An Introduction To JSON

Introduction to JSON

In this article we will discuss the first two points from the following. In upcoming articles, I will discuss how to create a JSON file from database table.

• Introduction to JSON
• JSON syntax
• Parsing and Generating JSON files
• JSON data storage application

So let us start with the introduction part.

What is JSON?

JSON (JavaScipt Object Notation) is a lightweight data-interchange format.

Why use it

• Same syntax as JavaScript objects.
• Easy for humans to read and write.
• Language independent.
• Can be used to store application data.

How can we create /read JSON file

We can create/read JSON file by using:

• JavaScriptSerializer (inbuilt in dotnet framework).
• JSON.NET third party tool (download from Nuget package Manager).

So let us look at JSON:

{ } culry braces represent object
key – value pair

JSON Syntax

So what exactly makes up a JSON file:

• Values
• Objects
• Arrays
• Putting it all together

JSON Values can be:

• Strings ( in double quotes)
• Numbers (integer or floating point)
• Boolean ( true or false )
• Objects ( in curly brackets)
• Array( in square brackets)
• Null

JSON Object

• Name/value pairs using colons
• Enclose by curly braces
• Pairs separated by commas

Example

{
   name: values,
   name2: values2
}

So here is a very simple example curly braces representing json object, name values pair separated by comma:

{
   "Name" :"Ravi",
   "City": "Varanasi",
}

More complex example

{
   "countryId": 1,
   "countryName" : "India",
   "state" : ["uttar pradesh","Mumbai","Bangalore"]
}

Again we have curly braces representing object. This time we have three name value pairs: countryId is just integer, countryName is string and state is arrays shown by bracket,

JSON Arrays

• Values enclosed by brackets
• Seprated by commas [item,item,item,item]

Example

["uttar pradesh","Mumbai","Bangalore"]

Indicated by bracket we have json arrays and in this example its an array of three string and each string separated by commas:

[1,2,3,4] its array of number

Complex array

[
{
    "AlbumId": 3,
    "GenreId": 1,
    "ArtistId": 4,
},
{
    "AlbumId": 5,
    "GenreId": 1,
    "ArtistId": 77,
}]

So array can be collection of anything including object and these object have three name value pair.

Putting it all together,

 

• JSON values can also be objects or arrays
• JSON objects and arrays can be nested

Points of Interest

• In this article, I have touched very basic of JSON.
• JSON is very useful in client server communication where network bandwidth is very limited.