Java Read Parquet File to JSON Output

Question

Reading parquet file is working but getting indented format instead of a desired JSON output format. Any ideas? I was thinking that I may need to change GroupRecordConverter but wasn't able to find much documentation. If can point me to that, would also be helpful. Thanks very much for the help.

long num = numLines;
try {
  ParquetMetadata readFooter = ParquetFileReader.readFooter(conf, path, ParquetMetadataConverter.NO_FILTER);
  MessageType schema = readFooter.getFileMetaData().getSchema();
  ParquetFileReader r = new ParquetFileReader(conf,path,readFooter);

  PageReadStore pages = null;
  try{
    while(null != (pages = r.readNextRowGroup())) {
      final long rows = pages.getRowCount();
      System.out.println("Number of rows: " + rows);

      final MessageColumnIO columnIO = new ColumnIOFactory().getColumnIO(schema);
      final RecordReader recordReader = columnIO.getRecordReader(pages, new GroupRecordConverter(schema));
      String sTemp = "";
      for(int i=0; i<rows && num-->0; i++) {
        System.out.println(recordReader.read().toString())
      }
    }
  }
}

Current indented output:

data1: value1
data2: value2
models
  map
    key: data3
    value
      array: value3
  map
    key: data4
    value
      array: value4
data5: value5
...

Desired JSON output:

"data1": "value1",
"data2": "value2",
"models": {
    "data3": [
        "value3"
    ],
    "data4": [
        "value4"
    ]
},
"data5": "value5"
...

Answer 1

The java parquet lib's cat command tool code, might perhaps serve you as an example... containing the line:

org.apache.parquet.tools.json.JsonRecordFormatter.JsonGroupFormatter formatter = JsonRecordFormatter.fromSchema(metadata.getFileMetaData().getSchema());

See here for full source.