array of json objects java

How to create correct JSONArray in Java using JSONObject

stackoverflow.com › questions › 18983185 › how-to-create-correct-jsonarray-in-java-using-jsonobject

Here is some code using java 6 to get you started:

JSONObject jo = new JSONObject();
jo.put("firstName", "John");
jo.put("lastName", "Doe");

JSONArray ja = new JSONArray();
ja.put(jo);

JSONObject mainObj = new JSONObject();
mainObj.put("employees", ja);

Edit: Since there has been a lot of confusion about put vs add here I will attempt to explain the difference. In java 6 org.json.JSONArray contains the put method and in java 7 javax.json contains the add method.

An example of this using the builder pattern in java 7 looks something like this:

JsonObject jo = Json.createObjectBuilder()
  .add("employees", Json.createArrayBuilder()
    .add(Json.createObjectBuilder()
      .add("firstName", "John")
      .add("lastName", "Doe")))
  .build();

Answer from Grammin on Stack Overflow

Stack Overflow

stackoverflow.com › questions › 18983185 › how-to-create-correct-jsonarray-in-java-using-jsonobject

json - How to create correct JSONArray in Java using JSONObject - Stack Overflow

Top answer

1 of 4

282

Here is some code using java 6 to get you started:

JSONObject jo = new JSONObject();
jo.put("firstName", "John");
jo.put("lastName", "Doe");

JSONArray ja = new JSONArray();
ja.put(jo);

JSONObject mainObj = new JSONObject();
mainObj.put("employees", ja);

Edit: Since there has been a lot of confusion about put vs add here I will attempt to explain the difference. In java 6 org.json.JSONArray contains the put method and in java 7 javax.json contains the add method.

An example of this using the builder pattern in java 7 looks something like this:

JsonObject jo = Json.createObjectBuilder()
  .add("employees", Json.createArrayBuilder()
    .add(Json.createObjectBuilder()
      .add("firstName", "John")
      .add("lastName", "Doe")))
  .build();

2 of 4

18

I suppose you're getting this JSON from a server or a file, and you want to create a JSONArray object out of it.

String strJSON = ""; // your string goes here
JSONArray jArray = (JSONArray) new JSONTokener(strJSON).nextValue();
// once you get the array, you may check items like
JSONOBject jObject = jArray.getJSONObject(0);

Hope this helps :)

Oracle

docs.oracle.com › javaee › 7 › api › javax › json › JsonArray.html

JsonArray (Java(TM) EE 7 Specification APIs)

JsonArray represents an immutable JSON array (an ordered sequence of zero or more values). It also provides an unmodifiable list view of the values in the array. A JsonArray object can be created by reading JSON data from an input source or it can be built from scratch using an array builder object.

Discussions

java - How to get array from JSON Object? - Stack Overflow

i want to get the array of json objects from a json object. But it doesnt work. Can anybody help me? The output is: Exception in thread "main" org.json.JSONException: JSONObject["value"] not fo... More on stackoverflow.com

stackoverflow.com

How to turn json objects into an array of json objects using Java?

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r/javahelp

7

4

June 28, 2022

Jackson parsing JSON containing an array of objects and array of maps w/ dynamic keys

I believe Jackson will be able to deserialize this into a Map field... public class MyCustomClass { @JsonProperty("users") public LinkedHashMap users; @JsonProperty("jobs") public ArrayList jobs; } Depending on the configuration of your objectmapper, you probably don't even need the JsonProperty annotations More on reddit.com

r/androiddev

5

July 22, 2013

streaming a large json object to a file to avoid memory allocation error

Well, JSON.stringify and JSON.parse are synchronous methods that unfortunately you can't pipe to and from. Like u/nissen2 suggests, you'll find some modules out there that will provide you what you're looking for.

Ah, I think I got it. Is there a way to permanently increase the amount of memory that node has access to? Thx.

While this may solve your problem in the mean time, I wouldn't suggest simply allocating more memory (especially with a huge JSON object.)

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