Here are some utility fun= ctions we’ve used for serialization to and from JSON. Something simil= ar should work for binary.

<= /p>

public <T> String a= vroEncodeAsJson(Class<T> clazz, Object object) {

S= tring avroEncodedJson =3D null;

t= ry {

&= nbsp; if (object =3D=3D null || !(object instanceof Specif= icRecord)) {

&= nbsp; return null;

&= nbsp; }

&= nbsp; T record =3D (T) object;

&= nbsp; Schema schema =3D ((SpecificRecord) record).getSchem= a();

&= nbsp; ByteArrayOutputStream out =3D new ByteArrayOutputStr= eam();

&= nbsp; Encoder e =3D EncoderFactory.get().jsonEncoder(schem= a, out);

&= nbsp; SpecificDatumWriter<T> w =3D new SpecificDatum= Writer<T>(clazz);

&= nbsp; w.write(record, e);

&= nbsp; e.flush();

&= nbsp; avroEncodedJson =3D new String(out.toByteArray());&n= bsp;

}= catch (IOException e) {

&= nbsp; e.printStackTrace();

} = ;

<= /p>

return= avroEncodedJson;

}

<= /p>

public <T> T jsonDe= codeToAvro(String inputString, Class<T> className, Schema schema) {&n= bsp;

T= returnObject =3D null;

t= ry {

&= nbsp; JsonDecoder jsonDecoder =3D DecoderFactory.get().jso= nDecoder(schema, inputString);

&= nbsp; SpecificDatumReader<T> reader =3D new Specific= DatumReader<T>(className);

&= nbsp; returnObject =3D reader.read(null, jsonDecoder);&nbs= p;

}= catch (IOException e) {

&= nbsp; e.printStackTrace();

} = ;

&= nbsp;

r= eturn returnObject;

}

<= /p>

Dave

<= /p>

From: flaming.= zelda@gmail.com [mailto:flaming.zelda@gmail.com] On Behalf Of Gary Steelman
Sent: Tuesday, February 18, 2014 4:21 PM
To: user@avro.apache.org
Subject: General-Purpose Serialization and Deserialization for Avro-= Generated SpecificRecords

Hi all,

Here's my use case: I= 've got a bunch of different Java objects generated from Avro schema files.= So the class definition headers look something like this: public class MyO= bject extends org.apache.avro.specific.SpecificRecordBase implements org.apache.avro.specific.SpecificRecord. I've got many other ty= pes than MyObject too. I need to write a method which can serialize (from M= yObject or another class to byte[]) and deserialize (from byte[] to MyObjec= t or another class) in memory (not writing to disk).

I couldn't figure out= how to write one method to handle it for SpecificRecord, so I tired serial= izing/deserializing these things as GenericRecord instead:

public static byte[] serializeFromAvro(GenericRecord gr) {
    try {
      DatumWriter<GenericRecord> writer2 =3D= new GenericDatumWriter<GenericRecord>(gr.getSchema());
      ByteArrayOutputStream bao2 =3D new ByteArray= OutputStream();
      BinaryEncoder encoder2 =3D EncoderFactory.ge= t().directBinaryEncoder(bao2, null);
      writer2.write(gr, encoder2);
      byte[] avroBytes2 =3D bao2.toByteArray();       return avroBytes2;
    } catch (IOException e) {
      LOG.debug(e);
      return null;
    }
}

// Here I use a DataType enum and the AvroSch= emaFactory to quickly retrieve a Schema object for a supported DataType.

public static = GenericRecord deserializeFromAvro(byte[] avroBytes, DataType dataType) {     try {
      Schema schema =3D AvroSchemaFactory.getInsta= nce().getSchema(dataType);
      DatumReader<GenericRecord> reader2 =3D= new GenericDatumReader<GenericRecord>(schema);
      ByteArrayInputStream bai2 =3D new ByteArrayI= nputStream(avroBytes);
      BinaryDecoder decoder2 =3D DecoderFactory.ge= t().directBinaryDecoder(bai2, null);
      GenericRecord gr2 =3D reader2.read(null, dec= oder2);
      return gr2;
    } catch (Exception e) {
      LOG.debug(e);
      return null;
    }
}

And use them like suc= h:

// Remember MyObject is the SpecificRecord implement= ing class.

MyObject x =3D new MyObject();

byte[] avroBytes =3D serializeFromAvro(x);

MyObject x2 =3D (MyOb= ject) deserializeFromAvro(avroBytes, DataType.MyObject);

Which results in this= :
java.lang.ClassCastException: org.apache.avro.generic.GenericData$Record ca= nnot be cast to datatypes.generated.avro.MyObject

Is there an easier wa= y to achieve my use case, or some way I can fix my methods to allow the sor= t of behavior I want?

Thanks,

Gary