Json Format
JSON (JavaScript Object Notation, pronounced /ˈdʒeɪsən/; also /ˈdʒeɪˌsɒn/) is an open standard file format and data interchange format that uses human-readable text to store and transmit data objects consisting of attribute–value pairs and arrays (or other serializable values). … JSON file names use the extension .json .
Why use JSON
Here are the important benefits/ pros of using JSON:
History of JSON
Here are important landmarks that form the history of JSON:
Features of JSON
Easy to use – JSON API offers high-level facade, which helps you to simplify commonly used use-cases.
Performance – JSON is quite fast as it consumes very less memory space, which is especially suitable for large object graphs or systems.
Free tool – JSON library is open source and free to use.
Doesn’t require to create mapping – Jackson API provides default mapping for many objects to be serialized.
Clean JSON – Creates clean, and compatible JSON result that is easy to read.
Dependency – JSON library does not require any other library for processing.
Rules for JSON syntax are:
Data Types in JSON
Important data type used in JSON are:
| Data Type | Description |
| Number | It includes real number, integer or a floating number |
| String | It consists of any text or Unicode double-quoted with backslash escapement |
| Boolean | The Boolean data type represents either True or False values |
| Null | The Null value denotes that the associated variable doesn’t have any value |
| Object | It is a collection of key-value pairs and always separated by a comma and enclosed in curly brackets. |
| Array | It is an ordered sequence of values separated. |
Number:
Following table displays number types:
| Type | Description |
| Integer | Number 1-9, and 0. Both positive and negative numbers. |
| Fraction | Fractions like 3 |
| Exponent | Exponent like e, e+ |
Syntax:
var json-object-name = { string : number_value,……}
Example:
var obj = {salary: 2600}
It is a series of double-quoted Unicode characters and having backslash escaping.
The following table shows various string types:
| Type | Description |
| * | Use for double quotation typing |
| / | Use for solidus |
| \ | Use for reverse solidus |
| B | Use to add backspace |
| F | From feed |
| N | To create a new line |
| R | Use for carriage return |
| T | To show horizontal tab |
| U | Hexadecimal digits |
Syntax:
var json-object-name = { string : “string value”,…..}
Example:
var obj= {name: ‘Andy’}
It stores only true or false values.
Syntax:
var json-object-name = {string : true/false, …..}
Example:
var obj = {active: ‘true’}
Syntax:
[value, …….]
Example:
Showing an array storing multiple objects:
{
“eBooks”:[
{
“language”:”Pascal”,
“edition”:”third”
},
{
“language”:”Python”,
“edition”:”four”
},
{
“language”:”SQL”,
“edition”:”second”
}
]
}
A JSON Object is an entity in JSON which is enclosed in curly brackets. It is written in the unordered set of name and value pairs in which the name should be followed by “:” (colon), and the name/value pairs need to be separated using “,” (comma). It can be used when key names are arbitrary strings.
Syntax:
{ string : value, ….. }
Example:
{
“id”: 110,
“language”: “Python”,
“price”: 1900,
}
You can insert whitespace between a pair of tokens.
Example:
Syntax:
{string:” “,….}
Example:
var a = ” Alex”; var b = “Steve”;
The given code example defines how to use JSON to store information related to programming books along with edition and author name.
{
“book”:[
{
“id”:”444″,
“language”:”C”,
“edition”:”First”,
“author”:”Dennis Ritchie “
},
{
“id”:”555″,
“language”:”C++”,
“edition”:”second”,
“author”:” Bjarne Stroustrup “
}
]
}
Lets understand JSON format with another JSON file example. Here, JSON defines the first name, last name and id of a student.
{
“student”: [
{
“id”:”01″,
“name”: “Tom”,
“lastname”: “Price”
},
{
“id”:”02″,
“name”: “Nick”,
“lastname”: “Thameson”
}
]
}
Here are some common applications of JSON:
Here is the prime difference between JSON vs. XML
| JSON | XML |
| JSON object has a type | XML data is typeless |
| JSON types: string, number, array, Boolean | All XML data should be string |
| Data is readily accessible as JSON objects | XML data needs to be parsed. |
| JSON files are more human-readable. | XML files are less human-readable. |
| JSON is supported by most browsers. | Cross-browser XML parsing can be tricky |
| JSON has no display capabilities. | XML provides a capability to display data because it is a markup language. |
| Retrieving value is easy | Retrieving value is difficult |
| Supported by many Ajax toolkit | Not fully supported by Ajax toolkit |
| A fully automated way of deserializing/serializing JavaScript. | Developers have to write JavaScript code to serialize/deserialize from XML |
| Native support for objects. | The object has to be expressed by conventions – mostly missed use of attributes and elements. |
Below is a simple JSON example:
{
“student”: [
{
“id”:”01″,
“name”: “Tom”,
“lastname”: “Price”
},
{
“id”:”02″,
“name”: “Nick”,
“lastname”: “Thameson”
}
]
}
<?xml version=”1.0″ encoding=”UTF-8″ ?>
<root>
<student>
<id>01</id>
<name>Tom</name>
<lastname>Price</lastname>
</student>
<student>
<id>02</id>
<name>Nick</name>
<lastname>Thameson</lastname>
</student>
</root>
Here are few advantages of JSON:
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