json_tutorial.pdf

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JSON or JavaScript Object Notation is a lightweight text-based open standard designed JSON or JavaScript Object Notation is a lightweight text-based open standard designed for human-readable data interchange. The JSON format was originally specified by for human-readable data interchange. The JSON format was originally specified by Douglas Crockford, and is described in RFC 4627. The official Internet media type for Douglas Crockford, and is described in RFC 4627. The official Internet media type for JSON is application/json. The JSON filename extension is .json.

JSON is application/json. The JSON filename extension is .json.

This tutorial will help you understand JSON and its use within various programming This tutorial will help you understand JSON and its use within various programming languages such as PHP, PERL, Python, Ruby, Java, etc.

languages such as PHP, PERL, Python, Ruby, Java, etc.

Audience

This tutorial has been designed to help beginners understand the basic functionality of This tutorial has been designed to help beginners understand the basic functionality of JavaScript Object Notation (JSON) to develop the data interchange format. After JavaScript Object Notation (JSON) to develop the data interchange format. After completing this tutorial, you will have a good understanding of JSON and how to use it completing this tutorial, you will have a good understanding of JSON and how to use it with JavaScript, Ajax, Perl, etc.

with JavaScript, Ajax, Perl, etc.

Prerequisites

Before proceeding with this tutorial, you should have a basic understanding of the web Before proceeding with this tutorial, you should have a basic understanding of the web application

application’s’s_{work over HTTP and we assume that you have a basic knowledge of}_{work over HTTP and we assume that you have a basic knowledge of}

JavaScript. JavaScript.

Copyright & Disclaimer



All the content and graphics published in this e-book are the property of Tutorials Point All the content and graphics published in this e-book are the property of Tutorials Point (I) Pvt. Ltd.

(I) Pvt. Ltd. The user of The user of this e-book is prohibited to this e-book is prohibited to reuse, retain, copy, reuse, retain, copy, distribute ordistribute or republish any contents or a part of contents of this e-book in any manner without written republish any contents or a part of contents of this e-book in any manner without written consent of the publisher.

consent of the publisher.

We strive to update the contents of our website and tutorials as timely and as precisely We strive to update the contents of our website and tutorials as timely and as precisely as possible, however, the contents may contain inaccuracies or errors. Tutorials Point (I) as possible, however, the contents may contain inaccuracies or errors. Tutorials Point (I) Pvt. Ltd. provides no guarantee regarding the accuracy, timeliness or completeness of Pvt. Ltd. provides no guarantee regarding the accuracy, timeliness or completeness of our website or its contents including this tutorial. If you discover any errors on our our website or its contents including this tutorial. If you discover any errors on our website or in this tutorial, please notify us at

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About

About the the Tutorial ... Tutorial ... ii

Audience ... i

Prerequisites ... i

Copyright Copyright & & Disclaimer ... Disclaimer ... ii

Table Table of Contents ... iiof Contents ... ii

Uses of Uses of JSON ... JSON ... 11 Characteristics Characteristics of of JSON JSON ... ... 11 Simple Exam Simple Example in ple in JSON ... JSON ... 11 Number ... 5 Number ... 5 String String ... ... 66 Boolean ... 7 Boolean ... 7 Array ... 7 Array ... 7 Object Object ... ... 88 Whitespace Whitespace ... ... 88 null ... 9 null ... 9 JSON

JSON Value ... Value ... 99

Creating Simple

Creating Simple Objects ... Objects ... 1010 Creating Array

Creating Array Objects ... Objects ... 1111

JSON ─ OVERVIEW JSON ─ OVERVIEW

JSON

JSON ─ ─ SYNT SYNT

JSON

JSON ─ ─ D D T T TYPESTYPES

JSON ─ OBJECTS

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JSON Schema Va

JSON Schema Va lidation Librarlidation Librar ies ... ies ... 1313 JSON Schema

JSON Schema Example ... 14Example ... 14

Environment

Environment ... ... 1818 JSON Functions

JSON Functions ... ... 1818 Encoding JSON in

Encoding JSON in PHP (json_encode) ... PHP (json_encode) ... 1818 Decoding JSON

Decoding JSON in PHP in PHP (json_decode) (json_decode) ... ... 1919

Environment

JSON Functions ... ... 2121 Encoding JSON in Perl

Encoding JSON in Perl (encode_json) ... (encode_json) ... 2222 Decoding JSON

Decoding JSON in Perl in Perl (decode_json) ... (decode_json) ... 2323

Environment

JSON Functions ... ... 2525 Encoding JSON

Encoding JSON in Python in Python (encode) (encode) ... ... 2525 Decoding JSON in

Decoding JSON in Python (decode) Python (decode) ... ... 2626

Environment

Environment ... ... 2727 Parsing JSON

Parsing JSON using Ruby ... 27using Ruby ... 27

JSON

JSON ─ ─ COMP COMP RISON RISON WIWITH TH XML XML 1717

JSON ─ JSON WITH PHP

JSON ─ JSON WITH PHP 1818

JSON ─ JSON WITH PER

JSON ─ JSON WITH PERL L 2121

JSON ─ JSON WITH PYT

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Environment

Environment ... ... 2929 Mapping between

Mapping between JSON and Java JSON and Java entities ... entities ... 2929 Encoding JSON

Encoding JSON in Java ... 30in Java ... 30 Decoding JSON

Decoding JSON in in Java Java ... ... 3131

12

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JSON or JavaScript Object Notation is a lightweight text-based open standard designed JSON or JavaScript Object Notation is a lightweight text-based open standard designed for human-readable data interchange. Conventions used by JSON are known to for human-readable data interchange. Conventions used by JSON are known to programmers, which include C, C++, Java, Python, Perl, etc.

programmers, which include C, C++, Java, Python, Perl, etc.



 _{JSON stands for JavaScript Object Notation.}_{JSON stands for JavaScript Object Notation.} 

 _{The format was specified by Douglas Crockford.}_{The format was specified by Douglas Crockford.} 

 _{It was designed for human-readable data interchange.}_{It was designed for human-readable data interchange.} 

 _{It has been extended from the JavaScript scripting language.}_{It has been extended from the JavaScript scripting language.} 

 _{The filename extension is}_{The filename extension is .json}_.json.. 

 _{JSON Internet Media type is}_{JSON Internet Media type is application/json}_{application/json..} 

 _{The Uniform Type Identifier is public.json.}_{The Uniform Type Identifier is public.json.}

Uses of JSON



 _{It is used while writing JavaScript based applications that includes browser}_{It is used while writing JavaScript based applications that includes browser}

extensions and websites. extensions and websites.



 _{JSON format is used for serializing and transmitting structured data over network}_{JSON format is used for serializing and transmitting structured data over network}

connection. connection.



