My api response seems like this
{
"name": "jackson",
"age": 33,
"hobby_list": "[{\"name\":\"soccer\", \"priority\":2}, {\"name\":\"game\", \"priority\":1}, {\"name\":\"reading\", \"priority\":3}]"
}
I want to deserialize hobby_list string value as object.
class Person {
#JsonProperty("name")
private String name;
#JsonProperty("age")
private Integer age;
#JsonProperty("hobby_list")
private List<Hobby> hobbyList;
}
class Hobby(
#JsonProperty("name")
private String name;
#JsonProperty("priority")
private Integer priority;
)
It doesn't work as you know.
Caused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `java.util.ArrayList<com.joont.domain.Hobby>` out of VALUE_STRING token
What is the best practice to solve the problem?
Annotation? Configure? Custom deserializer?
You can convert them by registering custom deserializer as below:
public class PersonDeserializer extends JsonDeserializer<Person> {
#Override
public Person deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException {
ObjectCodec oc = jp.getCodec();
JsonNode node = oc.readTree(jp);
final Integer age = node.get("age").asInt();
final String name = node.get("name").asText();
final String hobbyListAsString = node.get("hobby_list").asText();
ObjectMapper mapper = new ObjectMapper();
// convert JSON array to List of objects
List<Hobby> hobbyList = Arrays.asList(mapper.readValue(hobbyListAsString, Hobby[].class));
Person person = new Person();
person.setName(name);
person.setAge(age);
person.setHobbyList(hobbyList);
return person;
}
}
and in pojo at root use annotation #JsonDeserialize(using = PersonDeserializer.class) so that above deserializer can be registered. Attaching reference below:
#JsonDeserialize(using = PersonDeserializer.class)
#Data
public class Person {
#JsonProperty("name")
private String name;
#JsonProperty("age")
private Integer age;
#JsonProperty("hobby_list")
private List<Hobby> hobbyList;
}
Then I was able to deserialize above hobby_list string to object
ObjectMapper mapper = new ObjectMapper();
Person person = mapper.readValue(content, Person.class);
System.out.println(person.getHobbyList());
I have two classes Athlete and Injury, the last one contains Athlete object, when the serialization happens I get the following JSON representation back:
{"id":X,"kindOfInjury":"...","muscle":"...","side":"...","outOfTrainig":Y,"injuryDate":"2018-Jun-02","athlete":{"id":X,"firstName":"...","lastName":"...","age":X,"email":"..."}}
I don't want to get all the information about Athlete - just an id value, like "athleteId":1, instead of getting the entire object representation.
So, I have found that I need to apply my custom Serializer which implements StdSerializer on Injury class. So this is what I got so far:
class InjurySerializer extends StdSerializer<Injury> {
public InjurySerializer() {
this(null);
}
public InjurySerializer(Class<Injury> i) {
super(i);
}
#Override
public void serialize(
Injury value, JsonGenerator jgen, SerializerProvider provider)
throws IOException, JsonProcessingException {
jgen.writeStartObject();
jgen.writeNumberField("id", value.getId());
jgen.writeStringField("kindOfInjury", value.getKindOfInjury());
jgen.writeStringField("muscle", value.getMuscle());
jgen.writeStringField("side", value.getSide());
jgen.writeNumberField("outOfTraining", value.getOutOfTraining());
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MMM-dd");
Date date = new Date();
String ourformat = formatter.format(date.getTime());
jgen.writeStringField("injuryDate", ourformat);
jgen.writeNumberField("athleteId", value.getAthlete().getId());
jgen.writeEndObject();
}
}
And the actual Injury class:
#Entity
#Table(name = "INJURY")
#JsonSerialize(using = InjurySerializer.class)
public class Injury {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "INJURY_ID")
private Long id;
#Column(name = "KIND_OF_INJURY")
private String kindOfInjury;
#Column(name = "MUSCLE")
private String muscle;
#Column(name = "SIDE")
private String side;
#Column(name = "OUT_OF_TRAINING")
private Integer outOfTraining;
#JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MMM-dd")
#Column(name = "INJURY_DATE")
private Date injuryDate;
#ManyToOne
#JoinColumn(name = "ATHLETE_ID")
private Athlete athlete;
So, this solution works, but it looks terrible...
