Force.com Apex Code Developer's Guide
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JSON Class
Contains methods for serializing Apex objects into JSON format and deserializing JSON content that
was serialized using the serialize method in this class.
Namespace
Usage
Use the methods in the System.JSON class to perform round-trip JSON serialization and deserialization of Apex objects.
JSON Methods
The following are methods for JSON. All methods are static.
createGenerator(Boolean)
Returns a new JSON generator.
Signature
public static System.JSONGenerator createGenerator(Boolean pretty)
Parameters
- pretty
- Type: Boolean
- Determines whether the JSON generator creates JSON content in pretty-print format with the content indented. Set to true to create indented content.
Return Value
Type: System.JSONGenerator
createParser(String)
Returns a new JSON parser.
Signature
public static System.JSONParser createParser(String jsonString)
Parameters
- jsonString
- Type: String
- The JSON content to parse.
Return Value
Type: System.JSONParser
deserialize(String, System.Type)
Deserializes the specified JSON string
into an Apex object of the specified type.
Signature
public static Object deserialize(String jsonString, System.Type apexType)
Parameters
- jsonString
- Type: String
- The JSON content to deserialize.
- apexType
- Type: System.Type
- The Apex type of the object that this method creates after deserializing the JSON content.
Return Value
Type: Object
Usage
If the JSON content to parse contains attributes not present in the Apex type specified in the argument, such as a missing field or object, this method ignores these attributes and parses the rest of the JSON content. However, for Apex saved using Salesforce API version 24.0 or earlier, this method throws a run-time exception for missing attributes.
Example
The following example deserializes
a Decimal value.
1Decimal n = (Decimal)JSON.deserialize(
2 '100.1', Decimal.class);
3System.assertEquals(n, 100.1);deserializeStrict(String, System.Type)
Deserializes the specified JSON string
into an Apex object of the specified type.
Signature
public static Object deserializeStrict(String jsonString, System.Type apexType)
Parameters
- jsonString
- Type: String
- The JSON content to deserialize.
- apexType
- Type: System.Type
- The Apex type of the object that this method creates after deserializing the JSON content.
Return Value
Type: Object
Usage
All attributes in the JSON string must
be present in the specified type.If the JSON content to parse contains
attributes not present in the Apex type specified in the argument, such as a missing field or object,
this method throws a run-time exception.
Example
The following example deserializes
a JSON string into an object of a user-defined type represented by
the Car class, which this
example also defines.
1swfobject.registerObject("clippy.codeblock-1", "9");public class Car {
2 public String make;
3 public String year;
4}
5
6public void parse() {
7 Car c = (Car)JSON.deserializeStrict(
8 '{"make":"SFDC","year":"2020"}',
9 Car.class);
10 System.assertEquals(c.make, 'SFDC');
11 System.assertEquals(c.year, '2020');
12}deserializeUntyped(String)
Signature
public static Object deserializeUntyped(String jsonString)
Parameters
- jsonString
- Type: String
- The JSON content to deserialize.
Return Value
Type: Object
Example
The following example deserializes a JSON representation of an appliance
object into a map that contains primitive data types and further collections
of primitive types. It then verifies the deserialized values.
1swfobject.registerObject("clippy.exUntyped", "9");String jsonInput = '{\n' +
2 ' "description" :"An appliance",\n' +
3 ' "accessories" : [ "powerCord", ' +
4 '{ "right":"door handle1", ' +
5 '"left":"door handle2" } ],\n' +
6 ' "dimensions" : ' +
7 '{ "height" : 5.5 , ' +
8 '"width" : 3.0 , ' +
9 '"depth" : 2.2 },\n' +
10 ' "type" : null,\n' +
11 ' "inventory" : 2000,\n' +
12 ' "price" : 1023.45,\n' +
13 ' "isShipped" : true,\n' +
14 ' "modelNumber" : "123"\n' +
15 '}';
16
17Map<String, Object> m =
18 (Map<String, Object>)
19 JSON.deserializeUntyped(jsonInput);
20
21System.assertEquals(
22 'An appliance', m.get('description'));
23
24List<Object> a =
25 (List<Object>)m.get('accessories');
26System.assertEquals('powerCord', a[0]);
27Map<String, Object> a2 =
28 (Map<String, Object>)a[1];
29System.assertEquals(
30 'door handle1', a2.get('right'));
31System.assertEquals(
32 'door handle2', a2.get('left'));
33
34Map<String, Object> dim =
35 (Map<String, Object>)m.get('dimensions');
36System.assertEquals(
37 5.5, dim.get('height'));
38System.assertEquals(
39 3.0, dim.get('width'));
40System.assertEquals(
41 2.2, dim.get('depth'));
42
43System.assertEquals(null, m.get('type'));
44System.assertEquals(
45 2000, m.get('inventory'));
46System.assertEquals(
47 1023.45, m.get('price'));
48System.assertEquals(
49 true, m.get('isShipped'));
50System.assertEquals(
51 '123', m.get('modelNumber'));serialize(Object)
Serializes Apex objects into JSON content.
Signature
public static String serialize(anyType object)
Parameters
- anyType
- Type: Object
- The Apex object to serialize.
Return Value
Type: String
Example
The following example serializes
a new Datetime value.
1Datetime dt = Datetime.newInstance(
2 Date.newInstance(
3 2011, 3, 22),
4 Time.newInstance(
5 1, 15, 18, 0));
6 String str = JSON.serialize(dt);
7 System.assertEquals(
8 '"2011-03-22T08:15:18.000Z"',
9 str);serializePretty(Object)
Serializes Apex objects into JSON content and generates indented content using
the pretty-print format.
Signature
public static String serializePretty(Object anyType)
Parameters
- anyType
- Type: Object
- The Apex object to serialize.
Return Value
Type: String