 _{It is primarily used to transmit data between a}_{It is primarily used to transmit data between a server and web applications.}_{server and web applications.} 

 _{Web services and APIs use JSON format to provide public data.}_{Web services and APIs use JSON format to provide public data.} 

 _{It can be used with modern programming languages.}_{It can be used with modern programming languages.}

Characteristics of JSON



 _{JSON is easy to read and write.}_{JSON is easy to read and write.} 

 _{It is a lightweight text-based interchange format.}_{It is a lightweight text-based interchange format.} 

 _{JSON is language independent.}_{JSON is language independent.}

Simple Example in JSON

The following example shows how to use JSON to store information related to books The following example shows how to use JSON to store information related to books based on their topic and edition.

based on their topic and edition.

{ { "book": [ "book": [ { {

1. JSON

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"id":"01", "id":"01", "language": "Java", "language": "Java", "edition": "third", "edition": "third",

"author": "Herbert Schildt" "author": "Herbert Schildt" }, }, { { "id":"07", "id":"07", "language": "C++", "language": "C++", "edition": "second" "edition": "second" "author":

"author": "E.Balagurusa"E.Balagurusamy"my" }]

}] }

}

After understanding the above program, we will try another example. Let's save the After understanding the above program, we will try another example. Let's save the below code as

below code as json.htm json.htm::

<title>JSON

<title>JSON example</title>example</title> <script language="javascript" > <script language="javascript" >

var object1

var object1 = { "lang= { "language" : "Java", uage" : "Java", "author" "author" : "herbert sc: "herbert schildt" };hildt" }; document.write("<

document.write("<h1>JSON with h1>JSON with JavaScript example</h1>");JavaScript example</h1>"); document.write("<br>");

document.write("<br>"); document.write("<

document.write("<h3>Language = " h3>Language = " + object1.language+"</h3>");+ object1.language+"</h3>"); document.write("<

document.write("<h3>Author = h3>Author = " " + object1.author+"</h3>");+ object1.author+"</h3>");

var object2

var object2 = { "= { "language" : language" : "C++", "au"C++", "author" thor" : "E-Bala: "E-Balagurusamy" };gurusamy" }; document.write("<br>");

document.write("<h3>Language = " h3>Language = " + object2.language+"</h3>");+ object2.language+"</h3>"); document.write("<

document.write("<h3>Author = h3>Author = " " + object2.author+"</h3>");+ object2.author+"</h3>");

document.write("<

document.write("<hr hr />");/>"); document.write(ob

document.write(object2.language + " programming language can be studied " ject2.language + " programming language can be studied " ++ "from book written by "

"from book written by " + object2.author);+ object2.author); document.write("<

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</script> </script> </head> </head> <body> <body> </body> </body> </html> </html>

Now let's try to open

Now let's try to open json.htm json.htm using IE or any other javascript enabled browser thatusing IE or any other javascript enabled browser that produces the following result:

produces the following result:

You can refer to

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Let's have a quick look at the basic syntax of JSON. JSON syntax is basically considered Let's have a quick look at the basic syntax of JSON. JSON syntax is basically considered as a subset of JavaScript syntax; it

as a subset of JavaScript syntax; it includes the following:includes the following:



 _{Data is represented in name/value pairs.}_{Data is represented in name/value pairs.} 

 _{Curly braces hold objects and each name is followed by ':'(colon), the}_{Curly braces hold objects and each name is followed by ':'(colon), the}

name/value pairs are separated by , (comma). name/value pairs are separated by , (comma).



 _{Square brackets hold arrays and values are separated by ,(comma).}_{Square brackets hold arrays and values are separated by ,(comma).}

Below is a simple example: Below is a simple example:

{ { "book": [ "book": [ { { "id":"01", "id":"01", "language": "Java", "language": "Java", "edition": "third", "edition": "third",

"author": "Herbert Schildt" "author": "Herbert Schildt" }, }, { { "id":"07", "id":"07", "language": "C++", "language": "C++", "edition": "second" "edition": "second" "author": "E.Balagurusamy" "author": "E.Balagurusamy" }] }] } }

JSON supports the following two data structures: JSON supports the following two data structures:



 _{Collection of name/value pairs:}_{Collection of name/value pairs: This Data Structure is supported by different}_{This Data Structure is supported by different}

programming languages. programming languages.



 _{Ordered list of values:}_{Ordered list of values: It includes array, list, vector or sequence etc.}_{It includes array, list, vector or sequence etc.}

2. JSON

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JSON format supports the following data types: JSON format supports the following data types:

Type Description

Number

Number double- double- precision precision floating-point floating-point format format in in JavaScriptJavaScript

String

String double-quoted double-quoted Unicode Unicode with with backslash backslash escapingescaping

Boolean

Boolean true true or or falsefalse

Array

Array an an ordered ordered sequence sequence of of valuesvalues

Value

Value it it can can be be a a string, string, a a number, number, true true or or false, false, null null etcetc

Object

Object an an unordered unordered collection collection of of key:value key:value pairspairs

Whitespace

Whitespace can can be be used used between between any any pair pair of of tokenstokens

null empty

Number



 _{It is a double precision floating-point format in JavaScript and it depends on}_{It is a double precision floating-point format in JavaScript and it depends on}

implementation. implementation.



 _{Octal and hexadecimal formats are not used.}_{Octal and hexadecimal formats are not used.} 

 _{No NaN or Infinity is used in Number.}_{No NaN or Infinity is used in Number.}

The following table shows the number types: The following table shows the number types:

Type Description

Integer

Integer Digits Digits 1-9, 1-9, 0 0 and and positive positive or or negativenegative

Fraction

Fraction Fractions Fractions like like .3, .3, .9.9

Exponent

Exponent Exponent Exponent like like e, e, e+, e+, e-,E, e-,E, E+, E+, E-

E-3. JSON

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Syntax

var json-object-name = {"string" : number_value, ...} var json-object-name = {"string" : number_value, ...}

Example

Example showing Number Datatype, value should not be quoted: Example showing Number Datatype, value should not be quoted:

var obj = {"marks": 97} var obj = {"marks": 97}

String



 _{It is a sequence of zero or more double quoted Unicode characters with backslash}_{It is a sequence of zero or more double quoted Unicode characters with backslash}

escaping. escaping.



