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How to read from merged cells of Excel in Java using Apache POI?

I have a Excel file in .xlsx format. I have stored data by merging cells to form various columns. I am reading the Excel file via a Java web application and saving its data to a database (MySQL). But when I read from merged cells I get null values along with what are stored in the columns as well as the headers. I am using Apache POI. My code is:
public static void excelToDBLogIN() {
FileInputStream file = null;
Boolean flag = true;
ArrayList<String> rows = new ArrayList<String>();
try {
// here uploadFolder contains the path to the Login 3.xlsx file
file = new FileInputStream(new File(uploadFolder + "Login 3.xlsx"));
//Create Workbook instance holding reference to .xlsx file
XSSFWorkbook workbook = new XSSFWorkbook(file);
//Get first/desired sheet from the workbook
XSSFSheet sheet = workbook.getSheetAt(0);
//Iterate through each rows one by one
Iterator<Row> rowIterator = sheet.iterator();
while (rowIterator.hasNext()) {
Row row = rowIterator.next();
//For each row, iterate through all the columns
Iterator<Cell> cellIterator = row.cellIterator();
String tuple = "";
while (cellIterator.hasNext()) {
Cell cell = cellIterator.next();
//Check the cell type and format accordingly
switch (cell.getCellType()) {
case Cell.CELL_TYPE_NUMERIC:
//int value = new BigDecimal(cell.getNumericCellValue()).setScale(0, RoundingMode.HALF_UP).intValue();
//tuple = tuple + String.valueOf(value) + "+";
DataFormatter objDefaultFormat = new DataFormatter();
String str = objDefaultFormat.formatCellValue(cell);
tuple = tuple + str + "+";
break;
case Cell.CELL_TYPE_STRING:
tuple = tuple + cell.getStringCellValue() + "+";
break;
case Cell.CELL_TYPE_BLANK:
tuple = tuple + "" + "+";
break;
}
}
rows.add(tuple);
flag = true;
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (file != null) {
try {
file.close();
file = null;
} catch (Exception e) {
System.out.println("File closing operation failed");
e.printStackTrace();
}
}
}
}
}
I searched for answers in the web but did not find anything relevant.

Following code of snippet might help.
while (rowIterator.hasNext()) {
Row row = rowIterator.next();
//For each row, iterate through all the columns
Iterator<Cell> cellIterator = row.cellIterator();
outer:
while (cellIterator.hasNext()) {
Cell cell = cellIterator.next();
//will iterate over the Merged cells
for (int i = 0; i < sheet.getNumMergedRegions(); i++) {
CellRangeAddress region = sheet.getMergedRegion(i); //Region of merged cells
int colIndex = region.getFirstColumn(); //number of columns merged
int rowNum = region.getFirstRow(); //number of rows merged
//check first cell of the region
if (rowNum == cell.getRowIndex() && colIndex == cell.getColumnIndex()) {
System.out.println(sheet.getRow(rowNum).getCell(colIndex).getStringCellValue());
continue outer;
}
}
//the data in merge cells is always present on the first cell. All other cells(in merged region) are considered blank
if (cell.getCellType() == Cell.CELL_TYPE_BLANK || cell == null) {
continue;
}
System.out.println(cell.getStringCellValue());
}
}

This method can read a specific cell (including merged cell):
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import org.apache.poi.ss.usermodel.DateUtil;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public static void readCell(String excelFilePath, int rowIndex, int columnIndex) throws FileNotFoundException, IOException {
try (InputStream inp = new FileInputStream(excelFilePath)) {
XSSFWorkbook wb = new XSSFWorkbook(inp);
XSSFCell cell = wb.getSheetAt(0).getRow(rowIndex).getCell(columnIndex);
switch (cell.getCellType()) {
case STRING:
System.out.println(cell.getRichStringCellValue().getString());
break;
case NUMERIC:
if (DateUtil.isCellDateFormatted(cell)) {
System.out.println(cell.getDateCellValue());
} else {
System.out.println(cell.getNumericCellValue());
}
break;
case BOOLEAN:
System.out.println(cell.getBooleanCellValue());
break;
case FORMULA:
System.out.println(cell.getCellFormula());
break;
case BLANK:
System.out.println();
break;
default:
System.out.println();
}
wb.close();
}
}
Dependencies: POI 5.0.0, JDK 1.8.0

