How does avro binary encode my json string into an byte array?

Question

I have an actual JSON string that I need for avro binary coding for a byte array. After going through the Apache Avro spec, I came up with the code below.

I'm not sure if this is the right way to do this or not. Can anyone take a look if I am trying to set the avro binary to my JSON String correctly? I am using Apache Avro version 1.7.7.

public class AvroTest { private static final String json = "{" + "\"name\":\"Frank\"," + "\"age\":47" + "}"; private static final String schema = "{ \"type\":\"record\", \"namespace\":\"foo\", \"name\":\"Person\", \"fields\":[ { \"name\":\"name\", \"type\":\"string\" }, { \"name\":\"age\", \"type\":\"int\" } ] }"; public static void main(String[] args) throws IOException { byte[] data = jsonToAvro(json, schema); String jsonString = avroToJson(data, schema); System.out.println(jsonString); } /** * Convert JSON to avro binary array. * * @param json * @param schemaStr * @return * @throws IOException */ public static byte[] jsonToAvro(String json, String schemaStr) throws IOException { InputStream input = null; GenericDatumWriter<Object> writer = null; Encoder encoder = null; ByteArrayOutputStream output = null; try { Schema schema = new Schema.Parser().parse(schemaStr); DatumReader<Object> reader = new GenericDatumReader<Object>(schema); input = new ByteArrayInputStream(json.getBytes()); output = new ByteArrayOutputStream(); DataInputStream din = new DataInputStream(input); writer = new GenericDatumWriter<Object>(schema); Decoder decoder = DecoderFactory.get().jsonDecoder(schema, din); encoder = EncoderFactory.get().binaryEncoder(output, null); Object datum; while (true) { try { datum = reader.read(null, decoder); } catch (EOFException eofe) { break; } writer.write(datum, encoder); } encoder.flush(); return output.toByteArray(); } finally { try { input.close(); } catch (Exception e) { } } } /** * Convert Avro binary byte array back to JSON String. * * @param avro * @param schemaStr * @return * @throws IOException */ public static String avroToJson(byte[] avro, String schemaStr) throws IOException { boolean pretty = false; GenericDatumReader<Object> reader = null; JsonEncoder encoder = null; ByteArrayOutputStream output = null; try { Schema schema = new Schema.Parser().parse(schemaStr); reader = new GenericDatumReader<Object>(schema); InputStream input = new ByteArrayInputStream(avro); output = new ByteArrayOutputStream(); DatumWriter<Object> writer = new GenericDatumWriter<Object>(schema); encoder = EncoderFactory.get().jsonEncoder(schema, output, pretty); Decoder decoder = DecoderFactory.get().binaryDecoder(input, null); Object datum; while (true) { try { datum = reader.read(null, decoder); } catch (EOFException eofe) { break; } writer.write(datum, encoder); } encoder.flush(); output.flush(); return new String(output.toByteArray()); } finally { } } } 

Answer 1

It seems to work at least. This can be simplified: loops are useless since having multiple objects will invalidate JSON. It may also be a good idea to avoid unnecessary analysis of the circuit by preparing it.

Here is my version:

 public class AvroTest { private static final String JSON = "{" + "\"name\":\"Frank\"," + "\"age\":47" + "}"; private static final Schema SCHEMA = new Schema.Parser().parse("{ \"type\":\"record\", \"namespace\":\"foo\", \"name\":\"Person\", \"fields\":[ { \"name\":\"name\", \"type\":\"string\" }, { \"name\":\"age\", \"type\":\"int\" } ] }"); public static void main(String[] args) throws IOException { byte[] data = jsonToAvro(JSON, SCHEMA); String jsonString = avroToJson(data, SCHEMA); System.out.println(jsonString); } /** * Convert JSON to avro binary array. * * @param json * @param schema * @return * @throws IOException */ public static byte[] jsonToAvro(String json, Schema schema) throws IOException { DatumReader<Object> reader = new GenericDatumReader<>(schema); GenericDatumWriter<Object> writer = new GenericDatumWriter<>(schema); ByteArrayOutputStream output = new ByteArrayOutputStream(); Decoder decoder = DecoderFactory.get().jsonDecoder(schema, json); Encoder encoder = EncoderFactory.get().binaryEncoder(output, null); Object datum = reader.read(null, decoder); writer.write(datum, encoder); encoder.flush(); return output.toByteArray(); } /** * Convert Avro binary byte array back to JSON String. * * @param avro * @param schema * @return * @throws IOException */ public static String avroToJson(byte[] avro, Schema schema) throws IOException { boolean pretty = false; GenericDatumReader<Object> reader = new GenericDatumReader<>(schema); DatumWriter<Object> writer = new GenericDatumWriter<>(schema); ByteArrayOutputStream output = new ByteArrayOutputStream(); JsonEncoder encoder = EncoderFactory.get().jsonEncoder(schema, output, pretty); Decoder decoder = DecoderFactory.get().binaryDecoder(avro, null); Object datum = reader.read(null, decoder); writer.write(datum, encoder); encoder.flush(); output.flush(); return new String(output.toByteArray(), "UTF-8"); } }