 _{Character is a single character string i}_{Character is a single character string i .e. a string with length 1.}_{.e. a string with length 1.}

The table shows various special characters that you can use in strings of a JSON The table shows various special characters that you can use in strings of a JSON document:

document:

Type Description

"

" double double quotationquotation

\ backslash

/

/ forward slashforward slash

b backspace

f

f form form feedfeed

n

n new new lineline

r

r carriage carriage returnreturn

t

t horizontal horizontal tabtab

u

u four four hexadecimal hexadecimal digitsdigits

Syntax

var json-object-name = { string

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Example

Example showing String Datatype: Example showing String Datatype:

var obj = {"name": "Amit"} var obj = {"name": "Amit"}

Boolean

It includes true or false values. It includes true or false values.

Syntax

var json-object-name = { string

var json-object-name = { string : true/false, ...}: true/false, ...}

Example

var obj =

var obj = {"name": "Amit", "marks": 97, "distinction": true}{"name": "Amit", "marks": 97, "distinction": true}

Array



 _{It is an ordered collection of values.}_{It is an ordered collection of values.} 

 _{These are enclosed in square brackets which means that array begins with .[. and}_{These are enclosed in square brackets which means that array begins with .[. and}

ends with .].. ends with .]..



 _{The values are separated by , (comma).}_{The values are separated by , (comma).} 

 _{Array indexing can be started at 0 or 1.}_{Array indexing can be started at 0 or 1.} 

 _{Arrays should be used when the key names are sequential integers.}_{Arrays should be used when the key names are sequential integers.}

Syntax

[ value, ...] [ value, ...]

Example

Example showing array containing multiple objects: Example showing array containing multiple objects:

{ { "books": [ "books": [ { "language":"Java" , "edition":"second" }, { "language":"Java" , "edition":"second" }, { "language":"C++" , "lastName":"fifth" }, { "language":"C++" , "lastName":"fifth" }, { "language":"C" , "lastName":"third" } { "language":"C" , "lastName":"third" } ] ] } }

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Object



 _{It is an unordered set of name/value pairs.}_{It is an unordered set of name/value pairs.} 

 _{Objects are enclosed in curly braces that is, it starts with '{' and ends with '}'.}_{Objects are enclosed in curly braces that is, it starts with '{' and ends with '}'.} 

 _{Each name is followed by ':'(colon) and the key/value pairs are separated by ,}_{Each name is followed by ':'(colon) and the key/value pairs are separated by ,}

(comma). (comma).



 _{The keys must be strings and should be different from each other.}_{The keys must be strings and should be different from each other.} 

 _{Objects should be used when the key names are arbitrary strings.}_{Objects should be used when the key names are arbitrary strings.}

Syntax

{ string : value, ...} { string : value, ...}

Example

Example showing Object: Example showing Object:

{ { "id": "011A", "id": "011A", "language": "JAVA", "language": "JAVA", "price": 500, "price": 500, } }

Whitespace

It can be inserted between any pair of tokens. It can be added to make a code more It can be inserted between any pair of tokens. It can be added to make a code more readable. Example shows declaration with and without whitespace:

readable. Example shows declaration with and without whitespace:

Syntax

{string: {string: " " ",....}",....}

Example

var obj1 =

var obj1 = {"name": "Sachin Tendulkar"}{"name": "Sachin Tendulkar"} var obj2 =

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null

It means empty type. It means empty type.

Syntax

null null

Example

var i = null; var i = null; if(i==1) if(i==1) { { document.write(" document.write("<h1>value is <h1>value is 1</h1>");1</h1>"); } } else else { { document.write("

document.write("<h1>value is <h1>value is null</h1>");null</h1>"); }

}

JSON

JSON V

Value

alue

It includes: It includes:



 _{number (integer or floating point)}_{number (integer or floating point)}   _string_string   _boolean_boolean   _array_array   _object_object   _null_null

Syntax

String | Number | Object | Array | TRUE

Example

var i = 1; var i = 1; var j = "sachin"; var j = "sachin"; var k = null; var k = null;

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Creating Simple Objects

JSON objects can be created with JavaScript. Let us see the various ways of creating JSON objects can be created with JavaScript. Let us see the various ways of creating JSON objects using JavaScript:

JSON objects using JavaScript:



 _{Creation of an empty Object:}_{Creation of an empty Object:}

var JSONObj = {}; var JSONObj = {};



 _{Creation of a new Object:}_{Creation of a new Object:}

var JSONObj = new

var JSONObj = new Object();Object();



 _{Creation of an object with attribute}_{Creation of an object with attribute bookname}_{bookname with value in string,}_{with value in string,}

attribute

attribute priceprice with numeric value. Attribute is accessed by using '.' Operator:with numeric value. Attribute is accessed by using '.' Operator:

var JSONObj = {

var JSONObj = { "bookname ":"VB BLACK BOOK", "price":500 };"bookname ":"VB BLACK BOOK", "price":500 };

This is an example that shows creation of an object in javascript using JSON, save the This is an example that shows creation of an object in javascript using JSON, save the below code as

below code as json_object.htm json_object.htm::

<title>Creating Object JSON with JavaScript</title> <title>Creating Object JSON with JavaScript</title> <script language="javascript" >

var JSONObj

var JSONObj = { "= { "name" : name" : "tutorialspoin"tutorialspoint.com", "year" t.com", "year" : 2005 }: 2005 };; document.write("<

document.write("<h1>JSON with h1>JSON with JavaScript example</h1>");JavaScript example</h1>"); document.write("<br>");

document.write("<h3>Website h3>Website Name="+JSONObj.name+"<Name="+JSONObj.name+"</h3>");/h3>"); document.write("<h3>Year="+JSONObj.year+"</h3>"); document.write("<h3>Year="+JSONObj.year+"</h3>"); </script> </script> </head> </head> <body> <body> </body> </body> </html> </html>

4. JSON

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Now let's try to open json_object.htm json_object.htm using IE or any other javascript enabled browser.using IE or any other javascript enabled browser. It produces the following result:

It produces the following result:

Creating Array Objects

The following example shows creation of an array object in javascript using JSON, save The following example shows creation of an array object in javascript using JSON, save the below code as

the below code as json_array_object json_array_object.htm.htm::

<title>Creation of array object in javascript using JSON</title> <title>Creation of array object in javascript using JSON</title> <script language="javascript" >

document.writeln("<

document.writeln("<h2>JSON array h2>JSON array object</h2>");object</h2>");

var books = { "Pascal" : [ var books = { "Pascal" : [

{ "Name"

{ "Name" : "Pasc: "Pascal Made al Made Simple", "priSimple", "price" : 70ce" : 700 },0 }, { "Name

{ "Name" " : "Gui: "Guide to de to Pascal", "pPascal", "price" : rice" : 400 }400 } ],

],

"Scala" "Scala" : : [[

{ "Name"

{ "Name" : "Scal: "Scala for ta for the Impatient", he Impatient", "price" : "price" : 1000 },1000 }, { "Name

