JSONObject JSON array length

Question

I am reading the below XML in java, and converting to JSONObject [org.json.JSONObject]. and appending the metadata and returning as JSON.

Problem: JSONObject jsonObj = service.getMyData(); // custom methods and invocation

int count = jsonObj.length(); // length is 1

How do I take the correct count from this jsonObj? . The correct count I am referring to is 2 in this case. [2 books]

What I tried?

(1) System.out.println(jsonObj.length()); // prints 1

API says: length() Get the number of keys stored in the JSONObject.

(2) Since number of keys is returned as 1, there is no point on trying the below one, still I tried and got the error of org.json.JSONException: JSONObject["User"] not found.

 System.out.println(jsonObj.getJSONArray("User").length());

(3) IF I try 'Users' ie: jsonObj.getJSONArray("Users").length() , it says JSONObject["Users"] is not a JSONArray.

(4)

JSONObject jsonObj = service.getMyData();
 JSONObject jUsers =  jsonObj.getJSONObject("Users");
 JSONObject jUser =  jUsers.getJSONObject("User");
 System.out.println(jUser.length());

Error: org.json.JSONException: JSONObject["User"] is not a JSONObject.

---

XML:

<Users>
    <User>
        <Name>Unni</Name>
        <Books>
            <Book>book1</Book>
            <Book>book2</Book>
            <Book>book3</Book>
        </Books>
    </User>
    <User>
        <Name>Ammu</Name>
        <Books>
            <Book>book1</Book>
            <Book>book2</Book>
            <Book>book4</Book>
        </Books>
    </User>
</Users>

JSON:

{
    "Users": {
        "User": [
            {
                "Name": "Unni",
                "Books": {
                    "Book": [
                        "book1",
                        "book2",
                        "book3"
                    ]
                }
            },
            {
                "Name": "Ammu",
                "Books": {
                    "Book": [
                        "book1",
                        "book2",
                        "book4"
                    ]
                }
            }
        ]
    }
}

Solution 1

In JSON format,

[] is JSONArray

{} is JSONObject

In your post,

• Users - JSONObject
• User - JSONArray
• Books - JSONObject
• Book - JSONArray

---

Error: org.json.JSONException: JSONObject["User"] is not a JSONObject.

As mentioned above, try with getJSONArray()

 JSONArray userArray = jUsers.getJSONArray("User");

Solution 2

I had to call the getJSONArray method when retrieving the array.

JSONObject jsonObj = service.getMyData();
JSONObject jUsers =  jsonObj.getJSONObject("Users");
System.out.println(jUsers.getJSONArray("User").length());