Japanese characters not displayed properly in ReadOnlySharedStringsTable

Question

I have a problem regarding reading Japanese characters in my Excel file. The reader's constructor is:

public XExcelFileReader(final String excelPath) throws Exception {
    this.opcPkg = OPCPackage.open(excelPath, PackageAccess.READ);
    this.stringsTable = new ReadOnlySharedStringsTable(this.opcPkg);

    XSSFReader xssfReader = new XSSFReader(this.opcPkg);
    XMLInputFactory factory = XMLInputFactory.newInstance();
    InputStream inputStream = xssfReader.getSheetsData().next();
    this.xmlReader = factory.createXMLStreamReader(inputStream);

    while (this.xmlReader.hasNext()) {
      this.xmlReader.next();
      if (this.xmlReader.isStartElement()) {
        if (this.xmlReader.getLocalName().equals("sheetData"))
          break;
      }
    }
  }

At this point, stringsTable has Japanese characters such as 予算ヨサン but in the Excel file, it only reads as 予算 . Some are displayed as they appear in the Excel file but some are not. I'm not sure where it goes wrong and encoding is UTF-8.

I'm reading a large Excel file and I have tried creating a workbook but it gives out a memory error, so using that is not an option.

Any idea on where it could go wrong?

Answer 1

Found an answer. Modified the constructor to be:

public XExcelFileReader(final String excelPath) throws Exception {
    this.opcPkg = OPCPackage.open(excelPath, PackageAccess.READ);
    XSSFReader xssfReader = new XSSFReader(this.opcPkg);
    this.stringsTable = xssfReader.getSharedStringsTable();

    XMLInputFactory factory = XMLInputFactory.newInstance();
    InputStream inputStream = xssfReader.getSheetsData().next();
    this.xmlReader = factory.createXMLStreamReader(inputStream);

    while (this.xmlReader.hasNext()) {
      this.xmlReader.next();
      if (this.xmlReader.isStartElement()) {
        if (this.xmlReader.getLocalName().equals("sheetData")) {
          break;
        }
      }
    }
  }

and changed stringsTable to SharedStringsTable. I'm not really sure why XSSFReader had to go first. Anyone who can explain is more than welcome to do so.