Json conversion: Convert one of the fields of the object as binary data

Json conversion: Convert one of the fields of the object as binary data

Problem statement: I had an object that I wanted to convert to JSON. However, one of the fields of this object was a serializable-blob and hence I wanted to save it in binary/byte-array format instead of String format.

Solution:

1.     Write a custom JsonSerializer and JsonDeserializer as shown below

2.     Annotate the getter/setter of the blob-field with this custom serializer/deserializer respectively.

Object:

public class TestObject {

      private String name = null;

      private MyBlob data = null;

      public TestObject() {

            super();

      }

      @JsonSerialize(using=ByteArraySerializer.class)

      public MyBlob getData() {

            return data;

      }

      @JsonDeserialize(as=MyBlob.class, using=ByteArrayDeserializer.class)

      public void setData(MyBlob data) {

            this.data = data;

      }

      public String getName() {

            return name;

      }

      public void setName(String name) {

            this.name = name;

      }

}

JsonSerializer:

//(You can find out some other object-serializer (or write your own) to avoid dependency over Cassandra-code)
import me.prettyprint.cassandra.serializers.ObjectSerializer;

import org.codehaus.jackson.JsonGenerator;

import org.codehaus.jackson.JsonProcessingException;

import org.codehaus.jackson.map.JsonSerializer;

import org.codehaus.jackson.map.SerializerProvider;

public class ByteArraySerializer extends JsonSerializer<Object> {

                @Override

                public void serialize(Object value, JsonGenerator jgen,

                                                SerializerProvider provider) throws IOException,

                                                JsonProcessingException {

                                byte[] bytes = ObjectSerializer.get().toBytes(value);

                                jgen.writeBinary(bytes);

                }

}

JsonDeserializer:

import java.io.IOException;

//(You can find out some other object-deserializer (or write your own) to avoid dependency over Cassandra-code)
import me.prettyprint.cassandra.serializers.ObjectSerializer;

import org.codehaus.jackson.JsonParser;

import org.codehaus.jackson.JsonProcessingException;

import org.codehaus.jackson.map.DeserializationContext;

import org.codehaus.jackson.map.JsonDeserializer;

public class ByteArrayDeserializer extends JsonDeserializer<Object> {

                @Override

                public Object deserialize(JsonParser jp, DeserializationContext ctxt)

                                                throws IOException, JsonProcessingException {

                                byte[] bytes = jp.getBinaryValue();

                                Object obj = ObjectSerializer.get().fromBytes(bytes);

                                return obj;

                }

}

-          Sarang Anajwala