I am trying to delete empty cell in apache-poi. I get this error at
unmarkedColumns.remove(unmarkedColumns.get(i)):
There is a problem with remove method.
I don't understand why.Can you help me?
java.lang.UnsupportedOperationException: null
at java.util.AbstractList.remove(Unknown Source)
at java.util.AbstractList$Itr.remove(Unknown Source)
)
Integer[] integers = new Integer[headers.size()];
Arrays.fill(integers, 0);
List<Integer> unmarkedColumns = Arrays.asList(integers);
for (ScoredFormData scoredFormData : scoredFormDatas) {
Row dataRow = sheet.createRow(++rownum);
List<Object> rowValues = prepareExportRow(scoredFormData, visitManager, parameters,
dynamicDatamanager,
scoreCriteriaDefinitions);
for (int i = 0; i < rowValues.size(); i++) {
if (unmarkedColumns.get(i) != 1 && rowValues.get(i) != null
&& !rowValues.get(i).equals("")) {
unmarkedColumns.set(i, 1);
}
}
populateCells(rowValues, dataRow);
}
for (int i = 0; i < unmarkedColumns.size(); i++) {
if (unmarkedColumns.get(i) == 0) {
Iterator<Row> rowIterator = sheet.iterator();
while (rowIterator.hasNext()) {
Row row = rowIterator.next();
Boolean changed = false;
for (int j = i + 1; j < row.getLastCellNum() + 1; j++) {
Cell oldCell = row.getCell(j - 1);
if (oldCell != null) {
row.removeCell(oldCell);
changed = true;
Cell nextCell = row.getCell(j);
if (nextCell != null) {
Cell newCell = row.createCell(j - 1, nextCell.getCellType());
switch (newCell.getCellType()) {
case Cell.CELL_TYPE_BOOLEAN: {
newCell.setCellValue(nextCell.getBooleanCellValue());
break;}}}}
if (changed ) {
unmarkedColumns.remove(unmarkedColumns.get(i));
i = 0;
}
}
Arrays.asList(..) returns a List with a fixed size, so you can't expand or shrink it.
To fix it, you could wrap it in an ArrayList:
List<Integer> unmarkedColumns = new ArrayList<>(Arrays.asList(integers));
Your problem is here
List<Integer> unmarkedColumns = Arrays.asList(integers);
If you use Arrays.asList(...), it returns a fixed size list, therefore you cannot remove elements from it.
You could make a workaround by wrapping it:
List<Integer> list = new ArrayList<Integer>(Arrays.asList(integers));
Related
I am trying to make use of Apache POI to read an excel file and convert it to a 2-dimensional object array. Attached is the code section.
Workbook workbook = new XSSFWorkbook(inputStream);
Sheet firstSheet = workbook.getSheetAt(1);
int numRows = 3;
int cols = 5;
double[][] excelData = new double[numRows][cols];
for (int i = 1; i < numRows; i++) {
Row row = firstSheet.getRow(i);
if (row != null) {
for (int j = 1; j < cols; j++) {
Cell cell = row.getCell(j);
if (cell != null) {
try {
excelData[i][j] = cell.getNumericCellValue();
} catch (IllegalStateException e) {
System.out.println("Cell data is not a double");
}
}
}
}
}
workbook.close();
inputStream.close();
return excelData;
}
enter image description here This is my excel sheet and I want to "just" read the blue part of it as a 2d array, but after running the code the first row and column all are zero and I don't want it, appreciate your help on how can quickly pull out all the zeros enter image description here.
You need to change index in the 1st loop to 0 (first field in excel file)
but in row you must provide index + 1 bc you need to read from the 2nd field.
Same analogy for 2nd loop and cell field
Workbook workbook = new XSSFWorkbook(new File("d:\\book1.xlsx"));
Sheet firstSheet = workbook.getSheetAt(1);
int numRows = 3;
int cols = 5;
double[][] excelData = new double[numRows][cols];
for (int i = 0; i < numRows; i++) {
Row row = firstSheet.getRow(i + 1);
if (row != null) {
for (int j = 0; j < cols; j++) {
Cell cell = row.getCell(j + 1);
if (cell != null) {
try {
if (cell.getCellType().equals(CellType.NUMERIC)) {
excelData[i][j] = Double.valueOf(cell.getNumericCellValue());
}
} catch (IllegalStateException e) {
System.out.println("Cell data is not a double");
}
}
}
}
}
workbook.close();
Returned result for it:
0.041256 0.033079 -0.01138 -0.02138 -0.01138
0.041256 0.033079 -0.01138 -0.01138 -0.01138
0.020628 0.01654 -0.00569 -0.10569 -0.00569
I don't know how to delete row without leaving an empty row.
