JSON Array Parsing Kafka

Question

I have the following setup: A Rest endpoint to accept JSON POST request: I am parsing the request and sending it as a String over Kafka. But getting parsing errors A Rest endpoint to accept JSON POST request:

[ { "Name": "Jack", "Id": "314", "Gender": "M" } , { "Name": "John", "Id": "451", "Gender": "M" }, { "Name": "Rita", "Id": "501", "Gender": "F" } ]

I am parsing the request as follows

@RequestMapping(method = RequestMethod.POST, value = "/record")
@ResponseBody
public String process(@RequestBody Map<String, Object>[] payload) throws 
Exception {
    String str = Arrays.toString(payload)
    KafkaProd.toTopic(str);
    System.out.println("Payload: " +str);
    return "Record Processed";
}


str = Arrays.toString(payload) is changing it into the following format
[ { Name = Jack , Id = 314, Gender = M } , { Name = John, Id = 451, 
Gender = M }, { Name = Rita, Id = 501, Gender = F } ]

When I'm trying to parse this string back into json array using json-s 
imple :

 JSONArray jsonArray = new JSONArray(record.value());
 for (int i = 0; i < jsonArray.length(); i++) {
 System.out.println("Json Objects : " 
 +jsonArray.getJSONObject(i).toString());
 }

I am getting JSON Parsing error, since the record.value() is not a valid json array

Option 1. How do I convert this to a valid json array? Option 2. How do I send the json array in a proper format through kafka?

Which of these options do I use?

Gary Russell · Accepted Answer · 2019-06-27 13:24:15Z

1

Instead of String str = Arrays.toString(payload) use a Jackson ObjectMapper to convert the map to a String.

answered Jun 27, 2019 at 13:24

Gary Russell

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3 Comments

Artem Bilan Over a year ago

I wonder what is the point to convert an incoming JSON into Map and then back to JSON for sending to Kafka... What is the point to convert request byte[] to JSON at all since we can simply send that byte[] to Kafka?!

Gary Russell Over a year ago

I was going to say the same, but I assumed this was just an example and his controller needs to examine the map contents.

MChiru Over a year ago

I'm using byte[] bytes = new ObjectMapper().writeValueAsString(payload).getBytes("utf-8") Thanks Gary for pointing me in the right direction, Artem for the byte[] suggestion.

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