private void generateJsonFromWritable(Writable value, int fieldIndex, String label, PrimitiveObjectInspector poi,
      JsonGenerator jsonGen) throws IOException {
    Object prim = poi.getPrimitiveJavaObject(value);
    Long epoch = HiveShims.getPrimitiveEpoch(prim, tz);
    if (epoch == null) {  // anything but a recognized DATE or TIMESTAMP
      jsonGen.writeObjectField(label, prim);
    } else {
      jsonGen.writeObjectField(label, epoch);
    }
  }
Send to the generator, the value of the cell, using column type

@param value The attribute value as the object given by Hive
@param fieldIndex column index of field in row
@param jsonGen JsonGenerator
@throws JsonProcessingException
@throws IOException
ql/src/java/org/apache/hadoop/hive/ql/udf/esri/serde/BaseJsonSerDe.java