Convert .xls to .csv in Java

I want to convert the xls file to csv. I successfully converted it to a csv file, but the last column also has a comma appended. How do I remove the last comma, example 1,2,2,3,... Could you please help out?
package bwtest;
import java.io.*;
import java.util.Iterator;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
class ExcelToCSV {
static void convertToXlsx(File inputFile, File outputFile) {
// For storing data into CSV files
StringBuffer cellValue = new StringBuffer();
try {
FileOutputStream fos = new FileOutputStream(outputFile);
// Get the workbook instance for XLSX file
XSSFWorkbook wb = new XSSFWorkbook(new FileInputStream(inputFile));
// Get first sheet from the workbook
XSSFSheet sheet = wb.getSheetAt(0);
Row row;
Cell cell;
// Iterate through each rows from first sheet
Iterator<Row> rowIterator = sheet.iterator();
while (rowIterator.hasNext()) {
row = rowIterator.next();
// For each row, iterate through each columns
Iterator<Cell> cellIterator = row.cellIterator();
while (cellIterator.hasNext()) {
cell = cellIterator.next();
switch (cell.getCellType()) {
case Cell.CELL_TYPE_BOOLEAN:
cellValue.append(cell.getBooleanCellValue() + ",");
break;
case Cell.CELL_TYPE_NUMERIC:
cellValue.append(cell.getNumericCellValue()
+ ",");
break;
case Cell.CELL_TYPE_STRING:
cellValue.append(cell.getStringCellValue() + ",");
break;
case Cell.CELL_TYPE_BLANK:
cellValue.append("" + ",");
break;
default:
cellValue.append(cell + ",");
}
}
}
fos.write(cellValue.toString().getBytes());
fos.close();
} catch (Exception e) {
System.err.println("Exception :" + e.getMessage());
}
}
static void convertToXls(File inputFile, File outputFile) {
// For storing data into CSV files
StringBuffer cellDData = new StringBuffer();
try {
FileOutputStream fos = new FileOutputStream(outputFile);
// Get the workbook instance for XLS file
HSSFWorkbook workbook = new HSSFWorkbook(new FileInputStream(
inputFile));
// Get first sheet from the workbook
HSSFSheet sheet = workbook.getSheetAt(0);
Cell cell;
Row row;
// Iterate through each rows from first sheet
Iterator<Row> rowIterator = sheet.iterator();
while (rowIterator.hasNext()) {
row = rowIterator.next();
// For each row, iterate through each columns
Iterator<Cell> cellIterator = row.cellIterator();
while (cellIterator.hasNext()) {
cell = cellIterator.next();
switch (cell.getCellType()) {
case Cell.CELL_TYPE_BOOLEAN:
cellDData.append(cell.getBooleanCellValue() + ",");
break;
case Cell.CELL_TYPE_NUMERIC:
cellDData.append(cell.getNumericCellValue() + ",");
break;
case Cell.CELL_TYPE_STRING:
cellDData.append(cell.getStringCellValue() + ",");
break;
case Cell.CELL_TYPE_BLANK:
cellDData.append("" + ",");
break;
default:
cellDData.append(cell + ",");
}
}
}
fos.write(cellDData.toString().getBytes());
fos.close();
} catch (FileNotFoundException e) {
System.err.println("Exception" + e.getMessage());
} catch (IOException e) {
System.err.println("Exception" + e.getMessage());
}
}
public static void main(String[] args)
{
File inputFile = new File("C:\input.xls");
File outputFile = new File("C:\output1.csv");
File inputFile2 = new File("C:\input.xlsx");
File outputFile2 = new File("C:\output2.csv");
convertToXls(inputFile, outputFile);
convertToXlsx(inputFile2, outputFile2);
}
}

Assuming every row has cells:
After your cellIterator loop and before you rowIterator loop finishes, add:
cellDData.deleteCharAt(cellDData.length()-1);
This should delete the last comma in the line.
If it's possible to have a row where the cellIterator doesn't run(which I doubt) then you can put boolean hasCells = false; before the cellIterator loop, and set hasCells = true; inside of the loop somewhere. Then, only delete the comma if(hasCells)

Your conversion algorithm is incorrect.
Instead of adding value then comma,
you should add comma (if needed) then value.
Here is some code:
...
int columnNumber = 1;
while (cellIterator.hasNext())
{
if (columnNumber > 1)
{
cellValue.append(",")
}
row = rowIterator.next();
switch (cell.getCellType())
{
... append the cell value to the cellValue.
}
++columnNumber;
}
...