I am using Apache POI 3.9 and I am getting an error using the following code:
public List<MeterInfo> addToList(String patternt) throws ParseException, IOException {
List<Object> data = new ArrayList<Object>();
int lastRowNum = sheet.getLastRowNum();
Row row;
for(int i = 0; i < lastRowNum; i++){
row = sheet.getRow(i);
if(patternt.equals(getCurrentString(row))){
data.add(getDataFromRow(row));
sheet.removeRow(row);
sheet.shiftRows(row.getRowNum() + 1, row.getRowNum() + 1, -1);
}
}
saveWorkbook(new File("blabla.xlsx"));
return data;
}
I've found a solution in https://stackoverflow.com/a/3554129/6812826, but I am getting a NullPointerException because I am decreasing lastRowNum by each deleted row.
Here is the new version:
public List<Object> addToList(String pattern) throws ParseException, IOException {
List<Object> data= new ArrayList<Object>();
for (int i = 0; i <= sheet.getLastRowNum(); i++) {
Row row = sheet.getRow(i);
if (pattern.equals(getCurrentString(row))) {
data.add(getMeterInfo(row));
deleteRow(row);
}
}
saveWorkbook(new File("blabla.xlsx"));
return data;
}
private void deleteRow(Row row) {
int lastRowNum = sheet.getLastRowNum();
int rowIndex = row.getRowNum();
if(rowIndex >= 0 && rowIndex < lastRowNum){
sheet.shiftRows(rowIndex + 1, lastRowNum, -1);
}
if(rowIndex == lastRowNum){
Row removingRow = sheet.getRow(rowIndex);
if(removingRow != null){
sheet.removeRow(removingRow);
}
}
}
Try this code, it should work:
for(int i = 0; i < sheet.getLastRowNum(); i++)
{
row = sheet.getRow(i);
if(patternt.equals(getCurrentString(row)))
{
data.add(getDataFromRow(row));
// sheet.removeRow(row); NO NEED FOR THIS LINE
sheet.shiftRows(row.getRowNum() + 1, sheet.getLastRowNum() + 1, -1);
i--;
}
}
You need to decrease i by one every time you delete one row. And get the last row number again by using getLastRowNum().
I try to traverse some excel2007 data by using poi.jar based on jdk1.6.But when I seem to find a strange phenomenon that when I traverse the row(stored by HashMap()) and then add the row data to java.util.ArrayList .
And starting the next iterator,I first clear the row data by invoking Map.clear(), but when again invoking the ArrayList.add() method,this row data is overridden the older data.
Map<String, String> cellForRow = = new HashMap<String, String>();
List<Map<String, String>> rowForSheet = new ArrayList<Map<String, String>>();
for (int j = 0; j < sheet.getPhysicalNumberOfRows(); j++) {
row = sheet.getRow(j);
if (j == 0) {// the first row is title
titleRow = row;
continue;
}
if (row != null && titleRow.getPhysicalNumberOfCells() > 0) {
// cellForRow = new HashMap<String, String>();
cellForRow.clear();
for (int k = 0; k < titleRow.getPhysicalNumberOfCells(); k++) {// cell
cellForRow.put(getCellValue(titleRow.getCell(k)), getCellValue(row.getCell(k)));
}
}
rowForSheet.add(cellForRow);
}
Next Snippets show the debug log for rowForSheet(List)
[{ Up =Stream, Email=XXX,Down =Stream},
{ Up =Stream, Email=XXX,Down =Stream},
{ Up =Stream, Email=XXX,Down =Stream},
{ Up =Stream, Email=XXX,Down =Stream},
{ Up =Stream, Email=XXX,Down =Stream}]
the later data override the older data
Did you?
First off, I would put the creation of your map inside of the loops so you add a new map each time.
List<Map<String, String>> rowForSheet = new ArrayList<Map<String, String>>();
for (int j = 0; j < sheet.getPhysicalNumberOfRows(); j++) {
row = sheet.getRow(j);
if (j == 0) {// the first row is title
titleRow = row;
continue;
}
Map<String, String> cellForRow = = new HashMap<String, String>();
if (row != null && titleRow.getPhysicalNumberOfCells() > 0) {
for (int k = 0; k < titleRow.getPhysicalNumberOfCells(); k++) {// cell
cellForRow.put(
getCellValue(titleRow.getCell(k)),
getCellValue(row.getCell(k))
);
}
}
rowForSheet.add(cellForRow);
}
Now each item in the list will be a different map, with the new data you've added.