Question is the following:
1) Is there any mechanism which provides me functionality to change the serialization of only ONE property which I really need, instead of writing all this tedious code, where the actual change is only in this line? :
jgen.writeNumberField("athleteId", value.getAthlete().getId());
2) Could you recommend me something to read about Jackson because at this point I have a little bit mess in my head about it?
Thanks for the patience and I'm looking forwards for your responses :)
You can use the Data Transfer Object (DTO) for that purposes.
Create a simple POJO like this:
public class InjuryDTO {
//all other required fields from Injury model...
#JsonProperty("athlete_id")
private Long athleteId;
}
And converter for it:
#Component
public class InjuryToDTOConverter{
public InjuryDTO convert(Injury source){
InjuryDTO target = new InjuryDTO();
BeanUtils.copyProperties(source, target); //it will copy fields with the same names
target.setAthleteId(source.getAthlete().getId());
return target;
}
}
You can use it like that:
#RestController("/injuries")
public class InjuryController {
#Autowired
private InjuryToDTOConverter converter;
#Autowired
private InjuryService injuryService;
#GetMapping
public InjuryDTO getInjury(){
Injury injury = injuryService.getInjury();
return converter.convert(injury);
}
}
The benefit of this approach is that you can have multiple DTOs for different purposes.
You might find it less tedious to use the #JsonIgnore annotation instead of writing a custom serializer. Take this example
public class Person {
private int id;
#JsonIgnore
private String first;
#JsonIgnore
private String last;
#JsonIgnore
private int age;
// getters and setters omitted
}
When Jackson serializes this class, it only includes the "id" property in the resulting JSON.
#Test
void serialize_only_includes_id() throws JsonProcessingException {
final var person = new Person();
person.setId(1);
person.setFirst("John");
person.setLast("Smith");
person.setAge(22);
final var mapper = new ObjectMapper();
final var json = mapper.writeValueAsString(person);
assertEquals("{\"id\":1}", json);
}
You can try manupulating json string using basic string replace method.
I ran your json and converted it to your desired format:
public static void main(String args[]) {
String json = "{\"id\":123,\"kindOfInjury\":\"...\",\"muscle\":\"...\",\"side\":\"...\",\"outOfTrainig\":Y,\"injuryDate\":\"2018-Jun-02\",\"athlete\":{\"id\":456,\"firstName\":\"...\",\"lastName\":\"...\",\"age\":14,\"email\":\"...\"}}";
JsonObject injury = new JsonParser().parse(json).getAsJsonObject();
JsonObject athelete = new JsonParser().parse(injury.get("athlete").toString()).getAsJsonObject();
String updateJson = injury.toString().replace(injury.get("athlete").toString(), athelete.get("id").toString());
updateJson = updateJson.replace("athlete", "athleteId");
System.out.println(updateJson);
}
output:
{"id":123,"kindOfInjury":"...","muscle":"...","side":"...","outOfTrainig":"Y","injuryDate":"2018-Jun-02","athleteId":456}
Dependency:
implementation 'com.google.code.gson:gson:2.8.5'
If you can replace with regex that will be bit more cleaner.
When I'm trying to test my Api Controller with hardcoded Object everything is fine unitil I try to add LocalDate parameter to Object.
