How to sort JsonNode array List

Question

I am trying to sort below array node within my json payload. Should be sort by name element

Before:

"empData": [
    {
      "name": "Jhon",
      "age": 33
    },
    {
      "name": "Sam",
      "age": 24
    },
    {
      "name": "Mike",
      "age": 65
    },
    {
      "name": "Jenny",
      "age": 33
    }
  ]

Expected:

"empData": [
    {
      "name": "Jenny",
      "age": 33
    },
    {
      "name": "Jhon",
      "age": 33
    },
    {
      "name": "Mike",
      "age": 65
    },
    {
      "name": "Sam",
      "age": 24
    }
  ]

I was trying below option:

private static final ObjectMapper SORTED_MAPPER = new ObjectMapper();

static {
    SORTED_MAPPER.configure(SerializationFeature.ORDER_MAP_ENTRIES_BY_KEYS, true);
}

public static JsonNode sortJsonArrayList(final JsonNode node) throws IOException {
    final Object obj = SORTED_MAPPER.treeToValue(node, Object.class);
    final String json = SORTED_MAPPER.writeValueAsString(obj);
    return objectMapper.readTree(json);
}

But not sure how to select name key for sorting.

Grigorii Riabov · Accepted Answer · 2021-04-28 09:01:55Z

3

Try something like this:

public JsonNode some(JsonNode node){
        //find list of objects that contains field name
        List<JsonNode> dataNodes = node.findParents("name");
        //sort it
        List<JsonNode> sortedDataNodes = empDataNodes
                .stream()
                .sorted(Comparator.comparing(o -> o.get("name").asText()))
                .collect(Collectors.toList());
        //return the same Json structure as in method parameter
        ArrayNode arrayNode = objectMapper.createObjectNode().arrayNode().addAll(sortedEmpDataNodes);
        return objectMapper.createObjectNode().set("empData", arrayNode);
}

You can debug it step by step and see how it works.

answered Apr 28, 2021 at 9:01

Grigorii Riabov

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3 Comments

Shabar Over a year ago

Can we have same approach to sort with two keys?

Grigorii Riabov Over a year ago

You can check this answer and add some of it solution in .sorted() method

Shabar Over a year ago

Thanks. found stackoverflow.com/a/8036545/2303693 also which does the work perfectly

Serhii Vasniev · Accepted Answer · 2021-04-28 08:24:02Z

2

ORDER_MAP_ENTRIES_BY_KEYS is the feature which enables Map sorting by Map keys. As your result type is not a Map this sorting will not be applied. To sort array you can create custom deserialiser or sort deserialised array in place. This answer describes how this can be achieved.

edited Apr 28, 2021 at 8:24

answered Apr 28, 2021 at 8:13

Serhii Vasniev

7935 silver badges18 bronze badges

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