how to serialize String/null as json in quarkus?

Question

quarkus serialize String as plain string, null as empty body(with http code 204)

"foo" -> foo

null -> (empty body)

how to make it serialize String and null as json like:

"foo" -> "foo"

null -> null

What response content type do you set? I suspect you set nothing or text/plain. If so, try explicitly setting it to application/json. This should fix "foo" -> "foo" problem, but I'm afraid the null will still be 204. — Nikos Paraskevopoulos, Feb 28 '21 at 20:49

score -1 · Answer 1 · answered Mar 01 '21 at 07:00

You could try somhthing like this:

package org.acme.config;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

@Path("/greeting")
public class GreetingResource {

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public String greetirng() {
        return "{\"greeting\": \"Hello, JSON\", \"penalty\": null}";
    }
        
}

Check it:

$ curl localhost:8080/greeting
{"greeting": "Hello, JSON", "penalty": null}

score -1 · Answer 2 · answered Apr 16 '22 at 06:25

You should use the ObjectMapper class for serializing/deserialising process in Quarkus.

ObjectMapper provides functionality for reading and writing JSON, either to and from basic POJOs (Plain Old Java Objects)

First, you must be sure the io.quarkus:quarkus-jackson package exists in your build.gradle file. If it doesn't exist you can install it with this command:

./gradlew addExtension --extensions="io.quarkus:quarkus-jackson"

After that, you must get an instance: ObjectMapper objectMapper = new ObjectMapper();

You will find your need in this instance of ObjectMapper.

how to serialize String/null as json in quarkus?

2 Answers2