My Test:
#RunWith(SpringRunner.class)
#WebMvcTest(ApiTransitController.class)
public class ApiTransitControllerTest {
#Autowired
private MockMvc mockMvc;
#MockBean
private TestService testService;
#MockBean
private ReportsService reportsService;
#MockBean
private TransitService transitService;
#Test
public void shouldCreateTransit() throws Exception {
Transit transit = new Transit("London", "Paris", 12L,
LocalDate.of(2018,10,12));
ObjectMapper objectMapper = new ObjectMapper();
String transitJsonString = objectMapper.writeValueAsString(transit);
this.mockMvc.perform(post("/api/transit")
.contentType(MediaType.APPLICATION_JSON)
.content(transitJsonString))
.andExpect(status().isCreated());
verify(transitService).addTransit(eq(new Transit("London", "Paris", 12L,
LocalDate.of(2018,10,12))));
}
}
Model:
#Entity
public class Transit {
#Column(name = "id")
#Id
#GeneratedValue
private Long id;
private String sourceAdress;
private String destinationAdress;
private Long price;
#DateTimeFormat(iso = DateTimeFormat.ISO.DATE)
private LocalDate date;
#JsonSerialize(using=DistanceSerializer.class)
private Long distance;
public Transit(String sourceAdress, String destinationAdress, Long price, LocalDate date) {
this.sourceAdress = sourceAdress;
this.destinationAdress = destinationAdress;
this.price = price;
this.date = date;
}
//getters and setters, equals and hashCode and toString
Api Controller:
#PostMapping("/api/transit")
#ResponseStatus(HttpStatus.CREATED)
public void createTransit(#RequestBody Transit transit){
LOG.info("Saving transit={}", transit);
transitService.addTransit(transit);
}
I tried adding DateTimeFormmater and few other ways, but still I cant pass the test. Thank you for your time.
Try changing this line
verify(transitService).addTransit(eq(new Transit("London", "Paris", 12L,
LocalDate.of(2018,10,12))));
to this:
verify(transitService).addTransit(eq(transit));
The two objects aren't equal, also you don't need to create a new object you can use already created one.
I added JsonSerializer to date of the Model:
Model:
#DateTimeFormat(iso = DateTimeFormat.ISO.DATE)
#JsonSerialize(using=DateSerializerNumberTwo.class)
private LocalDate date;
Serializer:
public class DateSerializerNumberTwo extends StdSerializer<LocalDate> {
private static DateTimeFormatter formatter =
DateTimeFormatter.ofPattern("yyyy-MM-dd");
public DateSerializerNumberTwo(){
this(null);
}
protected DateSerializerNumberTwo(Class<LocalDate> t){
super(t);
}
#Override
public void serialize(LocalDate value, JsonGenerator gen, SerializerProvider provider) throws IOException {
gen.writeString(formatter.format(value));
}
}
And the test passes without any changes in the test code. I think it's beacuse the Json default response of date is "yyyy, mm, dd", not like Local date (yyyy-mm-dd)".
I like to deserialize with Jackson an empty String member ("") to null. The Deserialization Feature "ACCEPT_EMPTY_STRING_AS_NULL_OBJECT" can for this unfortunately not be used (see link).
#JsonIgnoreProperties(ignoreUnknown = true)
#JsonInclude(Include.NON_NULL)
public class Supplier {
private Integer id;
private String name;
private String image;
private String link;
private String description;
}
So after deserialization of the following JSON String the string members "link" and "image" should be null and not "".
{"id":37,"name":"Life","image":"","link":"","description":null}
I am looking for a way to write an own deserializer which can be used for String members of a POJO. Is there a way to achieve this? I am using faster Jackson 2.6.0.
The custom deserializer can be done as follows in Jackson 2.6.0.
public class SupplierDeserializer extends JsonDeserializer<Supplier> {
#Override
public Supplier deserialize(JsonParser jp, DeserializationContext context) throws IOException, JsonProcessingException {
Supplier sup = new Supplier();
JsonNode node = jp.readValueAsTree();
sup.setId(node.get("id").asInt());
sup.setDescription(node.get("description").asText());
String image = node.get("image").asText();
if("".equals(image)) {
image = null;
}
sup.setImage(image);
String link = node.get("link").asText();
if("".equals(link)) {
link = null;
}
sup.setLink(link);
sup.setName(node.get("name").asText());
return sup;
}
}
Register the custom deserialiser with the Supplier class
#JsonDeserialize(using = SupplierDeserializer.class)
public class Supplier {
private Integer id;
private String name;
private String image;
private String link;
private String description;
// getters and setters
}
