Apex Developer Guide

Apex Developer Guide
Getting Started with Apex
Writing Apex
Running Apex
Invoking Apex
Apex Transactions and Governor Limits
Using Salesforce Features with Apex
Integration and Apex Utilities
Invoking Callouts Using Apex
JSON Support
Roundtrip Serialization and Deserialization
JSON Generator
JSON Parsing
XML Support
Securing Your Data
Encoding Your Data
Using Patterns and Matchers
Debugging, Testing, and Deploying Apex
Apex Language Reference
Appendices
Glossary
PDF

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Roundtrip Serialization and Deserialization

Use the JSON class methods to perform roundtrip serialization and deserialization of your JSON content. These methods enable you to serialize objects into JSON-formatted strings and to deserialize JSON strings back into objects.

Example: Serialize and Deserialize a List of Invoices

This example creates a list of InvoiceStatement objects and serializes the list. Next, the serialized JSON string is used to deserialize the list again and the sample verifies that the new list contains the same invoices that were present in the original list.

JSON Serialization Considerations

The behavior of the serialize method differs depending on the Salesforce API version of the Apex code saved.

Serialization of queried sObject with additional fields set
For Apex saved using Salesforce API version 27.0 and earlier, if queried sObjects have additional fields set, these fields aren’t included in the serialized JSON string returned by the serialize method. Starting with Apex saved using Salesforce API version 28.0, the additional fields are included in the serialized JSON string.
This example adds a field to a contact after it has been queried, and then serializes the contact. The assertion statement verifies that the JSON string contains the additional field. The assertion passes for Apex saved using Salesforce API version 28.0 and later.
Serialization of aggregate query result fields
For Apex saved using Salesforce API version 27.0, results of aggregate queries don’t include the fields in the SELECT statement when serialized using the serialize method. For earlier API versions or for API version 28.0 and later, serialized aggregate query results include all fields in the SELECT statement.
This aggregate query returns two fields: the count of ID fields and the account name.
Serialization of empty fields
Starting with API version 28.0, null fields aren’t serialized and aren’t included in the JSON string, unlike in earlier versions. This change doesn’t affect deserializing JSON strings with JSON methods, such as deserialize(jsonString, apexType). This change is noticeable when you inspect the JSON string. For example:
Serialization of IDs
In API version 34.0 and earlier, ID comparison using == fails for IDs that have been through roundtrip JSON serialization and deserialization.