Do JSON in One line with Jackson + Java

Goal: To list some one line code from jackson

Mansura H.

·

Follow

1 min read

·

Sep 26, 2016

--

Listen

Share

Get field by FieldPath

JsonNode result =jsonobject.at("/students/subjects/english/result");

Convert List to ArrayNode

ArrayNode arrayNode = new ObjectMapper().convertValue(docs, ArrayNode.class);

Find all values in a list for a key in all nested Json object

/*  If the json document (json) is as following [{
 "id": "NL",
 "document": {
  "Country": {
   "label": "Netherlands",
   "code": "NL",
   "translations": [{
    "languagecode": "en",
    "label": "Netherlands"
   },
   {
    "languagecode": "de",
    "label": "Niederlande"
   },
   {
    "languagecode": "es",
    "label": "Países Bajos"
   },
   {
    "languagecode": "fr",
    "label": "Pays-Bas"
   },
   {
    "languagecode": "ja",
    "label": "オランダ"
   },
   {
    "languagecode": "it",
    "label": "Paesi Bassi"
   }]
  }
 }
},
{
 "id": "AN",
 "document": {
  "Country": {
   "label": "Netherlands Antilles",
   "code": "AN",
   "translations": []
  }
 }
},
{
 "id": "NET",
 "document": {
  "Skill": {
   "referenceId": "02",
   "label": ".NET",
   "code": "02",
   "category": "Software Development"
  }
 }
}];*/
List<JsonNode> labels = json.findValues("labels");/*** The output labels will be  as foolowing ***/["Netherlands", "Netherlands", "Niederlande", "Países Bajos", "Pays-Bas", "オランダ", "Paesi Bassi", "Netherlands Antilles", ".NET"]

Iterate by Key

Iterator<Entry<String, JsonNode>> p = jsonNode.fields();

Convert JsonNode to key-value Map

CollectionType mapCollectionType = new ObjectMapper().getTypeFactory().constructCollectionType(List.class, Map.class);try {
List<Map<String, String>> map = new ObjectMapper().readValue(jsonnode.toString(), mapCollectionType);} catch (Exception e) {  
   e.printStackTrace();
}

Find Parent Node

JsonNode parent = jsonNode.findParent("fieldsName");

Read from Stream

JsonNode node= new ObjectMapper().readTree(inputstream);

Write to File

File file = new File("nodes.json");
PrintWriter fileWriter = new PrintWriter(new BufferedWriter(new FileWriter(file, true)));
ObjectMapper mapper = new ObjectMapper();fileWriter.write(mapper.writeValueAsString(node));
fileWriter.close();