JSON对象无法转换为JSON数组

Question

ya i know that it's very usual problem while mapping but my problem is some different hear is the scenario when my response have the data it gives me JSON Response like this

{
  "responseID": "110",
  "resultSet": [
    {
      "USERNAME": "Aninja",
      "position": "Developer",
      "salary": "60000"
    }
  ],
  "isSuccessful": true,
  "rtnCode": "0000"
}

and below is the same JSON response when data is not found

{
  "responseID": "123",
  "resultSet": {},
  "isSuccessful": true,
  "rtnCode": " "
}

as i can see hear when response have some data result set have JSON Array but when no data found we have JSON Object as a response

so this is the reason I'm getting this problem. so my question is that how should i handle this problem thanks for your response

Edit: the main problem is that i have made my model like list of JSON Object it works fine when there is result but it gives me error Can't convert JSON Object to JSON Array when result is empty s please suggest me how can i hanle it I'm using Jackson 2.2 i have also tried @JsonInclude(Include.NON_EMPTY) and @JsonInclude(Include.NON_NULL)

Answer 1

I wouldn't say it is mistake from server or back-end. But it is always a good practice to provide appropriate "Null Object Pattern" which describes the uses of such objects and their behavior.

So for better practice array which doesn't have any values should be sent back using "[]". So in this case "resultSet" should be given as [] instead of {} so it can be easily understood at front-end.

There are number of examples here which shows why it is useful to follow Null Object Pattern.

For example, if you are returning count in you response and there is no count then it is better to use "0" instead of "null".