Force.com Apex Code Developer's Guide
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JSON Generator
Using the JSONGenerator class methods, you can generate standard JSON-encoded content.
You can construct JSON content, element by element, using the standard JSON encoding. To do so, use the methods in the JSONGenerator class.
JSONGenerator Sample
This example generates a JSON string in pretty print format by using the methods of the JSONGenerator class. The example first adds a number field and a string field, and then adds a field to contain an object field of a list of integers, which gets deserialized properly. Next, it adds the A object into the Object A field, which also gets deserialized.
1swfobject.registerObject("clippy.codeblock-0", "9");
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17public class JSONGeneratorSample{
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19 public class A {
20 String str;
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22 public A(String s) { str = s; }
23 }
24
25 static void generateJSONContent() {
26 // Create a JSONGenerator object.
27 // Pass true to the constructor for pretty print formatting.
28 JSONGenerator gen = JSON.createGenerator(true);
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30 // Create a list of integers to write to the JSON string.
31 List<integer> intlist = new List<integer>();
32 intlist.add(1);
33 intlist.add(2);
34 intlist.add(3);
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36 // Create an object to write to the JSON string.
37 A x = new A('X');
38
39 // Write data to the JSON string.
40 gen.writeStartObject();
41 gen.writeNumberField('abc', 1.21);
42 gen.writeStringField('def', 'xyz');
43 gen.writeFieldName('ghi');
44 gen.writeStartObject();
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46 gen.writeObjectField('aaa', intlist);
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48 gen.writeEndObject();
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50 gen.writeFieldName('Object A');
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52 gen.writeObject(x);
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54 gen.writeEndObject();
55
56 // Get the JSON string.
57 String pretty = gen.getAsString();
58
59 System.assertEquals('{\n' +
60 ' "abc" : 1.21,\n' +
61 ' "def" : "xyz",\n' +
62 ' "ghi" : {\n' +
63 ' "aaa" : [ 1, 2, 3 ]\n' +
64 ' },\n' +
65 ' "Object A" : {\n' +
66 ' "str" : "X"\n' +
67 ' }\n' +
68 '}', pretty);
69 }
70}