Call the ObjectMapper class to parse the JSON data
String jsonData = "{\"id\":37,\"name\":\"Life\",\"image\":\"\",\"link\":\"\",\"description\":null}";
Supplier sup = new ObjectMapper().readValue(jsonData, Supplier.class);
I have model class like this, for hibernate
#Entity
#Table(name = "user", catalog = "userdb")
#JsonIgnoreProperties(ignoreUnknown = true)
public class User implements java.io.Serializable {
private Integer userId;
private String userName;
private String emailId;
private String encryptedPwd;
private String createdBy;
private String updatedBy;
#Id
#GeneratedValue(strategy = IDENTITY)
#Column(name = "UserId", unique = true, nullable = false)
public Integer getUserId() {
return this.userId;
}
public void setUserId(Integer userId) {
this.userId = userId;
}
#Column(name = "UserName", length = 100)
public String getUserName() {
return this.userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
#Column(name = "EmailId", nullable = false, length = 45)
public String getEmailId() {
return this.emailId;
}
public void setEmailId(String emailId) {
this.emailId = emailId;
}
#Column(name = "EncryptedPwd", length = 100)
public String getEncryptedPwd() {
return this.encryptedPwd;
}
public void setEncryptedPwd(String encryptedPwd) {
this.encryptedPwd = encryptedPwd;
}
public void setCreatedBy(String createdBy) {
this.createdBy = createdBy;
}
#Column(name = "UpdatedBy", length = 100)
public String getUpdatedBy() {
return this.updatedBy;
}
public void setUpdatedBy(String updatedBy) {
this.updatedBy = updatedBy;
}
}
In Spring MVC controller, using DAO, I am able to get the object. and returning as JSON Object.
#Controller
public class UserController {
#Autowired
private UserService userService;
#RequestMapping(value = "/getUser/{userId}", method = RequestMethod.GET)
#ResponseBody
public User getUser(#PathVariable Integer userId) throws Exception {
User user = userService.get(userId);
user.setCreatedBy(null);
user.setUpdatedBy(null);
return user;
}
}
View part is done using AngularJS, so it will get JSON like this
{
"userId" :2,
"userName" : "john",
"emailId" : "john#gmail.com",
"encryptedPwd" : "Co7Fwd1fXYk=",
"createdBy" : null,
"updatedBy" : null
}
If I don't want to set encrypted Password, I will set that field also as null.
But I don't want like this, I dont want to send all fields to client side. If I dont want password, updatedby, createdby fields to send, My result JSON should be like
{
"userId" :2,
"userName" : "john",
"emailId" : "john#gmail.com"
}
The list of fields which I don't want to send to client coming from other database table. So it will change based on the user who is logged in. How can I do that?
I hope You got my question.
Add the #JsonIgnoreProperties("fieldname") annotation to your POJO.
Or you can use #JsonIgnore before the name of the field you want to ignore while deserializing JSON. Example:
#JsonIgnore
#JsonProperty(value = "user_password")
public String getUserPassword() {
return userPassword;
}
GitHub example
Can I do it dynamically?
Create view class:
public class View {
static class Public { }
static class ExtendedPublic extends Public { }
static class Internal extends ExtendedPublic { }
}
Annotate you model
#Document
public class User {
#Id
#JsonView(View.Public.class)
private String id;
#JsonView(View.Internal.class)
private String email;
#JsonView(View.Public.class)
private String name;
#JsonView(View.Public.class)
private Instant createdAt = Instant.now();
// getters/setters
}
Specify the view class in your controller
#RequestMapping("/user/{email}")
public class UserController {
private final UserRepository userRepository;
#Autowired
UserController(UserRepository userRepository) {
this.userRepository = userRepository;
}
#RequestMapping(method = RequestMethod.GET)
#JsonView(View.Internal.class)
public #ResponseBody Optional<User> get(#PathVariable String email) {
return userRepository.findByEmail(email);
}
}
Data example:
{"id":"5aa2496df863482dc4da2067","name":"test","createdAt":"2018-03-10T09:35:31.050353800Z"}
UPD: keep in mind that it's not best practice to use entity in response. Better use different DTO for each case and fill them using modelmapper
I know I'm a bit late to the party, but I actually ran into this as well a few months back. All of the available solutions weren't very appealing to me (mixins? ugh!), so I ended up creating a new library to make this process cleaner. It's available here if anyone would like to try it out: https://github.com/monitorjbl/spring-json-view.
