Introduction to JSON

JSON (JavaScript Object Notation) is most widely used data format for data interchange on the web. This data interchange can happen between two computers applications at different geographical locations or running within same hardware machine.

The good thing is that JSON is a human and machine readable format. So while applications/libraries can parse the JSON data – humans can also look at data and derive meaning from it.

A JSON document may contains text, curly braces, square brackets, colons, commas, double quotes, and maybe a few other characters.

Primarily, JSON is built on two structures:

A collection of name/value pairs. In various languages, this is realized as an object, record, struct, dictionary, hash table, keyed list, or associative array.
An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence.

JSON Example
A sample JSON document looks like this:

//JSON Object

{  
    "employee": {  
        "id":           1,
        "name":         "Admin",   
        "location":     "USA"
    }  
}

//JSON Array

{  
    "employees": [
                 {  
                    "id":           1,
                    "name":         "Admin",   
                    "location":     "USA"
                 },
                 {  
                    "id":           2,
                    "name":         "User",   
                    "location":     "USA"
                 },
                 {  
                    "id":           3,
                    "name":         "User2",   
                    "location":     "USA"
                 }
    ]  
}

As you can see, JSON data consists of name/value pairs. These name/value pairs reflect the structure of the data.

Learn JSON
In this tutorial, we will learn various concepts about JSON with examples. Such as:

Difference with XML
Syntax and data types
How to read JSON data
How to write JSON data
Convert JSON to String and vice-versa etc.