parquet-hadoop/src/main/java/org/apache/parquet/hadoop/ParquetFileWriter.java
@Deprecated
  public static ParquetMetadata mergeMetadataFiles(List<Path> files,  Configuration conf) throws IOException {
    Preconditions.checkArgument(!files.isEmpty(), "Cannot merge an empty list of metadata");

    GlobalMetaData globalMetaData = null;
    List<BlockMetaData> blocks = new ArrayList<BlockMetaData>();

    for (Path p : files) {
      ParquetMetadata pmd = ParquetFileReader.readFooter(conf, p, ParquetMetadataConverter.NO_FILTER);
      FileMetaData fmd = pmd.getFileMetaData();
      globalMetaData = mergeInto(fmd, globalMetaData, true);
      blocks.addAll(pmd.getBlocks());
    }

    // collapse GlobalMetaData into a single FileMetaData, which will throw if they are not compatible
    return new ParquetMetadata(globalMetaData.merge(), blocks);
  }
@Deprecated
  public static ParquetMetadata mergeMetadataFiles(List<Path> files,  Configuration conf) throws IOException {
    Preconditions.checkArgument(!files.isEmpty(), "Cannot merge an empty list of metadata");

    GlobalMetaData globalMetaData = null;
    List<BlockMetaData> blocks = new ArrayList<BlockMetaData>();

    for (Path p : files) {
      ParquetMetadata pmd = ParquetFileReader.readFooter(conf, p, ParquetMetadataConverter.NO_FILTER);
      FileMetaData fmd = pmd.getFileMetaData();
      globalMetaData = mergeInto(fmd, globalMetaData, true);
      blocks.addAll(pmd.getBlocks());
    }

    // collapse GlobalMetaData into a single FileMetaData, which will throw if they are not compatible
    return new ParquetMetadata(globalMetaData.merge(), blocks);
  }
Given a list of metadata files, merge them into a single ParquetMetadata
Requires that the schemas be compatible, and the extraMetadata be exactly equal.
@param files a list of files to merge metadata from
@param conf a configuration
@return merged parquet metadata for the files
@throws IOException if there is an error while writing
@deprecated metadata files are not recommended and will be removed in 2.0.0