The basic usage is pretty simple, you use the JsonView object in your controller methods like so:
import com.monitorjbl.json.JsonView;
import static com.monitorjbl.json.Match.match;
#RequestMapping(method = RequestMethod.GET, value = "/myObject")
#ResponseBody
public void getMyObjects() {
//get a list of the objects
List<MyObject> list = myObjectService.list();
//exclude expensive field
JsonView.with(list).onClass(MyObject.class, match().exclude("contains"));
}
You can also use it outside of Spring:
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import static com.monitorjbl.json.Match.match;
ObjectMapper mapper = new ObjectMapper();
SimpleModule module = new SimpleModule();
module.addSerializer(JsonView.class, new JsonViewSerializer());
mapper.registerModule(module);
mapper.writeValueAsString(JsonView.with(list)
.onClass(MyObject.class, match()
.exclude("contains"))
.onClass(MySmallObject.class, match()
.exclude("id"));
Yes, you can specify which fields are serialized as JSON response and which to ignore.
This is what you need to do to implement Dynamically ignore properties.
1) First, you need to add #JsonFilter from com.fasterxml.jackson.annotation.JsonFilter on your entity class as.
import com.fasterxml.jackson.annotation.JsonFilter;
#JsonFilter("SomeBeanFilter")
public class SomeBean {
private String field1;
private String field2;
private String field3;
// getters/setters
}
2) Then in your controller, you have to add create the MappingJacksonValue object and set filters on it and in the end, you have to return this object.
import java.util.Arrays;
import java.util.List;
import org.springframework.http.converter.json.MappingJacksonValue;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import com.fasterxml.jackson.databind.ser.FilterProvider;
import com.fasterxml.jackson.databind.ser.impl.SimpleBeanPropertyFilter;
import com.fasterxml.jackson.databind.ser.impl.SimpleFilterProvider;
#RestController
public class FilteringController {
// Here i want to ignore all properties except field1,field2.
#GetMapping("/ignoreProperties")
public MappingJacksonValue retrieveSomeBean() {
SomeBean someBean = new SomeBean("value1", "value2", "value3");
SimpleBeanPropertyFilter filter = SimpleBeanPropertyFilter.filterOutAllExcept("field1", "field2");
FilterProvider filters = new SimpleFilterProvider().addFilter("SomeBeanFilter", filter);
MappingJacksonValue mapping = new MappingJacksonValue(someBean);
mapping.setFilters(filters);
return mapping;
}
}
This is what you will get in response:
{
field1:"value1",
field2:"value2"
}
instead of this:
{
field1:"value1",
field2:"value2",
field3:"value3"
}
Here you can see it ignores other properties(field3 in this case) in response except for property field1 and field2.
Hope this helps.
We can do this by setting access to JsonProperty.Access.WRITE_ONLY while declaring the property.
#JsonProperty( value = "password", access = JsonProperty.Access.WRITE_ONLY)
#SerializedName("password")
private String password;
Add #JsonInclude(JsonInclude.Include.NON_NULL) (forces Jackson to serialize null values) to the class as well as #JsonIgnore to the password field.
You could of course set #JsonIgnore on createdBy and updatedBy as well if you always want to ignore then and not just in this specific case.
UPDATE
In the event that you do not want to add the annotation to the POJO itself, a great option is Jackson's Mixin Annotations. Check out the documentation
I've solved using only #JsonIgnore like #kryger has suggested.
So your getter will become:
#JsonIgnore
public String getEncryptedPwd() {
return this.encryptedPwd;
}
You can set #JsonIgnore of course on field, setter or getter like described here.
And, if you want to protect encrypted password only on serialization side (e.g. when you need to login your users), add this #JsonProperty annotation to your field:
#JsonProperty(access = Access.WRITE_ONLY)
private String encryptedPwd;
More info here.
If I were you and wanted to do so, I wouldn't use my User entity in Controller layer.Instead I create and use UserDto (Data transfer object) to communicate with business(Service) layer and Controller.
You can use Apache BeanUtils(copyProperties method) to copy data from User entity to UserDto.
I have created a JsonUtil which can be used to ignore fields at runtime while giving a response.
Example Usage :
First argument should be any POJO class (Student) and ignoreFields is comma seperated fields you want to ignore in response.
