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How to fetch duplicate records from excel and write into new file using java

I can read the data of one col 0 by using below code. I need to fetch the record for duplicate value present in col 0
FileInputStream fis = new FileInputStream(theNewestFile);
XSSFWorkbook workbook = new XSSFWorkbook(fis);
XSSFSheet spreadsheet = workbook.getSheetAt(0);
XSSFRow row;
String cellValueMaybeNull;
List<Cell> cells = new ArrayList<Cell>();
for (int rowIndex = 0; rowIndex <= spreadsheet.getLastRowNum(); rowIndex++) {
row = (XSSFRow) spreadsheet.getRow(rowIndex);
if (row != null) {
int colIndex = 0;
Cell cell = row.getCell(colIndex);
if (cell != null) {
// Found column and there is value in the cell.
cellValueMaybeNull = cell.getStringCellValue();
// Do something with the cellValueMaybeNull here ...
System.out.println(cellValueMaybeNull);
}
}
}

Declare a Map and capture all the duplicates and print it later. If the list size is more than 1 then it is duplicate case scenario.
FileInputStream fis = new FileInputStream(theNewestFile);
XSSFWorkbook workbook = new XSSFWorkbook(fis);
XSSFSheet spreadsheet = workbook.getSheetAt(0);
XSSFRow row;
String cellValueMaybeNull;
List<Cell> cells = new ArrayList<Cell>();
Map<String,List<String>> duplicateCheck = new HashMap<String,List<String>>();
for (int rowIndex = 0; rowIndex <= spreadsheet.getLastRowNum(); rowIndex++) {
row = (XSSFRow) spreadsheet.getRow(rowIndex);
if (row != null) {
int colIndex = 0;
Cell cell = row.getCell(colIndex);
if (cell != null) {
// Found column and there is value in the cell.
cellValueMaybeNull = cell.getStringCellValue();
// Do something with the cellValueMaybeNull here ...
if(duplicateCheck.get(cellValueMaybeNull) != null) {
duplicateCheck.get(cellValueMaybeNull).add(cellValueMaybeNull);
}
else {
List<String> list = new ArrayList<String>();
list.add(cellValueMaybeNull);
duplicateCheck.put(cellValueMaybeNull, list);
}
}
}
}
for(List<String> duplicateValue : duplicateCheck.values()) {
if(duplicateValue.size() > 1) {
System.out.println("Duplicate values :"+duplicateValue);
}
}

Trying to extract data and write to another spreadsheet comes up empty

The output file is created but only the first cell is written and nothing else. I tested it with system print and all the data that I want shows up in console but is not written to the worksheet.
public class excel_read_2 {
public static void main(String[] args)
{
try
{
FileInputStream file = new FileInputStream(new File("C:/Users/h.M/Desktop/20151007-110016_outgoing.xls")); //input
HSSFWorkbook workbook = new HSSFWorkbook(file);
HSSFSheet sheet = workbook.getSheetAt(0);
Workbook wb = new HSSFWorkbook();
Sheet sheet1 = wb.createSheet("new sheet");
FileOutputStream fileOut = new FileOutputStream("C:/Users/h.M/Desktop/workbook.xls"); //output
int rowcounter = 0;
for (int rowNum = 150; rowNum < 180; rowNum++) {
Row r = sheet.getRow(rowNum);
if (r == null) {
continue;
}
int lastColumn=6;
for (int cn = 0; cn < lastColumn; cn++) {
Cell c = r.getCell(cn, Row.RETURN_BLANK_AS_NULL);
if (c == null){
}
else if (c.getCellType() == HSSFCell.CELL_TYPE_STRING) {
Row row = sheet1.createRow((short)rowcounter);
Cell cell = row.createCell(cn);
row.createCell(cn).setCellValue(c.getStringCellValue());
System.out.println("The cell was a string \" " + c.getStringCellValue()+" \" ");
} else if (c.getCellType() == HSSFCell.CELL_TYPE_NUMERIC) {
Row row = sheet1.createRow((short)rowcounter);
Cell cell = row.createCell(cn);
row.createCell(cn).setCellValue(c.getNumericCellValue());
System.out.println("The cell was a number " + c.getNumericCellValue());
}
}
rowcounter++;
}
wb.write(fileOut);
fileOut.close();
file.close();
}
catch (Exception e)
{
e.printStackTrace();
}
}
}

