How to read values from nested JSON using Apex?

Question

I'm passing a JSON string from Javascript to Apex. The fields I want to access are "Name" and "Content_Copy__c" for each instance of "fields", but I can't seem to figure it out. Part of me thinks I need to create a map of the map, but I'm also unsure how to do that. In the try-catch, the try does not work, and I think that is part of the problem as it goes into the catch.

String jsonListString = '[{"fields":{"Name":"Step 1","Content_Copy__c":"lorem"}},{"fields":{"Name":"Step 2","Content_Copy__c":"ipsum"}}]';
Object o = JSON.deserializeUntyped(jsonListString);
try{
    Map<String, Object> m = (Map<String, Object>) o;
    System.debug('The Map is: ' + m);
}
catch(TypeException e){
    List<Object> a = (List<Object>) o;   
    for(Object obj : a){
        Map<String, Object> mapObject = (Map<String, Object>) obj;
        Object s = mapObject.get('fields');
        System.debug(s);
    }
}

The above code gives the following results when printed to the debugger.

EDIT: with @Moustafa Ishak 's suggestion, I've changed things around to be like so:

public class fields{
    public String Name {get; set;}
    public String Content_Copy {get; set;}

    public fields(String Name, String Content_Copy){
        this.Name = Name;
        this.Content_Copy = Content_Copy;
    }
}

String jsonListString = '[{"fields":{"Name":"Step 1","Content_Copy":"lorem"}},{"fields":{"Name":"Step 2","Content_Copy":"ipsum"}}]';
List<fields> response = (List<fields>)System.JSON.deserialize(jsonListString, List<fields>.class);
for(fields f : response){
    System.debug('Name: ' + f.Name);
    System.debug('Content_Copy: ' + f.Content_Copy);
}

Which gives me null values as shown below. I had to change "Content_Copy__c" to "Content_Copy" since Apex has a problem with non-custom object ending in "__c". That won't be an issue once I get the values of the fields. The code above recognized if I add or take away another "fields" entry, but won't recognize the values of "Name" and "Content_Copy".

Moustafa Ishak · Accepted Answer · 2020-08-17 02:09:44Z

1

Can you try to create response wrapper as below

public class response{
public String Name {get; set;}
public String Content_Copy {get; set;}

public response(String Name, String Content_Copy){
    this.Name = Name;
    this.Content_Copy = Content_Copy;
}


public class responseWrapper{

public response fields {get; set;}

}

}

then you can use the standard JSON.deserialize to get a list of the response wrapper (fields)

String jsonListString = '[{"fields":{"Name":"Step 1","Content_Copy":"lorem"}},{"fields":{"Name":"Step 2","Content_Copy":"ipsum"}}]';
List<response.responseWrapper> response = (List<response.responseWrapper>)System.JSON.deserialize(jsonListString, 
List<response.responseWrapper>.class);
system.debug('response ' +response);
for(response.responseWrapper f : response){
System.debug('fileds: ' + f.fields);
System.debug('name: ' + f.fields.name);
System.debug('Content_Copy: ' + f.fields.Content_Copy);
}

edited Aug 17, 2020 at 2:09

answered Aug 17, 2020 at 0:26

Moustafa Ishak

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2 Comments

ThatBrayKid Over a year ago

I followed your suggestion but am just getting 'null' for both values. I've edited my original post to show that.

Moustafa Ishak Over a year ago

@ThatBrayKid I have update the answer it should be working now

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