What is JSON. What is use of JSON. Working with JSON in Salesforce

1. Salesforce JSON support
Winter 12
By – Jitendra Zaa
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2. Agenda
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•
•
•
•
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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
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3. What is JSON
•
•
•
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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.
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4. XML Example
<Person>
<FirstName>Foo</FirstName>
<LastName>Bar</LastName>
</person>
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5. JSON Example
{
“FirstName” : “Foo”,
“LastName” : “Bar”
}
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6. JSON Advantage over XML
• XML is Verbose.
• More size than of equivalent JSON representation
because of repeated Tags.
• JSON Simple to represent
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7. 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.
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8. 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. Boolean
2. Number
3. String
4. Object
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9. Nested Object JSON
{
“FirstName” : “Foo”,
“LastName” : “Bar”,
“Address” :
{
“city” : “Pune”,
“state” : “Maharashtra”,
“country” : “India”
}
}
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10. How to Work with JSON – Before
Winter 12
• AppExchange and other codes were available for
Parsing JSON.
• Performance Overhead.
• Learning curve more.
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11. Deserialize JSON – Winter 12 API
JSON String :
{
“FirstName” : “Foo”,
“LastName” : “Bar”
}
Equivalent Apex Class:
Class Person
{
public String FirstName;
public String LastName;
}
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12. Deserialize JSON – Single Line
Person d = (Person )System.JSON.deserialize(jsonString, Person.class);
JSON Format String
Determine the output
object type of the JSON
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13. Serialize Apex Class to JSON
JSON.serialize(object);
Object to convert to
JSON
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14. JSON MIME Type
• application/json
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15. Visualforce Page Output as JSON
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contentType="application/x-JavaScript; charset=utf-8"
showHeader="false"
standardStylesheets="false"
sidebar="false"
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16. Demo
Get distance between two points using Google API
http://maps.googleapis.com/maps/api/distancematrix/json?origi
ns=Nagpur+Maharashtra+india&destinations=Pune+Maharasht
ra+india&sensor=false
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17. 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"
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18. Apex Class Equivalent to JSON
response
Class GoogleResponse
{
public String[] destination_addresses;
public String[] origin_addresses;
public Row[] rows;
public String status;
}
Class Row
{
public Elements[] elements;
}
Class Elements
{
public
public
public
}
Class Values
{
public
public
}
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Values distance;
Values duration;
String status;
String text;
String value;

19. 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);
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