Create the new row before you loop, then use it once per loop.
Row row = sheet1.createRow((short)rowcounter);
int lastColumn=6;
for (int cn = 0; cn < lastColumn; cn++) {
Cell c = r.getCell(cn, Row.RETURN_BLANK_AS_NULL);
if (c == null){
}
else if (c.getCellType() == HSSFCell.CELL_TYPE_STRING) {
Cell cell = row.createCell(cn);
cell.setCellValue(c.getStringCellValue());

Reading from excel file with blank cells to 2d array

I have a following code that reads logins and passwords from xls file starting from the second row(it skips column names) and writes it into a 2d array. But it only works if the sheet doesn't have blank cells in any of the rows. What should i do to make it work with empty cells?
private static Object[][] getUsersFromXls(String sheetName) {
final File excelFile = new File("src//resources//TestData.xls");
FileInputStream fileInputStream;
try {
fileInputStream = new FileInputStream(excelFile);
workbook = new HSSFWorkbook(fileInputStream);
} catch (IOException e) {
e.printStackTrace();
}
sheet = workbook.getSheet(sheetName);
final int numberOfRows = sheet.getLastRowNum();
final int numberOfColumns = sheet.getRow(0).getLastCellNum();
final String[][] xlsData = new String[numberOfRows][numberOfColumns];
String cellValue;
for (int i = 1; i <= numberOfRows; i++) {
final HSSFRow row = sheet.getRow(i);
for (int j = 0; j < numberOfColumns; j++) {
final HSSFCell cell = row.getCell(j);
final int cellType = cell.getCellType();
if (cellType == HSSFCell.CELL_TYPE_FORMULA) {
throw new RuntimeException("Cannot process a formula. Please change field to result of formula.");
} else {
cellValue = String.valueOf(cell);
xlsData[i - 1][j] = cellValue;
}
}
}
return xlsData;
}

Creating multiple sheets using Apache poi and servlets

When i am creating multiple sheets using Apache poi and servlets. It is creating the sheet but not writing the data to file. I am trying to write the first 1000 records to sheet1 and next 1000 to sheet2 through below code, but not working
private void writeDataToExcelFile(String string,
ArrayList<ArrayList<String>> excelData, OutputStream outputStream) {
HSSFWorkbook myWorkBook = new HSSFWorkbook();
String sheetName = "";
sheetName = "Document-" + 0;
HSSFSheet mySheet = myWorkBook.createSheet();
HSSFRow myRow = null;
HSSFCell myCell = null;
for (int rowNum = 0; rowNum < excelData.size(); rowNum++) {
ArrayList<String> rowData = excelData.get(rowNum);
if(rowNum>0 && rowNum%1000 == 0)
{
sheetName = "Document-" + (rowNum/1000);
mySheet = myWorkBook.createSheet();
}
myRow = mySheet.createRow(rowNum);
for (int cellNum = 0; cellNum < rowData.size(); cellNum++) {
myCell = myRow.createCell(cellNum);
myCell.setCellValue(rowData.get(cellNum));
}
}
System.out.println("Last row:" + mySheet.getLastRowNum());
System.out.println("Row number:" + mySheet.rowIterator().next().getRowNum());
try {
myWorkBook.write(outputStream);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
What is wrong with my logic.Please do the needful help.
Thanks

