How to parse a JSON string into JsonNode in Jackson?

user_368760 0
Viewed 340052

It should be so simple, but I just cannot find it after being trying for an hour.

I need to get a JSON string, for example, {"k1":v1,"k2":v2}, parsed as a JsonNode.

JsonFactory factory = new JsonFactory();
JsonParser jp = factory.createJsonParser("{\"k1\":\"v1\"}");
JsonNode actualObj = jp.readValueAsTree();

gives

java.lang.IllegalStateException: No ObjectCodec defined for the parser, can not deserialize JSON into JsonNode tree

jackson parsing json java
6 Answers

A slight variation on Richards answer but readTree can take a string so you can simplify it to:

ObjectMapper mapper = new ObjectMapper();
JsonNode actualObj = mapper.readTree("{\"k1\":\"v1\"}");
slashnick_210300

New approach to old question. A solution that works from java 9+

ObjectNode agencyNode = new ObjectMapper().valueToTree(Map.of("key", "value"));

is more readable and maintainable for complex objects. Ej

Map<String, Object> agencyMap = Map.of(
        "name", "Agencia Prueba",
        "phone1", "1198788373",
        "address", "Larrea 45 e/ calligaris y paris",
        "number", 267,
        "enable", true,
        "location", Map.of("id", 54),
        "responsible", Set.of(Map.of("id", 405)),
        "sellers", List.of(Map.of("id", 605))
);
ObjectNode agencyNode = new ObjectMapper().valueToTree(agencyMap);
user_47279910
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