使用Apache POI从Excel的单列访问数据

Question

My input data

1. I have attached an Excel column with few rows
2. Number 445.04 is repeated thrice in this column.
3. I have to write a logic in java which will help me iterate through this column with 200+ rows and add these type of values will result in zero.
4. The numbers can be different, take up any value where the possibility of them when operated can result in zero.
5. Here's another picture with different scenerio
6. In the above, 10 and -3-7 when added can be made zero and also 5 and -5 can also be made zero. 7.How can i write the code which can access a single column for this type of scenario? Leave a comment if anything additional is required.

This is what I'm trying to achieve...the output can be printed on console of the IDE instead in the excel itself

Expected result

---

    Iterator<Row> iterator = firstSheet.iterator();
    List<Double> posValue = new ArrayList<Double>();
    List<Double> negValue = new ArrayList<Double>();
    while(iterator.hasNext())//goes down the row, until there is nothing
    {    
        Row nexRow = iterator.next();
        if(nexRow.getRowNum()!=0){
            value = nexRow.getCell(3).getNumericCellValue();

            if(value>0){
                posValue.add(value);
            }
            else if(value <0){
                //System.out.println("ehre");
                negValue.add(value);
            }
        }
        Iterator<Double> pIterator = posValue.iterator();
        Iterator<Double> nIterator = negValue.iterator();

        for(int i = 0; i<posValue.size();i++){
            for(int j=0; j<negValue.size(); j++){
                //System.out.println(negValue.get(j));
                result= posValue.get(i)+negValue.get(j);
            }
        }
        if(result==0){
            System.out.println(result+"    "+nexRow.getRowNum());
        }
        workbook.close();
        inputStream.close();
    }

I thought of this because I have to calculate the values on the basis their signs and make it zero.

Answer 1

You will need to iterate though the rows using a loop of some kind. This should help you.

public static void main(String[] args) throws IOException {
    String excelFilePath = "Book1.xlsx";
    FileInputStream inputStream = new FileInputStream(new File(excelFilePath));

    Workbook workbook = new XSSFWorkbook(inputStream);
    XSSFSheet firstSheet = (XSSFSheet) workbook.getSheetAt(0);
    Iterator<Row> iterator = firstSheet.iterator();
    iterator.next();// skip the header row
    Double result = 0.0;

    while (iterator.hasNext()) {
        Row nextRow = iterator.next();
        result += nextRow.getCell(0).getNumericCellValue();
    }
    System.out.println(result);

    workbook.close();
    inputStream.close();
}

Excel doc.

Answer 2

    Workbook workbook = new XSSFWorkbook(inputStream);
    Sheet firstSheet = workbook.getSheetAt(0);
    double addedValue = 0;
    double value = 0;
    List<Double> value1 = new ArrayList<Double>();
    double result =0;
    Iterator<Row> iterator = firstSheet.iterator();
    List<Double> posValue = new ArrayList<Double>();
    double negValue = 0;
    while(iterator.hasNext())//goes down the row, until there is nothing
    {    
        Row nexRow =iterator.next();
        if(nexRow.getRowNum()!=0)
        {
            value = nexRow.getCell(3).getNumericCellValue();
            value1.add(value);
            for(int i=0; i<value1.size();i++)
            {
                //For storing all the values 
                addedValue=value1.get(i);


                /* Checking if the values are negative or not 
          If it is, then convert it to positive */
                if(addedValue<0)
                {                         
                    negValue=Math.abs(value1.get(i));
                }
            }
            /*checking for the numbers which can be operated to make it zero
               and then displaying the row numbers which have been cancelled out*/

            if(addedValue==negValue)
            {
                result = addedValue-negValue;
                nexRow.getCell(3).setCellValue(0.0);
                System.out.println(result+"  Matched rows--> "+nexRow.getRowNum());

            }
        }
        workbook.close();
        inputStream.close();
    }
}

}

This is what I was trying to achieve. It will make the rows zero where the values can be operated on. @Piyush