When you loop through the dataset, you are wanting to split at row 1000 to start a new sheet, which is fine, however when you start the new sheet, the next row you create is row 1001 (the outer loop index variable)
myRow = mySheet.createRow(rowNum);
To get the effect you wish, change the loop to be something like this:
int currentRow = 0;
for (int rowNum = 0; rowNum < excelData.size(); rowNum++)
{
ArrayList<String> rowData = excelData.get(rowNum);
if(currentRow == 1000)
{
sheetName = "Document-" + (rowNum/1000);
mySheet = myWorkBook.createSheet();
currentRow = 0;
}
myRow = mySheet.createRow(currentRow);
for (int cellNum = 0; cellNum < rowData.size(); cellNum++)
{
myCell = myRow.createCell(cellNum);
myCell.setCellValue(rowData.get(cellNum));
}
currentRow++;
}
I haven't compiled this, so I don't know if it'll work right away, but it should point you in the right direction.
HTH
Edit
Thinking about this further, you could get the same effect from making a 1 line change to the original application (albeit losing a little bit of clarity):
myRow = mySheet.createRow(rowNum%1000);

POI Appending .0 while reading numeric data from excel

I am using POI HSSF to read excel data and I am using JUnit to check the data against database proc RefCursor.
The Junit test fails as the numeric data from the Refcursor for example 100 are compared against the data in the excel sheet 100 but it fails as the POI reads it as 100.0.
InputStream fileInputStream = Testdb.class.getClassLoader().getResourceAsStream(fileName);
//retrieve number of columns and rows
int numRows=0, numCols=0, i, j, minColIndex=0, maxColIndex=0;
POIFSFileSystem fsFileSystem = new POIFSFileSystem(fileInputStream);
HSSFWorkbook workBook = new HSSFWorkbook(fsFileSystem);
HSSFSheet hssfSheet = workBook.getSheetAt(0);
Iterator rowIterator = hssfSheet.rowIterator();
while (rowIterator.hasNext())
{
numRows++;
HSSFRow hssfRow = (HSSFRow) rowIterator.next();
Iterator iterator = hssfRow.cellIterator();
List cellTempList = new ArrayList();
if (numRows == 1)
{
minColIndex = hssfRow.getFirstCellNum();
maxColIndex = hssfRow.getLastCellNum();
numCols = maxColIndex;
}
for(int colIndex = minColIndex; colIndex < maxColIndex; colIndex++)
{
HSSFCell hssfCell = hssfRow.getCell(colIndex);
cellTempList.add(hssfCell);
}
cellDataList.add(cellTempList);
}
String expected[][] = new String[numRows][numCols];
String[] tableColumns = new String[numCols];
System.out.println("Rows : " + numRows + "Columns : " + numCols);
System.out.println("Min Col Index : " +minColIndex + "Max Col Index : " + maxColIndex);
for (i=0; i<numRows; i++)
{
List cellTempList = (List) cellDataList.get(i);
for (j=0; j < numCols; j++)
{
HSSFCell hssfCell = (HSSFCell) cellTempList.get(j);
if (i == 0)
{
tableColumns[j] = hssfCell.toString();
System.out.print(tableColumns[j] + "\t");
}
else
{
if(hssfCell != null)
{
expected[i-1][j] = hssfCell.toString();
}
else
{
expected[i-1][j] = null;
}
System.out.print(expected[i-1][j] + "\t");
}
}
System.out.println();
}
This is a generic framework program which I am building so the framework should be intelligent enough to disregard the ".0".
Any inputs on how to resolve this?

This is virtually identical to a number of other questions here, such as returning decimal instead of string (POI jar)
The answer is the same as the one I gave here:
POI is giving you the exact value that Excel has stored in the File. Generally, if you write a number in an Excel cell, Excel will store that as a number with formatting. POI provides support to do that formatting for you if you want it (most people don't - they want the numbers as numbers so they can use them)
The class you're looking for is DataFormatter. Your code would be something like
DataFormatter fmt = new DataFormatter();
for (Row r : sheet) {
for (Cell c : r) {
CellReference cr = new CellRefence(c);
System.out.println("Cell " + cr.formatAsString() + " is " +
fmt.formatCellValue(c) );
}
}

Hi my solution was just to put the symbol:
'
in front of every number. Then the number is processed as text.
After you do that you would see little green triangle and warning:
For me this is not a problem, because it works.