How to update only Non Null Json fields of a Object in an Existing Json Object in Android

Question

Suppose, we have a User JSON response:

{
    "name": "Jack",
    "age": 28,
    "address": "Some address",
    "occupation": "Employee",
    "gender":"male"
}

With some network calls, we got another JSON response:

{ "age":"27", "address":"Some new address" }

Now, the requirement is to update the existing object with the updated fields. For e.g:

{
    "name": "Jack",
    "age":"27",
    "address":"Some new address",
    "occupation": "Employee",
    "gender":"male"
}

Notice that age and address was changed. This can be done by making null checks for small user object but doesn't look smart enough for some object like Product that will have more than 100 fields.

Looking for an efficient way to do it in Java/Kotlin.

Possible duplicate of How to join two JavaScript Objects, without using JQUERY — Ctznkane525
– Ctznkane525, Commented Apr 10, 2019 at 19:56
Possible duplicate of Helper in order to copy non null properties from object to another ? (Java) — Michał Ziober
– Michał Ziober, Commented Apr 10, 2019 at 20:19

Alexander Gapanowich · Accepted Answer · 2019-04-10 20:34:24Z

1

You can use a HashMap for it, let the value name be a key, and the value will be a value ))) :

HashMap<String, String> hashMap = new HashMap<String, String>(); 


    hashMap.put("name", "Jack"); 
    hashMap.put( "age", "27");

Now, if you need to update values, just add it with the same key:

 hashMap.put( "age", "67");

Now you just need to iterate through your hashMap and get all values back, it could be like this:

 Iterator it = hashMap.entrySet().iterator();
 while (it.hasNext()) {
    Map.Entry pair = (Map.Entry)it.next();
    System.out.println(pair.getKey() + " = " + pair.getValue());
    it.remove();
 }

And no dataBase, as you can see )))

answered Apr 10, 2019 at 20:34

Alexander Gapanowich

5922 silver badges8 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Kevin Coppock · Accepted Answer · 2019-04-10 20:37:01Z

1

A JSONObject is essentially just a map of keys/values. Assuming you only care about one level deep, a trivial approach here would be to just map the key/values from the second object (where the values are not null) to the current object.

This could be defined as an extension function on JSONObject, such as:

fun JSONObject.mergeWith(other: JSONObject): JSONObject = apply {
    other.keys()
        .asSequence()
        .associateWith(other::get)
        .filterValues { it != null }
        .forEach { (key, value) -> this.put(key, value) }
}

For example:

val firstJson = JSONObject().apply {
    put("x", 1)
    put("y", "1")
}

val secondJson = JSONObject().apply {
    put("x", 2)
    put("y", null)
}

val mergedJson = firstJson.mergeWith(secondJson) // contains x = 2, y = "1"

answered Apr 10, 2019 at 20:37

Kevin Coppock

135k45 gold badges270 silver badges279 bronze badges

2 Comments

codepeaker Over a year ago

Plus 1 Seems fine but I have to convert JSONObject to User object which I think is a overhead.

codepeaker Over a year ago

Alternatively I converted the class members to field array and merged both the object with null check.

Collectives™ on Stack Overflow

How to update only Non Null Json fields of a Object in an Existing Json Object in Android

2 Answers 2

Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related