CODEWITHSUNDEEP
javaapache-poi
Coder
Coder

Reputation: 235

Apache POI - Handling Empty fields

I am new to Apache POI, and I need to write to an excel file based on the contents of my DB. However, when there is an empty/null field in the DB, a Null Pointer Exception is thrown for that particular field. I've been reading about Missing Cell Policies, is this the best way to address this? I have omitted a lot of code for brevity, but the below is the key part. For example if actualAmountReturned is empty in the DB, a NPE is thrown.

        List<CaseData> cases = (List<CaseData>) model.get("cases");
    int rowCount = 1;
    for (CaseData pieCase : cases) {
        Row userRow = sheet.createRow(rowCount++);
        userRow.createCell(0).setCellValue(pieCase.getCaseId());
        userRow.createCell(1).setCellValue(pieCase.getAcknowledgementReceivedDate());
        userRow.createCell(2).setCellValue(pieCase.getActualAmountReturned());
}

Upvotes: 0

Views: 1030

Answers (1)

Axel Richter
Axel Richter

Reputation: 61860

There are only two Cell.setCellValue methods which will throw NPE when the given value is null. This are the two only ones which take primitive data types as value parameters but you put the appropriate object wrapper classes so unboxing is necessary. This are Cell.setCellValue(boolean value) and Cell.setCellValue(double value). This is because unboxing from Boolean to boolean and Double to double fails for null.

For example

Boolean value = null;
cell.setCellValue(value); //NPE because unboxing `Boolean` to `boolean` fails

and 

Double value = null;
cell.setCellValue(value); //NPE because unboxing `Double` to `double` fails

All other Cell.setCellValue methods which take non primitive data classes as value parameters simple create blank cells when null is given.

So if pieCase.getActualAmountReturned() returns a Double, then

...
if (pieCase.getActualAmountReturned() == null) {
 userRow.createCell(2).setBlank();
} else {
 userRow.createCell(2).setCellValue(pieCase.getActualAmountReturned());
}
...

Upvotes: 2

Related Questions