Issue
I have an enum defined as:
public static enum State {
@JsonProperty("At Rest")
AT_REST,
@JsonProperty("In Motion")
IN_MOTION,
@JsonProperty("Stalled")
STALLED;
}
So, the server produces "At Rest" when Jackson serializes the AT_REST enum into JSON. Similarly, Jackson deserializes "At Rest" into AT_REST when the client passes JSON to the server. For example:
@GetMapping()
public State[] getAllStates() {
return State.values(); //returns JSON ["At Rest", "In Motion", "Stalled"]
}
@PostMapping()
public void saveState(@ResponseBody State state /*when client sends "At Rest", it gets converted into Enum*/) {
//save state
}
I also have a search GET endpoint. The client calls it with a "state" query parameter such https://localhost/search?state=At Rest. Since the query parameter value is not JSON, I have a Spring converter:
@Component
public class StringToStateConverter implements Converter<String, State> {
@Override
public State convert(String description) {
if ("At Rest".equals(description)) {
return State.AT_REST;
} else if ("In Motion".equals(description)) {
return State.IN_MOTION;
} else if ("Stalled".equals(description)) {
return State.STALLED;
} else {
return null;
}
}
}
Is it possible to have Spring use JsonProperty when deserializing a query param? If not, how can I avoid having the String description in multiple places in my code? I prefer not to make a description field in the enum since this is really just for client display.
Solution
Is it possible to have Spring use JsonProperty when deserializing a query param?
Yes.
@Component
@RequiredArgsConstructor
public class StringToStateConverter implements Converter<String, State> {
private final ObjectMapper mapper;
@Override
public State convert(String description) {
try {
return mapper.readValue("\"" + description + "\"", State.class);
} catch (JsonProcessingException e) {
// code to return error to client
}
}
Answered By - James
Answer Checked By - Mary Flores (JavaFixing Volunteer)