{ "Name" " : "Sca: "Scala in la in Depth", "prDepth", "price" : ice" : 1300 }1300 } ] ] } } var i = 0 var i = 0 document.writeln("<

document.writeln("<table table border='2'><tr>border='2'><tr>");"); for(i=0;i<books.Pascal.length;i++) for(i=0;i<books.Pascal.length;i++) { { document.writeln("<td>"); document.writeln("<td>");

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document.writeln

document.writeln("<table border='1' width=100 ("<table border='1' width=100 >");>"); document.writeln

document.writeln("<tr><td><b>Nam("<tr><td><b>Name</b></td><td e</b></td><td width=50>"width=50>" +

+ books.Pascal[i].Nbooks.Pascal[i].Name+"</td></tr>");ame+"</td></tr>"); document.writeln

document.writeln("<tr><td><b>Pri("<tr><td><b>Price</b></td><td ce</b></td><td width=50>"width=50>" +

+ books.Pascal[i].pbooks.Pascal[i].price rice +"</td></tr>");+"</td></tr>"); document.writeln("</table>"); document.writeln("</table>"); document.writeln("</td>"); document.writeln("</td>"); } } for(i=0;i<books.Scala.length;i++) for(i=0;i<books.Scala.length;i++) { { document.writeln("<td>"); document.writeln("<td>"); document.writeln

document.writeln("<table border='1' width=100 ("<table border='1' width=100 >");>"); document.writeln

document.writeln("<tr><td><b>Nam("<tr><td><b>Name</b></td><td e</b></td><td width=50>"width=50>" +

+ books.Scala[i].Nabooks.Scala[i].Name+"</td></tr>");me+"</td></tr>"); document.writeln

document.writeln("<tr><td><b>Pri("<tr><td><b>Price</b></td><td ce</b></td><td width=50>"width=50>" +

+ books.Scala[i].prbooks.Scala[i].price+"</td></tr>");ice+"</td></tr>"); document.writeln("</table>"); document.writeln("</table>"); document.writeln("</td>"); document.writeln("</td>"); } } document.writeln("</tr></table>"); document.writeln("</tr></table>"); </script> </script> </head> </head> <body> <body> </body> </body> </html> </html>

Now let's try to open json_array_object.htm json_array_object.htm using IE or any other javascript enabledusing IE or any other javascript enabled browser. It produces the following result:

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JSON Schema is a specification for JSON based format for defining the structure of JSON JSON Schema is a specification for JSON based format for defining the structure of JSON data. It was written under IETF draft which expired in 2011. JSON Sch

data. It was written under IETF draft which expired in 2011. JSON Sch ema:ema:



 _{Describes your existing data format.}_{Describes your existing data format.} 

 _{Clear, human- and machine-readable documentation.}_{Clear, human- and machine-readable documentation.} 

 _{Complete structural validation, useful for automated testing.}_{Complete structural validation, useful for automated testing.} 

 _{Complete structural validation, validating client-submitted data.}_{Complete structural validation, validating client-submitted data.}

JSON Schema Validation Libraries

There are several validators currently available for different programming languages. There are several validators currently available for different programming languages. Currently the most complete and compliant JSON Schema validator available is JSV. Currently the most complete and compliant JSON Schema validator available is JSV.

Languages Libraries

C

C WJElement WJElement (LGPLv3)(LGPLv3)

Java

Java json-schema-validator json-schema-validator (LGPLv3)(LGPLv3)

.NET

.NET Json.NET Json.NET (MIT)(MIT)

ActionScript

ActionScript 3 3 Frigga Frigga (MIT)(MIT)

Haskell

Haskell aeson-schema aeson-schema (MIT)(MIT)

Python Jsonschema

Ruby

Ruby autoparse autoparse (ASL (ASL 2.0); 2.0); ruby-jsonschema ruby-jsonschema (MIT)(MIT)

PHP

PHP php-json-schema php-json-schema (MIT). (MIT). json-schema json-schema (Berkeley)(Berkeley)

JavaScript

JavaScript Orderly (BSD); JSV; json-schema; Matic (MIT); Dojo; PersevereOrderly (BSD); JSV; json-schema; Matic (MIT); Dojo; Persevere (modified BSD or AFL 2.0); schema.js.

(modified BSD or AFL 2.0); schema.js.

5. JSON

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JSON Schema Example

Given below is a basic JSON schema, which covers a classical product catalog Given below is a basic JSON schema, which covers a classical product catalog description:

description:

{ {

"$schema":

"$schema": "http://json-sche"http://json-schema.org/draft-04/schema.org/draft-04/schema#",ma#", "title": "Product",

"title": "Product",

"description": "A product from Acme's catalog", "description": "A product from Acme's catalog", "type": "object", "type": "object", "properties": { "properties": { "id": { "id": {

"description": "The unique identifier for a product", "description": "The unique identifier for a product", "type": "integer" "type": "integer" }, }, "name": { "name": {

"description": "Name of the product", "description": "Name of the product", "type": "string" "type": "string" }, }, "price": { "price": { "type": "number", "type": "number", "minimum": 0, "minimum": 0, "exclusiveMini

"exclusiveMinimum": mum": truetrue }

} }, },

"required": ["id", "name", "price"] "required": ["id", "name", "price"] }

}

Let's check the various important keywords that can be used in this schema: Let's check the various important keywords that can be used in this schema:

Keywords Description

$schema

$schema The $schema keyword states that this schema is writtenThe $schema keyword states that this schema is written according to the draft v4 specification.

according to the draft v4 specification.

title

title You You will will use use this this to to give give a a title title to to your your schema.schema.

description

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type

type The type keyword defines the first constraint on our JSON data: itThe type keyword defines the first constraint on our JSON data: it has to be a JSON Object.

has to be a JSON Object.

properties

properties Defines various keys and their value types, minimum andDefines various keys and their value types, minimum and maximum values to be used in JSON file.

maximum values to be used in JSON file.

required

required This This keeps keeps a a list list of of required required properties.properties.

minimum

minimum This is the constraint to be put on the value and representsThis is the constraint to be put on the value and represents minimum acceptable value.

minimum acceptable value.

exclusiveMinimum

exclusiveMinimum If "exclusiveMinimum" is present and has boolean value true, theIf "exclusiveMinimum" is present and has boolean value true, the instance is valid if it is strictly greater than the value of instance is valid if it is strictly greater than the value of "minimum".

"minimum".

maximum

maximum This is the constraint to be put on the value and representsThis is the constraint to be put on the value and represents maximum acceptable value.

maximum acceptable value.

exclusiveMaximum

exclusiveMaximum If "exclusiveMaximum" is present and has boolean value true, theIf "exclusiveMaximum" is present and has boolean value true, the instance is valid if it is strictly lower than the value of instance is valid if it is strictly lower than the value of "maximum".

