How to convert Map into javax.json.JsonObject?

Question

I can do so:

Map<String, String> mapA = ...;
Map<String, String> mapB = mapA.entrySet().stream()
    .collect(Collectors.toMap(
        Map.Entry::getKey,
        Map.Entry::getValue
    ));

But when I'm trying to do this:

... mapA.entrySet().stream()
    .collect(JsonCollectors.toJsonObject(
        JsonObject.Entry::getKey,
        JsonObject.Entry::getValue
    ));

I get

non-static method cannot be referenced from a static context

for the JsonObject.Entry::getKey, JsonObject.Entry::getValue part.

Why's that?

The JSON object will be part of an `application/json` HTTP response. — tom, Sep 22 '19 at 03:21
In what context? Every platform I know of (Spring, Micronaut, Dropwizard, Jersey) supports returning a regular object and does all of this automatically for you. — chrylis -cautiouslyoptimistic-, Sep 22 '19 at 23:13

score 6 · Accepted Answer · answered Sep 22 '19 at 03:24

6

You can use the add method of JsonObjectBuilder:

JsonObjectBuilder builder = Json.createObjectBuilder();
mapA.forEach(builder::add);
JsonObject obj = builder.build();

answered Sep 22 '19 at 03:24

VGR

40,506
4
48
63

That's the simplest solution I think. – tom Sep 22 '19 at 04:52

score 2 · Answer 2 · answered Sep 22 '19 at 03:41

2

javax.json.JsonObject is child class of Map<String,JsonValue> so it has putAll method

void putAll(Map<? extends K,? extends V> m)

So you can just create JsonObject and add the Map

JsonObject object = Json.createObjectBuilder().build();
object.putAll(mapA);

answered Sep 22 '19 at 03:41

Ryuzaki L

37,302
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Thanks, I tried it and it works, but the map has to be ``. – tom Sep 22 '19 at 04:51

score 0 · Answer 3 · answered Sep 22 '19 at 03:25

0

Instead of javax.json use org.json

// Create a JSON object directly from your map
JSONObject obj = new JSONObject( srcmap );
// Convert it into string
String data = obj.toString();

answered Sep 22 '19 at 03:25

Pd Unique

26
6

1

Thanks, org.json is very neat, however javax.json is already used everywhere in the application, I have no way of replacing it. – tom Sep 22 '19 at 03:38
you can try my answer @tom – Ryuzaki L Sep 22 '19 at 03:50

How to convert Map into javax.json.JsonObject?

3 Answers3