After each row you will need to insert a line feed "/r/n" and remove the last coma.
You can write it to the fos at that time.
if (cellDData != null && cellDData.length() > 1) {
String cellDDataString = cellDData.toString();
cellDDataString = cellDDataString.substring(0,cellDDataString.length() - 1) + "/r/n";
fos.write(cellDDataString);
}
cellDData = new StringBuffer();

excel file reading row wise values

im developing one tool for uploading excel and validate it, but excel file is large and the row count is about 65536.
here is my code used for uploading and reading the excel sheet values
int firstColNo = 1;
int rowcount = sheet.getRows();
int colCount = sheet.getColumns();
int row = 0;
String comp = "";
for (row = 1; row < rowcount; row++) {
if (labelCell != null) {
cell = sheet.getCell(firstColNo, row);
if (cell.getContents() != null && cell.getContents().length() > 0){
String compoundId = cell.getContents();
System.out.println(compoundId);
} else {
System.out.println("-");
}
}
}
by reading the row values it takes more to time to read, is there any way to make it faster else any code modifications need to be done in my code?
can anybody help me to overcome this issue.

Here is an example for you
HSSFWorkbook workbook = new HSSFWorkbook(file);
//Get first sheet from the workbook
HSSFSheet sheet = workbook.getSheetAt(0);
//Iterate through each rows from first sheet
Iterator<Row> rowIterator = sheet.iterator();
while(rowIterator.hasNext()) {
Row row = rowIterator.next();
//For each row, iterate through each columns
Iterator<Cell> cellIterator = row.cellIterator();
while(cellIterator.hasNext()) {
Cell cell = cellIterator.next();
switch(cell.getCellType()) {
case Cell.CELL_TYPE_BOOLEAN:
System.out.print(cell.getBooleanCellValue() + "\t\t");
break;
case Cell.CELL_TYPE_NUMERIC:
System.out.print(cell.getNumericCellValue() + "\t\t");
break;
case Cell.CELL_TYPE_STRING:
System.out.print(cell.getStringCellValue() + "\t\t");
break;
}
}
System.out.println("");
}

Checking for an empty cell in excel using JExcel API

How do I check if a CELL in excel sheet is empty and doesn't have any content inside it? I am traversing a row from left to right, and want to stop when I encounter an empty cell. I am using
cell.getType()==CellType.EMPTY
but it doesn't seem to work. Also,
if(cell.getContents() == "") is also not working.
What is the condition to check if the cell is a blank cell?
Thanks
Abhishek S

List cellDataList = new ArrayList();
XSSFWorkbook workbook = new XSSFWorkbook(fileInputStream);
XSSFSheet sheet = workbook.getSheetAt(0);
Iterator rows = sheet.rowIterator();
int number=sheet.getLastRowNum();
int lineNumber = 0;
while (rows.hasNext())
{
XSSFRow row = ((XSSFRow) rows.next());
lineNumber++;
if(lineNumber==1){continue;}
Iterator cells = row.cellIterator();
List cellTempList = new ArrayList();
int current = 0, next =1;
while(cells.hasNext())
{
XSSFCell cell = (XSSFCell) cells.next();
current = cell.getColumnIndex();
if(current<next){
}
else{
int loop = current-next;
for(int k=0;k<loop+1;k++){
cellTempList.add(null);
next = next + 1;
}
}
switch (cell.getCellType()) {
case Cell.CELL_TYPE_STRING:
System.out.println(cell.getRichStringCellValue().getString());
cellTempList.add(cell.getRichStringCellValue().getString());
break;
case Cell.CELL_TYPE_NUMERIC:
System.out.println(cell.getNumericCellValue());
cellTempList.add(String.valueOf(cell.getNumericCellValue()));
break;
case Cell.CELL_TYPE_BOOLEAN:
System.out.println(cell.getBooleanCellValue());
break;
case Cell.CELL_TYPE_FORMULA:
System.out.println(cell.getCellFormula());
cellTempList.add(cell.getCellFormula());
break;
default:
System.out.println("Inside default");
}
next = next + 1;
}
cellDataList.add(cellTempList);
}

String contents = cell.getContents();
if (contents != null && contents.length() != 0)

From the following link JExcel API, check cell.isEmpty() method to test.