"maximum".

multipleOf

multipleOf A numeric instance is valid against "multipleOf" if the result of theA numeric instance is valid against "multipleOf" if the result of the division of the instance by this keyword's

division of the instance by this keyword's value is an integer.value is an integer.

maxLength

maxLength The length of a string instance is defined as the maximumThe length of a string instance is defined as the maximum number of its characters.

number of its characters.

minLength

minLength The length of a string instance is defined as the minimum numberThe length of a string instance is defined as the minimum number of its characters.

of its characters.

pattern

pattern A string instance is considered valid if the regular expressionA string instance is considered valid if the regular expression matches the instance successfully.

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You can check a

You can check a http://json-schema.orghttp://json-schema.org for the complete list of keywords that can befor the complete list of keywords that can be used in defining a JSON schema. The above schema can be used to test the validity of used in defining a JSON schema. The above schema can be used to test the validity of the following JSON code:

the following JSON code:

[ [ { { "id": 2, "id": 2,

"name": "An ice sculpture", "name": "An ice sculpture", "price": 12.50, "price": 12.50, }, }, { { "id": 3, "id": 3,

"name": "A blue mouse", "name": "A blue mouse", "price": 25.50, "price": 25.50, } } ] ]

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JSON and XML are human readable formats and are language independent. They both JSON and XML are human readable formats and are language independent. They both have support for creation, reading and decoding in real world situations. We can have support for creation, reading and decoding in real world situations. We can compare JSON with XML, based on the following factors:

compare JSON with XML, based on the following factors:

Verbose

XML is more verbose than JSON, so it is faster to write JSON for programmers. XML is more verbose than JSON, so it is faster to write JSON for programmers.

Arrays Usage

XML is used to describe the structured data, which doesn't include arrays whereas JSON XML is used to describe the structured data, which doesn't include arrays whereas JSON include arrays.

include arrays.

Parsing

JavaScript's

JavaScript's eval eval method parses JSON. When applied to JSON, eval returns the describedmethod parses JSON. When applied to JSON, eval returns the described object.

object.

Example

Individual examples of XML and JSON: Individual examples of XML and JSON:

JSON

{ { "company": Volkswagen, "company": Volkswagen, "name": "Vento", "name": "Vento", "price": 800000 "price": 800000 } }

XML

<car> <car> <company>Volkswagen</company> <company>Volkswagen</company> <name>Vento</name> <name>Vento</name> <price>800000</price> <price>800000</price> </car> </car>

6. JSON

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This chapter covers how to encode and decode JSON objects using PHP programming This chapter covers how to encode and decode JSON objects using PHP programming language. Let's start with preparing the environment to start our programming with PHP language. Let's start with preparing the environment to start our programming with PHP for JSON.

for JSON.

Environment

As of PHP 5.2.0, the JSON extension is bundled and compiled into PHP by default. As of PHP 5.2.0, the JSON extension is bundled and compiled into PHP by default.

JSON Functions

Function Libraries

json_encode

json_encode Returns the JSON representation of a value.Returns the JSON representation of a value.

json_decode

json_decode Decodes a JSON string.Decodes a JSON string.

json_last_error

json_last_error Returns the last error occurred.Returns the last error occurred.

Encoding JSON in PHP (json_encode)

PHP json_encode() function is used for encoding JSON in PHP. This function returns the PHP json_encode() function is used for encoding JSON in PHP. This function returns the JSON representation of a value on success o

JSON representation of a value on success o r FALSE on failure.r FALSE on failure.

Syntax

string json_encode ( $value [, $options = 0 ] ) string json_encode ( $value [, $options = 0 ] )

Parameters



 _value_{value: The value being encoded. This function only works with UTF-8 encoded}_{: The value being encoded. This function only works with UTF-8 encoded}

data. data.



 _options_{options: This optional value is a bitmask consisting of JSON_HEX_QUOT,}_{: This optional value is a bitmask consisting of JSON_HEX_QUOT,}

JSON_HEX_TAG, JSON_HEX_AMP, JSON_HEX_APOS, JSON_HEX_TAG, JSON_HEX_AMP, JSON_HEX_APOS,

JSON_NUMERIC_CHECK,JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, JSON_NUMERIC_CHECK,JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, JSON_FORCE_OBJECT.

JSON_FORCE_OBJECT.

7. JSON

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Example

The following example shows how to convert an array into JSON with PHP: The following example shows how to convert an array into JSON with PHP:

<?php <?php

$arr = array('a' => 1, 'b' => 2, 'c'

$arr = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => => 3, 'd' => 4, 'e' => 5);5); echo

echo json_encode($arr);json_encode($arr); ?>

?>

While executing, this will produce the following result: While executing, this will produce the following result:

{"a":1,"b":2,"c":3,"d":4,"e":5} {"a":1,"b":2,"c":3,"d":4,"e":5}

The following example shows how the PHP objects can be converted into JSON: The following example shows how the PHP objects can be converted into JSON:

<?php <?php class Emp { class Emp { public $name = ""; public $name = ""; public

public $hobbies $hobbies = = "";""; public $birthdate = ""; public $birthdate = ""; } } $e = new Emp(); $e = new Emp(); $e->name = "sachin"; $e->name = "sachin"; $e->hobbies

$e->hobbies = = "sports";"sports";

$e->birthdate = date('m/d/Y h:i:s a', "8/5/1974 12:20:03 p"); $e->birthdate = date('m/d/Y h:i:s a', "8/5/1974 12:20:03 p"); $e->birthdate = date('m/d/Y h:i:s a',

$e->birthdate = date('m/d/Y h:i:s a', strtotime("8/5/197strtotime("8/5/1974 12:20:03"));4 12:20:03"));

echo json_encode($e); echo json_encode($e); ?>

?>

{"name":"sachin","h

{"name":"sachin","hobbies":"sports","biobbies":"sports","birthdate":"08\/05\/rthdate":"08\/05\/1974 1974 12:20:03 12:20:03 pm"}pm"}

Decoding JSON in PHP (json_decode)

PHP json_decode() function is used for decoding JSON in PHP. This function returns the PHP json_decode() function is used for decoding JSON in PHP. This function returns the value decoded from json to appropriate PHP type.

value decoded from json to appropriate PHP type.

Syntax

mixed json_decode ($json [,$assoc = false [, $depth = 512 [, $options = 0 ]]]) mixed json_decode ($json [,$assoc = false [, $depth = 512 [, $options = 0 ]]])

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Paramaters



 _{json_string}_{json_string: It is an encoded string which must be UTF-8 encoded data.}_{: It is an encoded string which must be UTF-8 encoded data.} 

 _assoc_{assoc: It is a boolean type parameter, when set}_{: It is a boolean type parameter, when set to TRUE, returned objects will be}_{to TRUE, returned objects will be}

converted into associative arrays. converted into associative arrays.