Student st = new Student();
createJsonIgnoreFields(st,"firstname,age");
import java.util.logging.Logger;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.ObjectWriter;
import org.codehaus.jackson.map.ser.FilterProvider;
import org.codehaus.jackson.map.ser.impl.SimpleBeanPropertyFilter;
import org.codehaus.jackson.map.ser.impl.SimpleFilterProvider;
public class JsonUtil {
public static String createJsonIgnoreFields(Object object, String ignoreFields) {
try {
ObjectMapper mapper = new ObjectMapper();
mapper.getSerializationConfig().addMixInAnnotations(Object.class, JsonPropertyFilterMixIn.class);
String[] ignoreFieldsArray = ignoreFields.split(",");
FilterProvider filters = new SimpleFilterProvider()
.addFilter("filter properties by field names",
SimpleBeanPropertyFilter.serializeAllExcept(ignoreFieldsArray));
ObjectWriter writer = mapper.writer().withFilters(filters);
return writer.writeValueAsString(object);
} catch (Exception e) {
//handle exception here
}
return "";
}
public static String createJson(Object object) {
try {
ObjectMapper mapper = new ObjectMapper();
ObjectWriter writer = mapper.writer().withDefaultPrettyPrinter();
return writer.writeValueAsString(object);
}catch (Exception e) {
//handle exception here
}
return "";
}
}
I've found a solution for me with Spring and jackson
First specify the filter name in the entity
#Entity
#Table(name = "SECTEUR")
#JsonFilter(ModelJsonFilters.SECTEUR_FILTER)
public class Secteur implements Serializable {
/** Serial UID */
private static final long serialVersionUID = 5697181222899184767L;
/**
* Unique ID
*/
#Id
#JsonView(View.SecteurWithoutChildrens.class)
#Column(name = "id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
#JsonView(View.SecteurWithoutChildrens.class)
#Column(name = "code", nullable = false, length = 35)
private String code;
/**
* Identifiant du secteur parent
*/
#JsonView(View.SecteurWithoutChildrens.class)
#Column(name = "id_parent")
private Long idParent;
#OneToMany(fetch = FetchType.LAZY)
#JoinColumn(name = "id_parent")
private List<Secteur> secteursEnfants = new ArrayList<>(0);
}
Then you can see the constants filters names class with the default FilterProvider used in spring configuration
public class ModelJsonFilters {
public final static String SECTEUR_FILTER = "SecteurFilter";
public final static String APPLICATION_FILTER = "ApplicationFilter";
public final static String SERVICE_FILTER = "ServiceFilter";
public final static String UTILISATEUR_FILTER = "UtilisateurFilter";
public static SimpleFilterProvider getDefaultFilters() {
SimpleBeanPropertyFilter theFilter = SimpleBeanPropertyFilter.serializeAll();
return new SimpleFilterProvider().setDefaultFilter(theFilter);
}
}
Spring configuration :
#EnableWebMvc
#Configuration
#ComponentScan(basePackages = "fr.sodebo")
public class ApiRootConfiguration extends WebMvcConfigurerAdapter {
#Autowired
private EntityManagerFactory entityManagerFactory;
/**
* config qui permet d'éviter les "Lazy loading Error" au moment de la
* conversion json par jackson pour les retours des services REST<br>
* on permet à jackson d'acceder à sessionFactory pour charger ce dont il a
* besoin
*/
#Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
super.configureMessageConverters(converters);
MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
ObjectMapper mapper = new ObjectMapper();
// config d'hibernate pour la conversion json
mapper.registerModule(getConfiguredHibernateModule());//
// inscrit les filtres json
subscribeFiltersInMapper(mapper);
// config du comportement de json views
mapper.configure(MapperFeature.DEFAULT_VIEW_INCLUSION, false);
converter.setObjectMapper(mapper);
converters.add(converter);
}
/**
* config d'hibernate pour la conversion json
*
* #return Hibernate5Module
*/
private Hibernate5Module getConfiguredHibernateModule() {
SessionFactory sessionFactory = entityManagerFactory.unwrap(SessionFactory.class);
Hibernate5Module module = new Hibernate5Module(sessionFactory);
module.configure(Hibernate5Module.Feature.FORCE_LAZY_LOADING, true);
return module;
}
/**
* inscrit les filtres json
*
* #param mapper
*/
private void subscribeFiltersInMapper(ObjectMapper mapper) {
mapper.setFilterProvider(ModelJsonFilters.getDefaultFilters());
}
}
Endly I can specify a specific filter in restConstoller when i need....
