JSON Serialization in Liferay

Many times we have requirement to convert Liferay service response or any list into JSON object. Most of the time we are doing this manually.

	JSONArray jsonArr = JSONFactoryUtil.createJSONArray();
	for (User user : userList)
	{
	JSONObject json = JSONFactoryUtil.createJSONObject();
	json.put("name", user.getFullName());
	json.put("id", user.getUserId());
	jsonArr.put(json);
	}
	return jsonArr.toString();

view raw JSONConversion.java hosted with ❤ by GitHub

There are other ways as well by which we can convert List into JSON string.
Service builder has support for JSON  serialization,too. The json-enabled attribute of entity tag specifies whether or not the entity should be annotated for JSONserialization.
By default, if the remote-service value is true, then thejson-enabled value is true.
Column tag has the same attribute, json-enabled.
It specifies whether or not the column should be annotated for JSON serialization. By default, if the json-enabled value in the entity element is true, then the json-enabled value in the column element is true.

	<entity name="TestJSON" table="json_test" local-service="true" remote-service="false" json-enabled="true">
	<!-- PK fields -->
	<column name="keyId" type="long" primary="true" />
	<!-- Audit fields -->
	<column name="companyId" type="long" />
	<column name="groupId" type="long" />
	<!-- Other fields -->
	<column name="firstName" type="String" json-enabled="true" />
	<column name="lastName" type="String" json-enabled="true"/>
	<column name="email" type="String" json-enabled="false"/>
	<!-- Finder methods -->
	</entity>

view raw json-service.xml hosted with ❤ by GitHub

json enabled is true for enttity TestJson so all the column tags will have by default json-enabled as true.
In case if you want to exclude any property to not to appear when you serialize then you can set json-enabled as false. For email column json-enabled is set to false.


build-service and check TestJSONModelImpl class. For the field json-enabled is true you will see @JSON annotation. For excluded fields you will see @JSON(include = false) .

	@JSON(strict = true)
	public class TestJSONModelImpl extends BaseModelImpl<TestJSON>
	implements TestJSONModel {
	@JSON
	public long getKeyId() {
	return _keyId;
	}
	@JSON
	public long getCompanyId() {
	return _companyId;
	}
	@JSON
	public long getGroupId() {
	return _groupId;
	}
	@JSON
	public String getFirstName() {
	if (_firstName == null) {
	return StringPool.BLANK;
	}
	else {
	return _firstName;
	}
	}
	@JSON
	public String getLastName() {
	if (_lastName == null) {
	return StringPool.BLANK;
	}
	else {
	return _lastName;
	}
	}
	@JSON(include = false)
	public String getEmail() {
	if (_email == null) {
	return StringPool.BLANK;
	}
	else {
	return _email;
	}
	}
	}

view raw TestJSONModelImpl.java hosted with ❤ by GitHub

Now you can easily convert your list returned using Liferay services into JSON format.

JSONSerializer jsonSerializer = JSONFactoryUtil.createJSONSerializer();
String json = jsonSerializer.serialize(list);

You can also exclude fields you don't need in JSON.

Same way you can use serialize OOB data as well like user.

 List<User> userList = UserLocalServiceUtil.getUsers(-1, -1);
 String json = JSONFactoryUtil.looseSerialize(userList);

 By default collections are excluded from serialization . You can include them using below way.
 String json  = JSONFactoryUtil.looseSerialize(userList,"organizations")