Demystifying Salesforce REST API Part 2: Parsing JSON in Salesforce

October 14, 2015
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let us have a look at sampleJSON response from the HTTP request we have created in Salesforce Rest API Integration Part 1.

  
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{
 "results": [{ 
  "gender": "male",
  "name": { 
   "title": "mr",
   "first": "luis",
   "last": "mora"
  },
  "location": { 
   "street": "5004 calle de arturo soria",
   "city": "talavera de la reina",
   "state": "región de murcia",
   "postcode": 47623
  },
  "email": "luis.mora@example.com",
  "login": {
   "username": "greenbird173",
   "password": "bones",
   "salt": "Z0InytVP",
   "md5": "4133a147e63fd1cacaa11c107157bbd9",
   "sha1": "59a07b0a9f5209153e15e7cd6f9ed44e5853b547",
   "sha256": "d85f0d7241c09bc1044b923b55f2eaa8f7b4805208dd001294b23e83d6af51de"
  },
  "registered": 1218507830,
  "dob": 1196943294,
  "phone": "952-069-556",
  "cell": "655-704-166",
  "id": {
   "name": "DNI",
   "value": "03541125-Y"
  },
  "picture": {
   "large": "https://randomuser.me/api/portraits/men/6.jpg",
   "medium": "https://randomuser.me/api/portraits/med/men/6.jpg",
   "thumbnail": "https://randomuser.me/api/portraits/thumb/men/6.jpg"
  },
  "nat": "ES"
 }], 
 "info": { 
  "seed": "500c13f32b0e719c",
  "results": 1,
  "page": 1,
  "version": "1.0"
 }
}


Step 1: Understanding JSON 

In JSON each curly braces enclosure represents a object which is represented in Apex by a inner or wrapper class. Each Square braces represents an array which is a list or array in Apex. For parsing JSON in Apex we have to recreate entire structure in Apex using inner class. 

 Step 2: Creating a JSON wrapper 

Complete JSON Apex Wrapper for the above JSON data structure will look like. 


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public class data{

 public list results {get;set;}
 public info info{get;set;}
}

//result object wrapper
public class result{

public string gender{get;set;}
public Name name{get;set;} //Name Object
public Location location {get;set;} //Location Object    
Public string email{get;set;}   
public Login login {get;set;}
Public Integer registered{get;set;}
Public Integer dob{get;set;}
Public string phone{get;set;}
Public string cell{get;set;}
Public Id1 ido{get;set;}
Public picture picture{get;set;}
Public string nat{get;set;}
}

//Name Object Wrapper
public class Name{

Public string title{get;set;}
Public string first{get;set;}
Public string last{get;set;}

}   

//Location Object Wrapper
public class Location{

Public string street{get;set;}
Public string city{get;set;}
Public string state{get;set;}
Public string postcode{get;set;}
    
}    
    
public class Picture{

Public string large{get;set;}
Public string medium{get;set;}
Public string thumbnail{get;set;}
}

public class Id1{

Public string name{get;set;}
Public string value{get;set;}
}


public class Login{

Public string username{get;set;}
Public string password{get;set;}
Public string salt{get;set;}
Public string md5{get;set;}
Public string sha1{get;set;}
Public string sha256{get;set;}
}

public class info{

Public string seed{get;set;}
Public Integer results{get;set;}
Public string page{get;set;}
Public string version{get;set;}
}

Step 3: Parsing JSON 

Salesforce provides JSONParser class,by using the same we will parse the JSON as below.

  
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//Parse Json from response
  JSONParser parser = JSON.createParser(JSONresponse);
            while (parser.nextToken() != null) {
                   
                    if (parser.getCurrentToken() == JSONToken.START_OBJECT) {
                        // Read entire JSON object, including its array of items.
                     
                      UserData = (data)parser.readValueAs(data.class);  
                       system.debug( UserData);  
                 }
                }

Let us see how our complete class looks like:
  
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Public class FetchUserData{
    
public Data UserData{get;set;}
public String JSONresponse{get;set;}
            
    Public pageReference RefreshUserData(){
        
        //Create Request
  Http httpProtocol = new Http();
        HttpRequest request = new HttpRequest();
        
        //End point will be your rest service URL
        String endpoint = 'https://randomuser.me/api/';
        request.setEndPoint(endpoint);
        request.setMethod('GET');
  
  //Get response
  HttpResponse response = httpProtocol.send(request);
        JSONresponse = response.getBody();
        system.debug(JSONresponse);
  
  
  //Parse Json from response
  JSONParser parser = JSON.createParser(JSONresponse);
            while (parser.nextToken() != null) {
                   
                    if (parser.getCurrentToken() == JSONToken.START_OBJECT) {
                        // Read entire JSON object, including its array of items.
                     
                      UserData = (data)parser.readValueAs(data.class);  
                       system.debug( UserData);  
                 }
                }
        return null;
    }
    
//Wrapper classes for creating JSON structure start here    
public class data{

 public list results {get;set;}
 public info info{get;set;}
}

//result object wrapper
public class result{

public string gender{get;set;}
public Name name{get;set;} //Name Object
public Location location {get;set;} //Location Object    
Public string email{get;set;}   
public Login login {get;set;}
Public Integer registered{get;set;}
Public Integer dob{get;set;}
Public string phone{get;set;}
Public string cell{get;set;}
Public Id1 ido{get;set;}
Public picture picture{get;set;}
Public string nat{get;set;}
}

//Name Object Wrapper
public class Name{

Public string title{get;set;}
Public string first{get;set;}
Public string last{get;set;}

}   

//Location Object Wrapper
public class Location{

Public string street{get;set;}
Public string city{get;set;}
Public string state{get;set;}
Public string postcode{get;set;}
    
}    
    
public class Picture{

Public string large{get;set;}
Public string medium{get;set;}
Public string thumbnail{get;set;}
}

public class Id1{

Public string name{get;set;}
Public string value{get;set;}
}


public class Login{

Public string username{get;set;}
Public string password{get;set;}
Public string salt{get;set;}
Public string md5{get;set;}
Public string sha1{get;set;}
Public string sha256{get;set;}
}

public class info{

Public string seed{get;set;}
Public Integer results{get;set;}
Public string page{get;set;}
Public string version{get;set;}
}
//End of Wrapper Classes
}


Step 4: Displaying rendered JSON in Visualforce


 Let us see how to get the data from Wrapper classes and Display the same in VisulForce Page. Here we a refresh button where user can refresh the data on screen
  
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<apex:page controller="FetchUserData">
    
      
       <apex:commandButton action="{!RefreshUserData}" value="Refresh data" reRender="weatherpanel" />
      
 
        <apex:pageBlock title="User details" id="weatherpanel">
        <apex:pageBlockSection collapsible="false" title="General details" >
          <apex:outputText label="Name" value="{!UserData.results[0].name.title} {!UserData.results[0].name.first} {!UserData.results[0].name.last}">
           <apex:outputText label="Gender" value="{!UserData.results[0].gender}">  
           <apex:outputText label="Email" value="{!UserData.results[0].email}"> 
           <apex:outputText label="Phone" value="{!UserData.results[0].phone}">
            <apex:outputText label="Cell" value="{!UserData.results[0].cell}">
            <apex:outputText label="Address" value="{!UserData.results[0].location.street} {!UserData.results[0].location.city} {!UserData.results[0].location.state} {!UserData.results[0].location.postcode}">

JSON2APEX

 Json2Apex tool will help generate strongly typed Apex code for parsing a JSON structure given an example of the JSON. Using this all the manual job of creating wrapper classes can be eliminated.
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