 _depth_{depth: It is an integer type parameter which specifies recursion depth}_{: It is an integer type parameter which specifies recursion depth} 

 _options:_options_: _It_It _is_is _an_an _integer_integer _type_type _bitmask_bitmask _of_of _JSON_JSON _decode,_decode,

JSON_BIGINT_AS_STRING is supported. JSON_BIGINT_AS_STRING is supported.

Example

The following example shows how PHP can be used to decode JSON objects: The following example shows how PHP can be used to decode JSON objects:

<?php <?php

$json =

$json = '{"a":1,"b":2,'{"a":1,"b":2,"c":3,"d":4,"e":5}';"c":3,"d":4,"e":5}';

var_dump(json_decode($json)); var_dump(json_decode($json)); var_dump(json_de

var_dump(json_decode($json, code($json, true));true)); ?>

?>

While executing, it will produce the following result: While executing, it will produce the following result:

object(stdClass)#1 (5) { object(stdClass)#1 (5) { ["a"] => int(1) ["a"] => int(1) ["b"] => int(2) ["b"] => int(2) ["c"] => int(3) ["c"] => int(3) ["d"] => int(4) ["d"] => int(4) ["e"] => int(5) ["e"] => int(5) } } array(5) { array(5) { ["a"] => int(1) ["a"] => int(1) ["b"] => int(2) ["b"] => int(2) ["c"] => int(3) ["c"] => int(3) ["d"] => int(4) ["d"] => int(4) ["e"] => int(5) ["e"] => int(5) } }

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This

This chapter covers chapter covers how to how to encode and encode and decode JSON decode JSON objects using Pobjects using Perl programmingerl programming language. Let's start with preparing the environment to start our programming with Perl language. Let's start with preparing the environment to start our programming with Perl for JSON.

for JSON.

Environment

Before you start encoding and decoding JSON using Perl, you need to install JSON Before you start encoding and decoding JSON using Perl, you need to install JSON module, which can be obtained from CPAN. Once you downloaded JSON-2.53.tar.gz or module, which can be obtained from CPAN. Once you downloaded JSON-2.53.tar.gz or any other latest version, follow the steps mentioned b

any other latest version, follow the steps mentioned below:elow:

$tar xvfz

$tar xvfz JSON-2.53.tar.gzJSON-2.53.tar.gz $cd JSON-2.53 $cd JSON-2.53 $perl Makefile.PL $perl Makefile.PL $make $make $make install $make install

JSON Functions

Function Libraries Function Libraries encode_json

encode_json Converts the given Perl data structure to a UTF-8 encoded, binaryConverts the given Perl data structure to a UTF-8 encoded, binary string.

string.

decode_json

decode_json Decodes Decodes a a JSON JSON string.string.

to_json

to_json Converts Converts the the given given Perl Perl data data structure structure to to a a json json string.string.

from_json

from_json Expects a json string and tries to parse it, returning the resultingExpects a json string and tries to parse it, returning the resulting reference.

reference.

convert_blessed

convert_blessed Use this function with true value so that Perl can use TO_JSONUse this function with true value so that Perl can use TO_JSON method on the object's class to convert an object into JSON.

method on the object's class to convert an object into JSON.

8. JSON

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Encoding JSON in Perl (encode_json)

Perl encode_json() function converts the given Perl data structure to a UTF-8 encoded, Perl encode_json() function converts the given Perl data structure to a UTF-8 encoded, binary string.

binary string.

Syntax:

$json_text = encode_json ($perl_scalar ); $json_text = encode_json ($perl_scalar );

or or

$json_text =

$json_text = JSON->new->utf8->encJSON->new->utf8->encode($perl_scalar);ode($perl_scalar);

Example

The following example shows arrays under JSON with Perl: The following example shows arrays under JSON with Perl:

#!/usr/bin/perl

use JSON; use JSON;

my %rec_hash = ('a' => 1, 'b' =>

my %rec_hash = ('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 2, 'c' => 3, 'd' => 4, 'e' => 5);'e' => 5); my $json =

my $json = encode_json \%rec_hash;encode_json \%rec_hash; print "$json\n";

print "$json\n";

{"e":5,"c":3,"a":1,"b":2,"d":4} {"e":5,"c":3,"a":1,"b":2,"d":4}

The following example shows how Perl objects can be converted into JSON: The following example shows how Perl objects can be converted into JSON:

#!/usr/bin/perl

package Emp; package Emp; sub new sub new { { my $class = shift; my $class = shift; my $self = { my $self = { name => shift, name => shift, hobbies

hobbies => => shift,shift, birthdate

birthdate => => shift,shift, };

};

bless $self, $class; bless $self, $class;

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return $self; return $self; }

}

sub TO_JSON { return { %{ shift() } }; sub TO_JSON { return { %{ shift() } }; }}

package main; package main; use JSON; use JSON;

my

my $JSON $JSON = = JSON->new->utf8;JSON->new->utf8; $JSON->convert_blessed(1); $JSON->convert_blessed(1);

$e = new

$e = new Emp( "sachin", "sports", "8/5/1974 12:20:03 pm");Emp( "sachin", "sports", "8/5/1974 12:20:03 pm"); $json =

$json = $JSON->encode($e);$JSON->encode($e); print "$json\n";

print "$json\n";

On executing, it will produce the following result: On executing, it will produce the following result:

{"birthdate":"8/5/1

{"birthdate":"8/5/1974 974 12:20:03 12:20:03 pm","name":"sachin","hopm","name":"sachin","hobbies":"sports"}bbies":"sports"}

Decoding JSON in Perl (decode_json)

Perl decode_json() function is used for decoding JSON in Perl. This function returns the Perl decode_json() function is used for decoding JSON in Perl. This function returns the value decoded from json to an appropriate Perl type.

value decoded from json to an appropriate Perl type.

Syntax:

$perl_scalar = decode_json $json_text $perl_scalar = decode_json $json_text

or or

$perl_scalar =

$perl_scalar = JSON->new->utf8->dJSON->new->utf8->decode($json_text)ecode($json_text)

Example

The following example shows how Perl can be used to decode JSON objects. Here you The following example shows how Perl can be used to decode JSON objects. Here you will need to install Data::Dumper module if you already do not have it on your machine. will need to install Data::Dumper module if you already do not have it on your machine.

