JSON Java Script Object Notation Copyright © 2013 Curt Hill.

JSONJava Script

Object NotationCopyright © 2013 Curt Hill

What is it?• Language for data interchange

– Derived from JavaScript (ECMA standard)

– Alternative to XML in that respect

• Both easy for people to read and easy for machines to parse

• Consists of sequences and attribute-value pairs

• It is an open standard

Copyright © 2013 Curt Hill

Simple Types• Does not have many• Number

– A floating point type

• String– Enclosed in double quotes– Uses UNICODE characters

• Boolean– May be true or false

• null– Indicates an empty value


Structured Types• Only two structuring types• Object

– Similar to a group, record, or struct, depending on language

– Unordered, comma separated list of name value pairs enclosed in braces

– The key is separated from the value by a colon

• Array– An ordered, comma separated list of

values enclosed in bracketsCopyright © 2013 Curt Hill

Commentary• White space may be interspersed

for readability without changing meaning

• Hardly any programming language lacks these features– Most have a JSON interface

• Keys are merely strings


Example• A simple object to contain a name:

{ “first”:”Bill”, “lastname”: “Smith” }• An array of names inside an object:{ “employees” : [{“first”:”Bill”, “last”:“Sam” },{“first”:”John”, “last”:“Doe” },{“first”:”Curt”, “last”:“Hill” }] }


Example 2• An array of objects that describe a

products:{“products [ { “name”: “Widget”, “price”:24.91}, { “name”: “Gizmo”, “price”:2.28},{ “name”: “Junk”, “price”:6} ] }


BSON• Binary JSON also exists• This is a binary encoded

serialization of JSON objects• These should be more compact

and faster to parse


JSON Java Script Object Notation Copyright © 2013 Curt Hill.

Documents

Transcript of JSON Java Script Object Notation Copyright © 2013 Curt Hill.