSV file converted to the workbook");
return workBook;
} catch (Exception ex) {
log.error("Exception while converting csv to xls {}",ex);
}finally {
if (Objects.nonNull(workBook)) {
workBook.close();
}
}
return workBook;
}