#RequestMapping(value = "/{id}/droits/", method = RequestMethod.GET)
public MappingJacksonValue getListDroits(#PathVariable long id) {
LOGGER.debug("Get all droits of user with id {}", id);
List<Droit> droits = utilisateurService.findDroitsDeUtilisateur(id);
MappingJacksonValue value;
UtilisateurWithSecteurs utilisateurWithSecteurs = droitsUtilisateur.fillLists(droits).get(id);
value = new MappingJacksonValue(utilisateurWithSecteurs);
FilterProvider filters = ModelJsonFilters.getDefaultFilters().addFilter(ModelJsonFilters.SECTEUR_FILTER, SimpleBeanPropertyFilter.serializeAllExcept("secteursEnfants")).addFilter(ModelJsonFilters.APPLICATION_FILTER,
SimpleBeanPropertyFilter.serializeAllExcept("services"));
value.setFilters(filters);
return value;
}
Place #JsonIgnore on the field or its getter, or create a custom dto
#JsonIgnore
private String encryptedPwd;
or as mentioned above by ceekay annotate it with #JsonProperty where access attribute is set to write only
#JsonProperty( value = "password", access = JsonProperty.Access.WRITE_ONLY)
private String encryptedPwd;
Can I do it dynamically?
Yes, you can use a combination of Jackson's PropertyFilter and mixins.
Explanation
Jackson has a PropertyFilter interface to implement a filter to ignore fields dynamically. The problem is that filter has to be defined on the DTO/POJO class using the #JsonFilter annotation.
To avoid adding a #JsonFilter on class we can use ObjectMapper's addMixIn method to "dynamically" add this annotation (and leave our DTO/POJO classes as is).
Code example
Here is my implementation of the idea provided above. We can call toJson() with two arguments: (1) object to be serialized and (2) lambda (Java's Predicate) to be used in PropertyFilter:
public class JsonService {
public String toJson(Object object, Predicate<PropertyWriter> filter) {
ObjectMapper mapper = new ObjectMapper();
FilterProvider filterProvider = new SimpleFilterProvider()
.addFilter("DynamicFilter", new DynamicFilter(filter));
mapper.setFilterProvider(filterProvider);
mapper.addMixIn(object.getClass(), DynamicFilterMixin.class);
try {
return mapper.writeValueAsString(object);
} catch (JsonProcessingException e) {
throw new MyException(e);
}
}
private static final class DynamicFilter extends SimpleBeanPropertyFilter {
private Predicate<PropertyWriter> filter;
private DynamicFilter(Predicate<PropertyWriter> filter) {
this.filter = filter;
}
protected boolean include(BeanPropertyWriter writer) {
return include((PropertyWriter) writer);
}
protected boolean include(PropertyWriter writer) {
return filter.test(writer);
}
}
#JsonFilter("DynamicFilter")
private interface DynamicFilterMixin {
}
}
Now we can call toJson and filter fields during a serialization:
Filtering by name
new JsonService().toJson(object, w -> !w.getName().equals("fieldNameToBeIgnored"));
Filtering by annotation (on the field)
new JsonService().toJson(object, w -> w.getAnnotation(MyAnnotation.class) == null);
Unit tests
Here are the unit tests for the class above:
public class JsonServiceTest {
private JsonService jsonService = new JsonService();
#Test
public void withoutFiltering() {
MyObject object = getObject();
String json = jsonService.toJson(object, w -> true);
assertEquals("{\"myString\":\"stringValue\",\"myInteger\":10,\"myBoolean\":true}", json);
}
#Test
public void filteredByFieldName() {
MyObject object = getObject();
String json = jsonService.toJson(object, w -> !w.getName().equals("myString"));
assertEquals("{\"myInteger\":10,\"myBoolean\":true}", json);
}
#Test
public void filteredByAnnotation() {
MyObject object = getObject();
String json = jsonService.toJson(object, w -> w.getAnnotation(Deprecated.class) == null);
assertEquals("{\"myString\":\"stringValue\",\"myInteger\":10}", json);
}
private MyObject getObject() {
MyObject object = new MyObject();
object.myString = "stringValue";
object.myInteger = 10;
object.myBoolean = true;
return object;
}
private static class MyObject {
private String myString;
private int myInteger;
#Deprecated
private boolean myBoolean;
public String getMyString() {
return myString;
}
public void setMyString(String myString) {
this.myString = myString;
}
public int getMyInteger() {
return myInteger;
}
public void setMyInteger(int myInteger) {
this.myInteger = myInteger;
}
public boolean isMyBoolean() {
return myBoolean;
}
public void setMyBoolean(boolean myBoolean) {
this.myBoolean = myBoolean;
}
}
}
Would not creating a UserJsonResponse class and populating with the wanted fields be a cleaner solution?