I wish to read an Excel file and skip the empty rows. My code skips empty cells but it skips empty columns, too. How can I skip empty rows but maintain empty columns? I'm using JXL Java.
for (int i = 0; i < sheet.getRows(); i++) {
for (int j = 0; j < sheet.getColumns(); j++) {
Cell cell = sheet.getCell(j, i);
String con = cell.getContents();
if (con != null && con.length() != 0) {
System.out.print(con);
System.out.print("|");
}
else {
continue;
}
}
}
Try this:
for (int i = 0; i < sheet.getRows(); i++) {
boolean rowEmpty = true;
String currentRow = "";
for (int j = 0; j < sheet.getColumns(); j++) {
Cell cell = sheet.getCell(j, i);
String con=cell.getContents();
if(con !=null && con.length()!=0){
rowEmpty = false;
}
currentRow += con + "|";
}
if(!rowEmpty) {
System.out.println(currentRow);
}
}
What you were doing is:
Loop through rows
Loop through columns
Print cell if it's empty only, skip it otherwise (your continue statement does nothing as it's the last instruction in the loop anyway, and a break statement would just stop reading the row once it reaches an empty cell)
What this does is:
Loop through rows
Loop through columns
Append the cell to the row's string, and if it's non-empty then set rowEmpty to false (as it contains at least one non-empty cell)
Print the row only if it's not empty
In case of C#, This works for me
private bool CheckIfEmptyRow(ISheet worksheet, int rowIndex)
{
var worksheetRow = worksheet.GetRow(rowIndex);
bool isRowEmpty = true;
for (var columnIndex = worksheetRow.FirstCellNum; columnIndex < worksheetRow.LastCellNum; columnIndex++)
{
ICell cell = worksheetRow.GetCell(columnIndex, MissingCellPolicy.RETURN_NULL_AND_BLANK);
if (!string.IsNullOrEmpty(cell.StringCellValue))
{
isRowEmpty = false;
break;
}
}
return isRowEmpty;
}
I am new to Apache-poi and using 3.8 version of poi. While writing value in the Excel,i check for the column names if they matched, i will write some value in that column and finish it, and again i will start writing on header. The problem is if write three column values only last column values are add or saved and first two values are not saved in the column. Can anyone tell what went wrong.
(sorry, in case any mistake)
Code:
int i = 0;
Row row = sheet.createRow(i);
CellStyle cellStyle = workbook.createCellStyle();
cellStyle.setFillBackgroundColor(HSSFColor.LIGHT_ORANGE.index);
String validate_header = null;
while (iterator.hasNext()) {
if (eiterator.hasNext()) {
validate_header = eiterator.next();
}
Cell cell = row.createCell(i);
String col_heading = iterator.next();
cell.setCellValue(col_heading);
if(col_heading.equalsIgnoreCase("Assigned Date"))
{
Add_value(i, col_heading, row, sheet);
row=sheet.getRow(0);
cell=row.getCell(i);
}
else if(col_heading.startsWith("Review"))
{
int count=-1;
int n=Col_values.get("Defect Summary").size();
for (int j = 0; j < n; j++) {
row = sheet.createRow(count);
cell = row.createCell(i);
String s="External QC Defect ";
cell.setCellValue(s);
count++;
}
row=sheet.getRow(0);
cell=row.getCell(i);
}
sheet.autoSizeColumn(i);
i++;
}
private static Sheet Add_value(int k,String name,Row row, Sheet sheet) {
System.out.println("Inside the add method");
if(name.equalsIgnoreCase("Assigned Date")||name.equalsIgnoreCase("Reported Date") )
{
vector = Col_values.get("TargetDate");
int count = 1;
System.out.println("IF Size of the vector " + vector.size());
for (int j = 0; j < vector.size(); j++) {
row = sheet.createRow(count);
cell = row.createCell(k);
String s = (String) vector.get(j);
System.out.println(s);
cell.setCellValue(s);
count++;
}
}
else
{
vector = Col_values.get("Defect Summary");
int count = 1;
System.out.println("ELSE Size of the vector " + vector.size());
for (int j = 0; j < vector.size(); j++) {
row = sheet.createRow(count);
cell = row.createCell(k);
String s = (String) vector.get(j);
System.out.println(s);
cell.setCellValue(s);
count++;
}
}
return sheet;
}
'
Can u tell what went Wrong?
It seems that Add_value starts creating rows from top. Therefore on the second call the old rows are removed.
Replace
row = sheet.createRow(count);
with
row = k == 0 ? sheet.createRow(count) : sheet.getRow(count);