将 Kafka 消息覆盖到 java object

Question

I am trying to convert a kafka message which is received as List of string into Json object.

Following is my code snippet:

        //Kafka consuming msg
        List<String> message = KafkaMessageConsumer.consumeMessage(props.getProperty("pickbegin.topicname"));
        System.out.println("Message:" +message);

I am getting the message from the kafka as:

Message:[{
"orders": [
  {
  "orderId": "784",
  "orderPriority": "REGULAR",
  "userId": "123"
  }
]

Now I am trying to covert into Java object:

My Pojo classes are as follows:

@Data
public class PickBeginJson {

@JsonProperty("orders")
private List<Order> mOrders;
}

And another POJO class is:

@Data
public class Order {
    @JsonProperty("orderId")
    private String mOrderId;
    @JsonProperty("orderPriority")
    private String mOrderPriority;
    @JsonProperty("userId")
    private String mUserId;
}

My code snippet where I am trying to covert into Java object is as follows:

        //Json to java object
        Gson gson = new Gson();
        for(String i : message)
        {
            JsonReader reader = new JsonReader(new StringReader(i));
            reader.setLenient(true);
            pickBeginJson = gson.fromJson(i, PickBeginJson.class);
            System.out.println("pickBeginJson"+pickBeginJson);
        }

I am getting an exception:

com.google.gson.JsonSyntaxException: com.google.gson.stream.MalformedJsonException: Unterminated object at line 6 column 4 path $.orders[0].

I have also used ObjectMapper as:

   for(String i : message)
   {
     pickBeginJson = objectMapper.readValue(i, PickBeginJson.class);
     System.out.println("pickBeginJson"+pickBeginJson);
   }

But I am getting an exception as:

com.fasterxml.jackson.databind.JsonMappingException: Unexpected character ('"' (code 34)): was expecting comma to separate Object entries
 at [Source: (String)"{
"orders": [
  {
  "orderId": "784",
  "orderPriority": "REGULAR"
  "userId": "123"
  }
]
}

Any help will be appreciated.

Answer 1

I have seen your problem, it is a malformed JSON as the error message states. Look at your JSON in the Kafka message:

   {
     "orders": [
       {
          "orderId": "784",
          "orderPriority": "REGULAR"
          "userId": "123"
       }
    ]

If you take a closer look will notice it is missing a comma between the "orderId" and "orderPriority". Also, it is missing a close bracket "}" in the end of the JSON.

Your JSON should be like this:

{
   "orders":[
      {
         "orderId":"784",
         "orderPriority":"REGULAR",
         "userId":"123"
      }
   ]
}