How to get an Excel Blank Cell Value in Apache POI?

I have a huge excel file with tons of columns which looks like this :-
Column1 Column2 Column3 Column4 Column5
abc def ghi
mno pqr
......
This is the code that I wrote to print these values:
try {
FileInputStream inputStr = new FileInputStream(fileName);
XSSFWorkbook xssfWork = new XSSFWorkbook(inputStr) ;
XSSFSheet sheet1 = xssfWork.getSheetAt(0);
Iterator rowItr = sheet1.rowIterator();
while ( rowItr.hasNext() ) {
XSSFRow row = (XSSFRow) rowItr.next();
System.out.println("ROW:-->");
Iterator cellItr = row.cellIterator();
while ( cellItr.hasNext() ) {
XSSFCell cell = (XSSFCell) cellItr.next();
System.out.println("CELL:-->"+cell.toString());
}
}
} catch (Exception e) {
e.printStackTrace();
}
The output generated by this code is :-
ROW:-->
CELL:-->Column1
CELL:-->Column2
CELL:-->Column3
CELL:-->Column4
CELL:-->Column5
ROW:-->
CELL:-->abc
CELL:-->def
CELL:-->ghi
ROW:-->
CELL:-->mno
CELL:-->pqr
So, If we look at the output above we can note that the cells where I left blank values was not picked up by the POI library , is there a way in which I can get these values as null. or a way to recognize that the values presented skipped blank cells?
Thanks.

If you want to get all cells, no matter if they exist or not, then the iterator isn't for you. Instead, you need to manually fetch the appropriate cells, likely with a missing cell policy
for(Row row : sheet) {
for(int cn=0; cn<row.getLastCellNum(); cn++) {
// If the cell is missing from the file, generate a blank one
// (Works by specifying a MissingCellPolicy)
Cell cell = row.getCell(cn, Row.MissingCellPolicy.CREATE_NULL_AS_BLANK);
// Print the cell for debugging
System.out.println("CELL: " + cn + " --> " + cell.toString());
}
}
There's more details on all of this in the Apache POI documentation on iterating over cells

I have been frustrated by this same problem. Here is what I found with poi-3.7-20101029 and poi-3.8.
RowIterator and CellIterator do not support iterating over NULL cells or rows -- only physically defined cells (which can be BLANK).
The solution that returns what I expect requires using the 0-based Row.getCell([int], Row.CREATE_NULL_AS_BLANK), much like Chavira's answer alludes to (assuming 8 cell rows). Or you can use the Cell.columnIndex value while iterating to check for jumping numbers...
Annoyingly, after creating blank cells using method #1, the iterators will return the now created BLANK cells. I consider it a bug that MissingCellPolicy is ignored by CellIterator.

The reason is quite simple: Excel files can contain as many rows and as many columns as possibles, so returning all available blank rows and columns will render the cells huge and memory intensive.
Assuming you have a 10x10 sheet, in Excel, it's not "exactly" 10x10 since you can add 11x10 very easily with blank cell, so should POI return the 11th column?
One way to do what you're requesting is to use HSSFCell.getColumnIndex().
Example:
//Assuming your have a 2 dimensional array.
String[][] values = ......;// It is assigned
POIFSFileSystem fileSystem = new POIFSFileSystem(new FileInputStream(fileName));
HSSFWorkbook workbook = new HSSFWorkbook(fileSystem);
//Going through every worksheet.
for (int sheetPos = 0; sheetPos < workbook.getNumberOfSheets(); sheetPos++) {
HSSFSheet sheet = workbook.getSheetAt(sheetPos);
int rowPos = 0;
Iterator<Row> rows = sheet.rowIterator();
while (rows.hasNext()) {
HSSFRow row = (HSSFRow) rows.next();
Iterator<Cell> cells = row.cellIterator();
while (cells.hasNext()) {
HSSFCell cell = (HSSFCell) cells.next();
String value = "";
switch (cell.getCellType()) {
case HSSFCell.CELL_TYPE_NUMERIC:
value = BigDecimal.valueOf(cell.getNumericCellValue()).toPlainString();
break;
case HSSFCell.CELL_TYPE_STRING:
value = cell.getStringCellValue();
break;
case HSSFCell.CELL_TYPE_BLANK:
value = "";
break;
case HSSFCell.CELL_TYPE_FORMULA:
value = cell.getCellFormula();
break;
default:
break;
}
values[rowPos][cell.getColumnIndex()] = value;
}
rowPos++;
}
}