Returning directly a JSON seems a great solution when you want to give all the model back. Otherwise it just gets messy.
In the future, for example you might want to have a JSON field that does not match any Model field and then you're in a bigger trouble.
This is a clean utility tool for the above answer :
#GetMapping(value = "/my-url")
public #ResponseBody
MappingJacksonValue getMyBean() {
List<MyBean> myBeans = Service.findAll();
MappingJacksonValue mappingValue = MappingFilterUtils.applyFilter(myBeans, MappingFilterUtils.JsonFilterMode.EXCLUDE_FIELD_MODE, "MyFilterName", "myBiggerObject.mySmallerObject.mySmallestObject");
return mappingValue;
}
//AND THE UTILITY CLASS
public class MappingFilterUtils {
public enum JsonFilterMode {
INCLUDE_FIELD_MODE, EXCLUDE_FIELD_MODE
}
public static MappingJacksonValue applyFilter(Object object, final JsonFilterMode mode, final String filterName, final String... fields) {
if (fields == null || fields.length == 0) {
throw new IllegalArgumentException("You should pass at least one field");
}
return applyFilter(object, mode, filterName, new HashSet<>(Arrays.asList(fields)));
}
public static MappingJacksonValue applyFilter(Object object, final JsonFilterMode mode, final String filterName, final Set<String> fields) {
if (fields == null || fields.isEmpty()) {
throw new IllegalArgumentException("You should pass at least one field");
}
SimpleBeanPropertyFilter filter = null;
switch (mode) {
case EXCLUDE_FIELD_MODE:
filter = SimpleBeanPropertyFilter.serializeAllExcept(fields);
break;
case INCLUDE_FIELD_MODE:
filter = SimpleBeanPropertyFilter.filterOutAllExcept(fields);
break;
}
FilterProvider filters = new SimpleFilterProvider().addFilter(filterName, filter);
MappingJacksonValue mapping = new MappingJacksonValue(object);
mapping.setFilters(filters);
return mapping;
}
}
To acheive dynamic filtering follow the link - https://iamvickyav.medium.com/spring-boot-dynamically-ignore-fields-while-converting-java-object-to-json-e8d642088f55
Add the #JsonFilter("Filter name") annotation to the model class.
Inside the controller function add the code:-
SimpleBeanPropertyFilter simpleBeanPropertyFilter =
SimpleBeanPropertyFilter.serializeAllExcept("id", "dob");
FilterProvider filterProvider = new SimpleFilterProvider()
.addFilter("Filter name", simpleBeanPropertyFilter);
List<User> userList = userService.getAllUsers();
MappingJacksonValue mappingJacksonValue = new MappingJacksonValue(userList);
mappingJacksonValue.setFilters(filterProvider);
return mappingJacksonValue;
make sure the return type is MappingJacksonValue.
Hi I have achieved dynamic filtering by using Gson library like in the below:
JsonObject jsonObj = new Gson().fromJson(mapper.writeValueAsString(sampleObject), JsonObject.class);
jsonObj.remove("someProperty");
String data = new Gson().toJson(jsonObj);
In your entity class add #JsonInclude(JsonInclude.Include.NON_NULL) annotation to resolve the problem
it will look like
#Entity
#JsonInclude(JsonInclude.Include.NON_NULL)