I've searched Stack Overflow before posting, but there were no solutions for Jackson.
Here is a server response:
{
"ok": true,
"result": [
{
"update_id": 489881731,
//rest
},
{
"update_id": 489881732,
//rest
}
]
}
As you see property "result"
is an array.
Now this is another response:
{
"ok": true,
"result": {
"id": 211948704,
"first_name": "ربات ادمینهای تلگرام",
"username": "tgAdminsBot"
}
}
Here "result"
is a single object.
This is my class I want to deserialize content to it. I wrote a custom deserializer for TObject
of course:
public class Result
{
private TObject[] result;
private boolean ok;
public void setOk (boolean ok) {//code}
public void setResult (TObject[] result) {//code}
public TObject[] getResult () {//code}
public boolean getOk (){//code}
}
So I assumed in my class that "result"
is an array of TObject
s. Now what can I do? Is using @JsonProperty("result")
for two fields which one is an array of TObject
s and one is a single TObject
OK?
If not what else can I do?
If you enable DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY
both
{"result": []}
and
{"result": {}}
can be parsed as
class Result{
List result;
}
Feature that determines whether it is acceptable to coerce non-array (in JSON) values to work with Java collection (arrays, java.util.Collection) types. If enabled, collection deserializers will try to handle non-array values as if they had "implicit" surrounding JSON array. This feature is meant to be used for compatibility/interoperability reasons, to work with packages (such as XML-to-JSON converters) that leave out JSON array in cases where there is just a single element in array. Feature is disabled by default.
Demo how to use it for OP input jsons and POJOs:
ObjectMapper mapper = new ObjectMapper()
mapper.enable(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY);
Result result = mapper.readValue(Result.class;
Can be used with @JsonFormat
above class or field if you don't like mapper version for some reason
@JsonFormat(with = JsonFormat.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY)
PS. Other SO questions about this problem: LINK