How to return Java 'java.time.Instant' property as json value in Restful API body response?

Question

I have a Spring Boot restful API service that returns a Java object in its response which is translated into json.

One of the Java object properties is a 'Java.time.Instant'. How should I translate this for the json object being returned?

update

I've tried using @JsonFormat but this doesn't work...

The Java object being returned has an 'Instant' property...

 @JsonFormat(shape=JsonFormat.Shape.STRING, pattern="yyyy-MM-dd'T'HH:mm:ss.SSSZ",timezone = "UTC")
 public Instant getRequested() {
     return Requested;
}

This is coming back in the json response body as...

"requested": {
    "epochSecond": 1499342121,
    "nano": 868000000
},

I'm using Spring Boot 1.5.4

The controller method is...

@RequestMapping(value="/", method= RequestMethod.POST)
public AcceptedAccountRequest newRequest(@RequestBody NewAccountRequest aRequest) {
AcceptedAccountRequest anAcceptedRequest = createAccepted(aRequest);
return anAcceptedRequest;
}

Nonconformity

You can use .toEpochMilli which gets a long value. Then returning it back to Instant is more easier with .ofEpochMilli – Dyson

Reading further on this, the general sentiment seems to be to have all json timestamp properties returned using the 8601 format. Is use of the '@jsonformat' annotation the right way to serve this? – Nonconformity

java.time.Instant has ISO-8601 as string representation, a swift look into the API doc also would've revealed this - so as long as you're not using some weird, reflection-based serialization you're good to go. Please use google. – Bolshevik

I've tried adding @JsonFormat but the json being generated doesn't recognise ths... – Nonconformity

Answer 1

Solved it... I was mising theh jsr310 maven dependency

<dependency>
  <groupId>com.fasterxml.jackson.datatype</groupId>
  <artifactId>jackson-datatype-jsr310</artifactId>
</dependency>

On clarification... if I want all Instant properties to be returned in json as UTC should i use the following format instruction, or is there another better way of doing this...

@JsonFormat(shape=JsonFormat.Shape.STRING, pattern="yyyy-MM-dd'T'HH:mm:ss.SSSZ",timezone = "UTC")

Nonconformity

There is a better way - add the following to your application.properties: spring.jackson.serialization.write_dates_as_timestamps=false – Titivate

Answer 2

1. pom.xml add

   <dependency>
       <groupId>com.fasterxml.jackson.datatype</groupId>
       <artifactId>jackson-datatype-jsr310</artifactId>
   </dependency>
   

2. application.properties add

   spring.jackson.serialization.write-dates-as-timestamps=false
   

link https://codeboje.de/jackson-java-8-datetime-handling/

Loire

Answer 3

You can simply use the java.time.Instant to their representation using .toString() If you are using Spring, you might have to add @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) to your RestMethod in order to make sure it is converted correctly

Leading

I can't get this to work. Whatever annotation I put in the json being returned comes across as ... "validUntil": { "epochSecond": 1499772556, "nano": 656000000 } . – Nonconformity

I'm using Spring Boot 1.5.4 – Nonconformity