Databases
StackOverflow2013
Postsdbo
POApache POI Java Excel Performance for Large Spreadsheets
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POApache POI Java Excel Performance for Large Spreadsheets
    primarykey
    data
    text
    <p>I have a spreadsheet I'm trying to read with POI (I have both xls and xlsx formats), but in this case, the problem is with the xls file. My spreadsheet has about 10,000 rows and 75 columns, and reading it in can take several minutes (though Excel opens in a few seconds). I'm using the event based reading, rather than reading the whole file into memory. The meat of my code is below. It's a bit messy right now, but it's really just a long switch statement that was mostly copied from the POI examples.</p> <p>Is it typical for POI performance using the event model to be so slow? Is there anything I an do to speed this up? I think several minutes will be unacceptable for my application.</p> <pre><code> POIFSFileSystem poifs = new POIFSFileSystem(fis); InputStream din = poifs.createDocumentInputStream("Workbook"); try { HSSFRequest req = new HSSFRequest(); listener = new FormatTrackingHSSFListener(new HSSFListener() { @Override public void processRecord(Record rec) { thisString = null; int sid = rec.getSid(); switch (sid) { case SSTRecord.sid: strTable = (SSTRecord) rec; break; case LabelSSTRecord.sid: LabelSSTRecord labelSstRec = (LabelSSTRecord) rec; thisString = strTable.getString(labelSstRec .getSSTIndex()).getString(); row = labelSstRec.getRow(); col = labelSstRec.getColumn(); break; case RKRecord.sid: RKRecord rrk = (RKRecord) rec; thisString = ""; row = rrk.getRow(); col = rrk.getColumn(); break; case LabelRecord.sid: LabelRecord lrec = (LabelRecord) rec; thisString = lrec.getValue(); row = lrec.getRow(); col = lrec.getColumn(); break; case BlankRecord.sid: BlankRecord blrec = (BlankRecord) rec; thisString = ""; row = blrec.getRow(); col = blrec.getColumn(); break; case BoolErrRecord.sid: BoolErrRecord berec = (BoolErrRecord) rec; row = berec.getRow(); col = berec.getColumn(); byte errVal = berec.getErrorValue(); thisString = errVal == 0 ? Boolean.toString(berec .getBooleanValue()) : ErrorConstants .getText(errVal); break; case FormulaRecord.sid: FormulaRecord frec = (FormulaRecord) rec; switch (frec.getCachedResultType()) { case Cell.CELL_TYPE_NUMERIC: double num = frec.getValue(); if (Double.isNaN(num)) { // Formula result is a string // This is stored in the next record outputNextStringRecord = true; } else { thisString = formatNumericValue(frec, num); } break; case Cell.CELL_TYPE_BOOLEAN: thisString = Boolean.toString(frec .getCachedBooleanValue()); break; case Cell.CELL_TYPE_ERROR: thisString = HSSFErrorConstants .getText(frec.getCachedErrorValue()); break; case Cell.CELL_TYPE_STRING: outputNextStringRecord = true; break; } row = frec.getRow(); col = frec.getColumn(); break; case StringRecord.sid: if (outputNextStringRecord) { // String for formula StringRecord srec = (StringRecord) rec; thisString = srec.getString(); outputNextStringRecord = false; } break; case NumberRecord.sid: NumberRecord numRec = (NumberRecord) rec; row = numRec.getRow(); col = numRec.getColumn(); thisString = formatNumericValue(numRec, numRec .getValue()); break; case NoteRecord.sid: NoteRecord noteRec = (NoteRecord) rec; row = noteRec.getRow(); col = noteRec.getColumn(); thisString = ""; break; case EOFRecord.sid: inSheet = false; } if (thisString != null) { // do something with the cell value } } }); req.addListenerForAllRecords(listener); HSSFEventFactory factory = new HSSFEventFactory(); factory.processEvents(req, din); </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USDanilo Piazzalunga
    1. USJeff Storey
    plurals
    1. This table or related slice is empty.
    1. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POApache POI Java Excel Performance for Large Spreadsheets
      1. USjosh.trow
      1. VTFavorite
    2. VO
      singulars
      1. POApache POI Java Excel Performance for Large Spreadsheets
      1. USGrigory Katkov
      1. VTFavorite
    3. VO
      singulars
      1. POApache POI Java Excel Performance for Large Spreadsheets
      1. This table or related slice is empty.
      1. VTUpMod
    1. COIs it xls that is slow and xlsx that works fine? For me it is opposite, writing a file with many rows just uses some megabytes of heap for xls, but even 2GB wasn't enough for xlsx. I need to fallback to xls if output has more than X rows
      singulars
      1. POApache POI Java Excel Performance for Large Spreadsheets
      1. USrlovtang
    2. CO@rlovtang, xlsx is even slower. I just meant I am using POI instead of something like JExcel because I need to deal with both xls and xlsx.
      singulars
      1. POApache POI Java Excel Performance for Large Spreadsheets
      1. USJeff Storey
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload