CODEWITHSUNDEEP
javaspring-bootapache-kafkakafka-consumer-apispring-kafka
Gavin Smith
Gavin Smith

Reputation: 25

Can't convert value of class org.json.JSONObject to class org.apache.kafka.common.serialization.StringSerializer/ JsonSerializer

How looks my configurations:

Map<String, Object> props = kafkaProperties.buildProducerProperties();

props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

Which serializer should i use for JSONObject?

Should i send by kafkaTemplate JsonObject to it would be better to send String? (jsonObject.toString());

Upvotes: 1

Views: 1822

Answers (1)

JavaTechnical
JavaTechnical

Reputation: 9347

It is always recommended to use a specific serializers for Kafka producer instead of using StringSerializer. The reason is that, string is very generic and it can be either a vaild or invalid JSON string.

If you use StringSerializer, the KafkaProducer serializer does not complain if the given string is a valid JSON or not.

So, in future if some developer tries to send a malformed JSON string, it can affect the consumer. Also, the serializer that you would write can be reusable for similar use-cases.

So, better write a new serializer which validates the JSON string (or) write JSONObjectSerializer or even a serializer for your custom POJO class (if you have any).

public class JSONObjectSerializer implements Serializer<JSONObject> {
    public byte[] serialize(String topic, JSONObject data) {
       return data.toString().getBytes(); // or whatever is appropriate.
    }
}

You anyway have to convert it to JSON, the point is that instead of doing in your main logic (KafkaProducer), you write that in a Serializer

In case you want to convert any object to JSON.

private ObjectMapper objectMapper = new ObjectMapper();
public byte[] serialize(String topic, Object data) {
   return objectMapper.writeValueAsBytes(data);
}

Upvotes: 2

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