JSON Support in Salesforce - winter 12

By – Jitendra Zaa

Salesforce JSON supportWinter 12

1

Agenda

• What is JSON• Advantage of JSON over XML• Other reasons to use JSON• JSON Syntax / Guidelines• Deserialize and Serialize in Single line - Winter 12• Visualforce Page Output as JSON • Google Map API - Demo

2

What is JSON

• JSON Stands for “JavaScript Object Notation”.• Language Independent representation of objects.• Parsers widely available in many languages.• Alternative to XML.• JSON can be transmitted over http / https.

3

XML Example

<Person><FirstName>Foo</FirstName><LastName>Bar</LastName></person>

4

JSON Example

{“FirstName” : “Foo”,“LastName” : “Bar”

}

5

JSON Advantage over XML

• XML is Verbose.• More size than of equivalent JSON representation

because of repeated Tags.• JSON Simple to represent

6

Why JSON

• REST is very common and supports JSON widely.• REST and JSON are the music of the internet.• Google , Yahoo, D&B web services exposed as REST

with response type JSON.

7

JSON Guidelines

Key – Value enclosed in double quotes (String).Value - can again anything of datatype.{} – represents Object[] – represents Array, - Separates data element within Object

Supports basically four data type:1. Boolean2. Number3. String 4. Object

8

Nested Object JSON

{“FirstName” : “Foo”,“LastName” : “Bar”,“Address” :{

“city” : “Pune”,“state” : “Maharashtra”,“country” : “India”

}}

9

How to Work with JSON – Before Winter 12

• AppExchange and other codes were available for Parsing JSON.

• Performance Overhead.• Learning curve more.

10

Deserialize JSON – Winter 12 API

JSON String :{

“FirstName” : “Foo”,“LastName” : “Bar”

}

Equivalent Apex Class:Class Person{

public String FirstName;public String LastName;

}

11

Deserialize JSON – Single Line

Person d = (Person )System.JSON.deserialize(jsonString, Person.class);

12

JSON Format String

Determine the output object type of the JSON

Serialize Apex Class to JSON

JSON.serialize(object);

13

Object to convert to JSON

JSON MIME Type

• application/json

14

Visualforce Page Output as JSON

• contentType="application/x-JavaScript; charset=utf-8"

• showHeader="false" • standardStylesheets="false" • sidebar="false"

15

Demo

Get distance between two points using Google API

http://maps.googleapis.com/maps/api/distancematrix/json?origins=Nagpur+Maharashtra+india&destinations=Pune+Maharashtra+india&sensor=false

16

Response from Google

{   destination_addresses:[      "Pune, Maharashtra, India"   ],   origin_addresses:[      "Nagpur, Maharashtra, India"   ],   rows:[      {         elements:[            {               distance:{                  text:"730 km",                  value:730315               },               duration:{                  text:"11 hours 25 mins",                  value:41126               },               status:"OK"            }         ]      }   ],   status:"OK"}

17

Apex Class Equivalent to JSON responseClass GoogleResponse

{public String[] destination_addresses; public String[] origin_addresses;public Row[] rows;public String status;

}Class Row{

public Elements[] elements;

}Class Elements{

public Values distance;public Values duration;public String status;

}Class Values{

public String text;public String value;

}18

Deserialize JSON

String json = '{ "destination_addresses":[ "Pune, Maharashtra, India" ], "origin_addresses":[ "Nagpur, Maharashtra, India" ],"rows":[ { "elements":[ { "distance":{ "text":"730 km", "value":730315 }, "duration":{ "text":"11 hours 25 mins", "value":41126 }, "status":"OK" } ] } ], "status":"OK"}';

GoogleResponse d = (GoogleResponse)System.JSON.deserialize(json, GoogleResponse.class);

19