public static String convertToString(org.apache.hadoop.hive.metastore.api.Timestamp val) {
    if (val == null) {
      return "";
    }

    TimestampWritableV2 writableValue = new TimestampWritableV2(Timestamp.ofEpochSecond(val.getSecondsSinceEpoch()));
    return writableValue.toString();
  }
Creates a String from the properties in this format:
   'property_name1'='property_value1',
   'property_name2'='property_value2',
   ...

Properties are listed in alphabetical order.

@param properties The properties to list.
@param exclude Property names to exclude.
ql/src/java/org/apache/hadoop/hive/ql/ddl/ShowUtils.java