public void encryptColumns(
      String inputFile, String outputFile, List<String> paths, FileEncryptionProperties fileEncryptionProperties)
      throws IOException {
    Path inPath = new Path(inputFile);
    Path outPath = new Path(outputFile);
    RewriteOptions options = new RewriteOptions.Builder(conf, inPath, outPath)
        .encrypt(paths)
        .encryptionProperties(fileEncryptionProperties)
        .build();
    ParquetRewriter rewriter = new ParquetRewriter(options);
    rewriter.processBlocks();
    rewriter.close();
  }
@Test
  public void testFlatColumn() throws IOException {
    String[] encryptColumns = {"DocId"};
    testSetup("GZIP");
    columnEncryptor.encryptColumns(
        inputFile.getFileName(),
        outputFile,
        Arrays.asList(encryptColumns),
        EncDecProperties.getFileEncryptionProperties(encryptColumns, ParquetCipher.AES_GCM_CTR_V1, false));
    verifyResultDecryptionWithValidKey();
  }