#!/usr/bin/perl

use JSON; use JSON; use Data::Dumper; use Data::Dumper; $json

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$text =

$text = decode_json($json);decode_json($json); print Dumper($text);

print Dumper($text);

On executing, it will produce following result: On executing, it will produce following result:

$VAR1 = { $VAR1 = { 'e' => 5, 'e' => 5, 'c' => 3, 'c' => 3, 'a' => 1, 'a' => 1, 'b' => 2, 'b' => 2, 'd' => 4 'd' => 4 }; };

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This chapter covers how to encode and decode JSON objects using Python programming This chapter covers how to encode and decode JSON objects using Python programming language. Let's start with preparing the environment to start our programming with language. Let's start with preparing the environment to start our programming with Python for JSON.

Python for JSON.

Environment

Before you start with encoding and decoding JSON using Python, you need to install any Before you start with encoding and decoding JSON using Python, you need to install any of the JSON modules available. For this tutorial we have downloaded and installed of the JSON modules available. For this tutorial we have downloaded and installed Demjson (http://deron.meranda.us/python/demjson/)

Demjson (http://deron.meranda.us/python/demjson/) as follows:as follows:

$tar xvfz

$tar xvfz demjson-1.6.tar.gdemjson-1.6.tar.gzz $cd demjson-1.6

$cd demjson-1.6

$python setup.py install $python setup.py install

JSON Functions

Function Libraries

encode

encode Encodes Encodes the the Python Python object object into into a a JSON JSON string string representation.representation.

decode

decode Decodes Decodes a a JSON-endoded JSON-endoded string string into into a a Python Python object.object.

Encoding JSON in P

Encoding JSON in Python (encode)

ython (encode)

Python encode() function encodes the Python object into a JSON string representation. Python encode() function encodes the Python object into a JSON string representation.

Syntax

demjson.encode(self

demjson.encode(self, , obj, nest_level=0)obj, nest_level=0)

Example

The following example shows arrays under JSON with Python. The following example shows arrays under JSON with Python.

#!/usr/bin/python

import demjson import demjson

data = [ { 'a' : 1, 'b' : 2, 'c' : 3, 'd' : 4, 'e' : 5 } ] data = [ { 'a' : 1, 'b' : 2, 'c' : 3, 'd' : 4, 'e' : 5 } ]

9. JSON

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json =

json = demjson.encode(demjson.encode(data)data) print json

print json

[{"a":1,"b":2,"c":3,"d":4,"e":5}] [{"a":1,"b":2,"c":3,"d":4,"e":5}]

Decoding JSON in Python (decode)

Python can use demjson.decode() function for decoding JSON. This function returns the Python can use demjson.decode() function for decoding JSON. This function returns the value decoded from json to an appropriate Python type.

value decoded from json to an appropriate Python type.

Syntax

demjson.decode(self demjson.decode(self, , txt)txt)

Example

The following example shows how Python can be used to decode JSON objects. The following example shows how Python can be used to decode JSON objects.

#!/usr/bin/python

import demjson import demjson

json

json = = '{"a":1,"b":'{"a":1,"b":2,"c":3,"d":4,"e2,"c":3,"d":4,"e":5}';":5}';

text =

text = demjson.decode(demjson.decode(json)json) print text

print text

{u'a': 1, u'c': 3, u'b': 2, u'e': 5, u'd': 4} {u'a': 1, u'c': 3, u'b': 2, u'e': 5, u'd': 4}

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This

This chapter covers how chapter covers how to encode to encode and decode JSON and decode JSON objects using Ruby objects using Ruby programmingprogramming language. Let's start with preparing the environment to start our programming with language. Let's start with preparing the environment to start our programming with Ruby for JSON.

Ruby for JSON.

Environment

Before you start with encoding and decoding JSON using Ruby, you need to install any of Before you start with encoding and decoding JSON using Ruby, you need to install any of the JSON modules available for Ruby. You may need to install Ruby gem, but if you are the JSON modules available for Ruby. You may need to install Ruby gem, but if you are running latest version of Ruby then you must have gem already installed on your running latest version of Ruby then you must have gem already installed on your machine, otherwise let's follow the following single step assuming you already have gem machine, otherwise let's follow the following single step assuming you already have gem installed:

installed:

$gem install json $gem install json

Parsing JSON using Ruby

The following example shows that the first 2 keys hold string values and the last 3 keys The following example shows that the first 2 keys hold string values and the last 3 keys hold arrays of strings. Let's keep the following content in a file called

hold arrays of strings. Let's keep the following content in a file called input.jsoninput.json..

{ {

"President": "Alan Isaac", "President": "Alan Isaac", "CEO": "David Richardson", "CEO": "David Richardson",

"India": [ "India": [ "Sachin Tendulkar", "Sachin Tendulkar", "Virender Sehwag", "Virender Sehwag", "Gautam Gambhir", "Gautam Gambhir", ], ], "Srilanka": [ "Srilanka": [ "Lasith Malinga", "Lasith Malinga", "Angelo Mathews", "Angelo Mathews", "Kumar Sangakkara" "Kumar Sangakkara" ], ], "England": [ "England": [ "Alastair Cook", "Alastair Cook",

10. JSON

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"Jonathan Trott", "Jonathan Trott", "Kevin Pietersen" "Kevin Pietersen" ] ] } }

Given below is a Ruby program that will be used to parse the above mentioned JSON Given below is a Ruby program that will be used to parse the above mentioned JSON document: document:

#!/usr/bin/ruby

require 'rubygems' require 'rubygems' require 'json' require 'json' require 'pp' require 'pp' json =

json = File.read('inpuFile.read('input.json')t.json') obj =

obj = JSON.parse(json)JSON.parse(json)

pp obj pp obj

{"President"=>"Alan Isaac", {"President"=>"Alan Isaac", "CEO"=>"David Richardson", "CEO"=>"David Richardson", "India"=> "India"=>

["Sachin Tendulkar", "Virender Sehwag", "Gautam Gambhir"], ["Sachin Tendulkar", "Virender Sehwag", "Gautam Gambhir"],

"Srilanka"=> "Srilanka"=>

["Lasith Malinga ", "Angelo

["Lasith Malinga ", "Angelo Mathews", "Kumar Sangakkara"],Mathews", "Kumar Sangakkara"],

"England"=> "England"=>

["Alastair Cook", "Jonathan Trott", "Kevin Pietersen"] ["Alastair Cook", "Jonathan Trott", "Kevin Pietersen"] }

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This

This chapter covers how chapter covers how to encode and to encode and decode JSON objects decode JSON objects using Java programmusing Java programminging language. Let's start with preparing the environment to start our programming with Java language. Let's start with preparing the environment to start our programming with Java for JSON.

for JSON.