Below is what worked for me. The "row.CREATE_NULL_AS_BLANK" did not appear to be valid but that could be lack of NPOI knowledge.
HSSFCell dataCell= (HSSFCell)row.GetCell(column, NPOI.SS.UserModel.MissingCellPolicy.CREATE_NULL_AS_BLANK);

for(org.apache.poi.ss.usermodel.Row tmp : hssfSheet){
for(int i = 0; i<8;i++){
System.out.println(tmp.getCell(i));
}
}

This worked for me....
int rowNumber;
int previousCell;
int currentCell;
int currentRowNumber;
HSSFCell cell;
while (rows.hasNext()) {
previousCell = -1;
currentCell = 0;
while (cellIterator.hasNext()) {
cell = (HSSFCell) cellIterator.next();
currentCell = cell.getColumnIndex();
if (previousCell == currentCell-1) {
//...
}
else {
System.out.println("Blank cell found");
}
previousCell = currentCell;
}
}

List cellDataList = new ArrayList();
int lineNumber = 0;
while (rowIterator.hasNext()) {
HSSFRow hssfRow = (HSSFRow) rowIterator.next();
//System.out.println("Befor If");
lineNumber++;
if(lineNumber==1){continue;}
//System.out.println("Out side if ");
Iterator<Cell> iterator = hssfRow.cellIterator();
List<Cell> cellTempList = new ArrayList();
int current = 0, next = 1;
while (iterator.hasNext()) {
Cell hssfCell = iterator.next();
current = hssfCell.getColumnIndex();
if(current<next){
System.out.println("Condition Satisfied");
}
else{
int loop = current-next;
System.out.println("inside else Loop value : "+(loop));
for(int k=0;k<loop+1;k++){
System.out.println("Adding nulls");
cellTempList.add(null);
next = next + 1;
}
}
cellTempList.add(hssfCell);
next = next + 1;
System.out.println("At End next value is : "+next);
}
cellDataList.add(cellTempList);
}

public String[] rowToString(Row row)
{
Iterator<Cell> cells = row.cellIterator() ;
String[] data = new String[row.getLastCellNum()] ;
int previousCell = 0 ;
Cell cell = cells.next() ;
int currentCell = cell.getColumnIndex();
while (true)
{
if (previousCell == currentCell) {
switch (cell.getCellType()) {
case Cell.CELL_TYPE_NUMERIC:
data[previousCell] = cell.getNumericCellValue()+"" ;
break;
case Cell.CELL_TYPE_STRING:
data[previousCell] = cell.getStringCellValue() ;
break;
/* // there could be other cases here.
case Cell.CELL_TYPE_FORMULA:
data[previousCell] =eval.evaluateFormulaCell(cell);
break;
case Cell.CELL_TYPE_BOOLEAN:
data[previousCell] = cell.getBooleanCellValue();
break;
case Cell.CELL_TYPE_BLANK:
data[previousCell] = "";
break;
case Cell.CELL_TYPE_ERROR:
data[previousCell] = "ERROR";
break;
*/
}
if(cells.hasNext()){
cell = cells.next() ;
currentCell = cell.getColumnIndex();
} else {
break ;
}
} else {
data[previousCell] = "";
}
previousCell++ ;
}
return data ;
}

for (Row row: sheet){
// This will return null if cell is empty / blank
Cell cell = row.getCell(columnNumber);
}