We can generate standard JSON-encoded content, using the JSONGenerator class methods.
JSONGenerator Class Methods:
| Method | Description |
|---|---|
| close | Closes the JSON generator.No more content can be written after the JSON generator is closed. |
| getAsString | Returns the generated JSON content, and also this method closes the JSON generator if it isn’t closed already. |
| isClosed | Returns true if the JSON generator is closed; otherwise, returns false. |
| writeBlob | Writes the specified Blob value as a base64-encoded string. |
| writeBlobField | Writes a field name and value pair using the specified field name and BLOB value. |
| writeBoolean | Writes the specified Boolean value. |
| writeBooleanField | Writes a field name and value pair using the specified field name and Boolean value. |
| writeDate | Writes the specified date value in the ISO-8601 format. |
| writeDateField | Writes a field name and value pair using the specified field name and date value. The date value is written in the ISO-8601 format. |
| writeDateTime | Writes the specified date and time value in the ISO-8601 format. |
| writeDateTimeField | Writes a field name and value pair using the specified field name and date and time value. The date and time value is written in the ISO-8601 format. |
| writeEndArray | Writes the ending marker of a JSON array (‘]’). |
| writeEndObject | Writes the ending marker of a JSON object (‘}’). |
| writeFieldName | Writes a field name. |
| writeId | Writes the specified ID value. |
| writeIdField | Writes a field name and value pair using the specified field name and identifier value. |
| writeNull | Writes the JSON null literal value |
| writeNullField | Writes a field name and value pair using the specified field name and the JSON null literal value. |
| writeNumber | Writes the specified decimal, double, integer and long value. |
| writeNumberField | Writes a field name and value pair using the specified field name and decimal, double, integer, long value. |
| writeObject | Writes the specified Apex object in JSON format |
| writeObjectField | Writes a field name and value pair using the specified field name and Apex object. |
| writeStartArray | Writes the starting marker of a JSON array (‘[‘). |
| writeStartObject | Writes the starting marker of a JSON object (‘{‘). |
| writeString | Writes the specified string value. |
| writeStringField | Writes a field name and value pair using the specified field name and string value. |
| writeTime | Writes the specified time value in the ISO-8601 format. |
| writeTimeField | Writes a field name and value pair using the specified field name and time value in the ISO-8601 format. |
Example:
List<Account> accList = [SELECT Id, Name, AccountNumber, Industry From Account];
if(!accList.isEmpty()){
JSONGenerator gen = JSON.createGenerator(true);
gen.writeStartObject();
gen.writeFieldName('AccountList');
gen.writeStartArray();
for(Account acc :accList){
gen.writeStartObject();
gen.writeStringField('Id', acc.Id);
gen.writeStringField('Name', acc.Name);
gen.writeStringField('AccountNumber', acc.AccountNumber);
gen.writeStringField('Industry', acc.Industry);
gen.writeEndObject();
}
gen.writeEndArray();
gen.writeEndObject();
String jsonData = gen.getAsString();
System.debug('jsonData-' + jsonData);
}
Output:
{
"AccountList" : [ {
"Id" : "001B000000oAg2fIAC",
"Name" : "Bostonic Bulk Company",
"AccountNumber" : "232323",
"Industry" : "Technology"
}, {
"Id" : "001B000000oAg4UIAS",
"Name" : "Bitrex Bulk Company",
"AccountNumber" : "123232",
"Industry" : "Technology"
}, {
"Id" : "001B000000pA7skIAC",
"Name" : "Amazon",
"AccountNumber" : "12345",
"Industry" : "Technology"
}, {
"Id" : "001B000000pA7sVIAS",
"Name" : "Salesforce",
"AccountNumber" : "12346",
"Industry" : "Technology"
} ]
}