Environment

Before you start with encoding and decoding JSON using Java, you need to install any of Before you start with encoding and decoding JSON using Java, you need to install any of the JSON modules available. For this tutorial we have downloaded and the JSON modules available. For this tutorial we have downloaded and installed

installed JSON.simple (https://code.google.com/p/json-simple/)JSON.simple (https://code.google.com/p/json-simple/) and have added theand have added the location of

location of json-simple-1.1.1.jar json-simple-1.1.1.jar file to the environment variable CLASSPATH.file to the environment variable CLASSPATH.

Mapping between JSON and Java entities

JSON.simple maps entities from the left side to the right side while decoding or parsing, JSON.simple maps entities from the left side to the right side while decoding or parsing, and maps entities from the right to the left while encoding.

and maps entities from the right to the left while encoding.

JSON Java JSON Java string java.lang.String string java.lang.String number java.lang.Number number java.lang.Number true|false ava.lang.Boolean true|false ava.lang.Boolean null null null null array java.util.List array java.util.List object java.util.Map object java.util.Map

On decoding, the default concrete class of

On decoding, the default concrete class of java.util.List java.util.List isis org.json.simple.JSONArray org.json.simple.JSONArray andand the default concrete class of

the default concrete class of java.util.Map java.util.Map isis org.json.simple.JSONObject org.json.simple.JSONObject ..

11. JSON

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Encoding JSON in Java

Following is a simple example to encode a JSON object using Java JSONObject which is a Following is a simple example to encode a JSON object using Java JSONObject which is a subclass of java.util.HashMap. No ordering is provided. If you need the strict ordering of subclass of java.util.HashMap. No ordering is provided. If you need the strict ordering of elements, use JSONValue.toJSONString (map) method with

elements, use JSONValue.toJSONString (map) method with ordered map implementationordered map implementation such as java.util.LinkedHashMap.

such as java.util.LinkedHashMap.

import

import org.json.simpleorg.json.simple.JSONObject;.JSONObject;

class JsonEncodeDemo class JsonEncodeDemo {

{

public static void main(String[] args) public static void main(String[] args) {

{

JSONObject obj = new JSONObject(); JSONObject obj = new JSONObject();

obj.put("name", "foo"); obj.put("name", "foo"); obj.put("num", new

obj.put("num", new Integer(100));Integer(100)); obj.put("balanc

obj.put("balance", e", new new Double(1000.21)Double(1000.21));); obj.put("is_vip"

obj.put("is_vip", , new new Boolean(true));Boolean(true));

System.out.print(obj); System.out.print(obj); } } } }

On compiling and executing the above program

On compiling and executing the above program the following result will be generated:the following result will be generated:

{"balance": 1000.21, "num":100,

{"balance": 1000.21, "num":100, "is_vip":true, "name":"foo"}"is_vip":true, "name":"foo"}

Following is another example that shows a JSON object streaming using Java Following is another example that shows a JSON object streaming using Java JSONObject:

JSONObject:

import

import org.json.simpleorg.json.simple.JSONObject;.JSONObject;

class JsonEncodeDemo class JsonEncodeDemo {

{

JSONObject obj = new JSONObject(); JSONObject obj = new JSONObject();

obj.put("name","foo"); obj.put("name","foo"); obj.put("num",ne

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obj.put("balanc

obj.put("balance",new e",new Double(1000.21))Double(1000.21));; obj.put("is_vip

obj.put("is_vip",new ",new Boolean(true));Boolean(true));

StringWriter out =

StringWriter out = new StringWriter();new StringWriter(); obj.writeJSONString(out);

obj.writeJSONString(out);

String jsonText =

String jsonText = out.toString();out.toString(); System.out.print(jsonText); System.out.print(jsonText); } } } }

On compiling and executing the above program

On compiling and executing the above program the following result is generated:the following result is generated:

{"balance": 1000.21, "num":100,

{"balance": 1000.21, "num":100, "is_vip":true, "name":"foo"}"is_vip":true, "name":"foo"}

Decoding JSON in Java

The following example makes use of

The following example makes use of JSONObjectJSONObject andand JSONArrayJSONArray where JSONObject iswhere JSONObject is a java.util.Map and JSONArray is a java.util.List, so you can access them with standard a java.util.Map and JSONArray is a java.util.List, so you can access them with standard operations of Map or List.

operations of Map or List.

import

import org.json.simpleorg.json.simple.JSONObject;.JSONObject; import

import org.json.simpleorg.json.simple.JSONArray;.JSONArray; import

import org.json.simpleorg.json.simple.parser.ParseExcept.parser.ParseException;ion; import

import org.json.simpleorg.json.simple.parser.JSONParser;.parser.JSONParser;

class JsonDecodeDemo class JsonDecodeDemo {

{

JSONParser parser=new JSONParser(); JSONParser parser=new JSONParser(); String s

String s = = "[0,{\"1\":{\"2\""[0,{\"1\":{\"2\":{\"3\":{\"4\":[5,:{\"3\":{\"4\":[5,{\"6\":7}]}}}}]";{\"6\":7}]}}}}]"; try{

try{

Object obj =

Object obj = parser.parse(s);parser.parse(s); JSONArray array =

JSONArray array = (JSONArray)obj;(JSONArray)obj; System.out.print

System.out.println("The 2nd element of ln("The 2nd element of array");array"); System.out.println(array.get(1));

System.out.println(array.get(1)); System.out.println();

System.out.println();

JSONObject obj2 =

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System.out.print System.out.println("Field ln("Field \"1\"");\"1\""); System.out.println(obj2.get("1")); System.out.println(obj2.get("1")); s = "{}"; s = "{}"; obj =

obj = parser.parse(s);parser.parse(s); System.out.println(obj); System.out.println(obj);

s= "[5,]"; s= "[5,]"; obj =

obj = parser.parse(s);parser.parse(s); System.out.println(obj); System.out.println(obj);

s= "[5,,2]"; s= "[5,,2]"; obj =

obj = parser.parse(s);parser.parse(s); System.out.println(obj); System.out.println(obj); }catch(ParseExc

}catch(ParseException eption pe){pe){ System.out.print

System.out.println("position: " ln("position: " + + pe.getPosition());pe.getPosition()); System.out.println(pe); System.out.println(pe); } } } } } }

On compiling and executing the above program, the following result will be generated: On compiling and executing the above program, the following result will be generated:

The 2nd element of array The 2nd element of array

{"1":{"2":{"3":{"4":[5,{"6":7}]}}}} {"1":{"2":{"3":{"4":[5,{"6":7}]}}}} Field "1" Field "1" {"2":{"3":{"4":[5,{"6":7}]}}} {"2":{"3":{"4":[5,{"6":7}]}}} {} {} [5] [5] [5,2] [5,2]