bug 61053 -- not a fix, but this aligns XSSFBSheetHandler's behavior with streaming and non-streaming extractors for xlsx

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1799345 13f79535-47bb-0310-9956-ffa450edef68

src/ooxml/java/org/apache/poi/xssf/binary/XSSFBSheetHandler.java

 import java.io.InputStream;
 import java.util.Queue;
 
+import org.apache.poi.ss.usermodel.BuiltinFormats;
 import org.apache.poi.ss.usermodel.DataFormatter;
 import org.apache.poi.ss.util.CellAddress;
 import org.apache.poi.util.Internal;
     private String formatVal(double val, int styleIdx) {
         String formatString = styles.getNumberFormatString(styleIdx);
         short styleIndex = styles.getNumberFormatIndex(styleIdx);
+        //for now, if formatString is null, silently punt
+        //and use "General".  Not the best behavior,
+        //but we're doing it now in the streaming and non-streaming
+        //extractors for xlsx.  See BUG-61053
+        if (formatString == null) {
+            formatString = BuiltinFormats.getBuiltinFormat(0);
+            styleIndex = 0;
+        }
         return dataFormatter.formatRawCellContents(val, styleIndex, formatString);
     }