conversion of array list to json object string
66,922
Solution 1
To convert ArrayList to Json, just download Open Source json utility from: http://json.org/java/ or Jar file from here
And just do:
JSONArray jsonAraay = new JSONArray(your_array_list);
That's it
Note: You should have setter/getter in your POJO/MODEL class to convert arraylist to json
Solution 2
Don't bother with org.json, use Jackson all the way:
// list is a List<MyData>
final ObjectMapper mapper = new ObjectMapper();
final Map<String, MyData> map = new HashMap<>();
for (final MyData data: list)
map.put(data.fname, data);
final JsonNode json = mapper.valueToTree(map);
Author by
pret
Updated on October 14, 2020Comments
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pret over 3 years
I have a model class method which returns a list of objects which contains all the registered user details. I want to fetch the list resturned by all() method and convert the data into JSON object and pass it to the view like a string. How can I do this conversion of this array list to JSON object?
I was unable to do this by below:
ObjectMapper mapper = new ObjectMapper(); JSONObject json = new JSONObject(); JsonNodeFactory jsonnode = JsonNodeFactory.instance; ObjectNode result = new ObjectNode(jsonnode); for (int i = 0; i < list.size(); i++) { json.put(list.get(i).fname, list.get(i)); System.out.println(json.get("fname")); } @Entity class Mydata extends Model { @Id public Long Id; public String fname; public String lname; public String city; public String state; /****************** READ/select OPERATION *****************/ public static Finder < Long, Mydata > finder = new Finder(Long.class, Mydata.class); public static List < Mydata > all() { return finder.all(); } public static void createuser(Mydata user) { user.save(); } }