parquet-thrift/src/main/java/org/apache/parquet/thrift/ThriftMetaData.java
public static ThriftMetaData fromExtraMetaData(
      Map<String, String> extraMetaData) {
    final String thriftClassName = extraMetaData.get(THRIFT_CLASS);
    final String thriftDescriptorString = extraMetaData.get(THRIFT_DESCRIPTOR);
    if (thriftClassName == null || thriftDescriptorString == null) {
      return null;
    }
    final StructType descriptor = parseDescriptor(thriftDescriptorString);
    return new ThriftMetaData(thriftClassName, descriptor);
  }
public static ThriftMetaData fromExtraMetaData(
      Map<String, String> extraMetaData) {
    final String thriftClassName = extraMetaData.get(THRIFT_CLASS);
    final String thriftDescriptorString = extraMetaData.get(THRIFT_DESCRIPTOR);
    if (thriftClassName == null || thriftDescriptorString == null) {
      return null;
    }
    final StructType descriptor = parseDescriptor(thriftDescriptorString);
    return new ThriftMetaData(thriftClassName, descriptor);
  }
Reads ThriftMetadata from the parquet file footer.

@param extraMetaData  extraMetaData field of the parquet footer
@return the ThriftMetaData used to write a data file