I'm trying to extract API data from the Json file below.
I want to retrieve the "name" of each "item".
Once the "name" is retrieved, I want to create a new Json that will contain :
{name: "toto", name: "titi"....}
The goal is then to create an API on my side which on a call from http://localhost/getitems will return the result of the Json created.
I'm new to Java and Spring Boot, so if you think there is a code that is easier, let me know, i hope you can help me to create that new Json file easily. Thanks !
// Json File (it has been reduced, more than 700 name are present)
{
"kind": "Space",
"apiVersion": "v1",
"metadata": {
"selfLink": "something",
"resourceVersion": "something"
},
"items": [
{
"metadata": {
"name": "projet1"
}
},
{
"metadata": {
"name": "com-cicd"
}
}
]
}
// TestGet.java Class
public static NameSpaceJson getPostWithCustomHeaders(String DebutUrl, String MilieuUrl, String ParamUrl) {
String url = DebutUrl.concat(MilieuUrl).concat(ParamUrl);
String Bearer = "...";
// create headers & template
HttpHeaders headers = new HttpHeaders();
RestTemplate restTemplate = new RestTemplate();
// set `accept` header for the type of response
headers.setAccept(Collections.singletonList(MediaType.APPLICATION_JSON));
// set custom header, bearer here too
headers.set("x-request-source", "desktop");
headers.set("Authorization", "Bearer "+Bearer);
// build the request
#SuppressWarnings({ "rawtypes", "unchecked" })
HttpEntity request = new HttpEntity(headers);
// use `exchange` method for HTTP call, this one permits us to use bearer for auth
ResponseEntity<NameSpaceJson> response = restTemplate.exchange(url, HttpMethod.GET, request, NameSpaceJson.class, 1);
if(response.getStatusCode() == HttpStatus.OK) {
return response.getBody();
} else {
return null;
}
}
// The name in the same file
public static void main(String[] args) {
TestGet.disableSSLCertificateChecking();
NameSpaceJson resultresponse = getPostWithCustomHeaders("https...","api","names");
// Long response = resultresponse.getValue().getId();
List<Item> response = resultresponse.getItems();
String test = GenerateNewJsonNameSpace.createJsonContent(response);
System.out.println(test);
}
//NameSpaceJson.java File
package com.example.consumingrest;
import java.util.List;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
#JsonIgnoreProperties(ignoreUnknown = true)
public class NameSpaceJson {
private String kind;
private String apiVersion;
private List<Item> items;
public String getKind() {
return kind;
}
public void setKind(String kind) {
this.kind = kind;
}
public String getApiVersion() {
return apiVersion;
}
public void setApiVersion(String apiVersion) {
this.apiVersion = apiVersion;
}
public List<Item> getItems() {
return items;
}
public void setItems(List<Item> items) {
this.items = items;
}
}
//Metadata.java
package com.example.consumingrest;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
#JsonIgnoreProperties(ignoreUnknown = true)
public class Metadata {
private String name;
private String creationTimestamp;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCreationTimestamp() {
return creationTimestamp;
}
public void setCreationTimestamp(String creationTimestamp) {
this.creationTimestamp = creationTimestamp;
}
}
//Item.java
package com.example.consumingrest;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
#JsonIgnoreProperties(ignoreUnknown = true)
public class Item {
Metadata metadata;
public Metadata getMetadata() {
return metadata;
}
public void setMetadata(Metadata metadata) {
this.metadata = metadata;
}
}
// GenerateNewJsonNameSpace ( this is what i have tried.. but i'm sure we can do really better.. )
package com.example.consumingrest;
import java.util.List;
public class GenerateNewJsonNameSpace {
public static String createJsonContent(List<Item> ListOfNameSpace) {
if(ListOfNameSpace.isEmpty()) {
return null;
}else {
String LeJson;
LeJson = "{";
for(int i = 0; i < ListOfNameSpace.size(); i++) {
LeJson.concat(ListOfNameSpace.get(i).getMetadata().getName());
LeJson.concat(", \n");
}
LeJson.concat("}");
return LeJson;
}
}
}
you can use a library named Gson, which is created by google specifically for handling the JSON data.
All you need to do is create a new Gson object and parse the JSON with it.
You can do in just couple of lines
String jsonString = "{ \"kind\": \"Space\", \"apiVersion\": \"v1\", \"metadata\": { \"selfLink\": \"something\", \"resourceVersion\": \"something\" }, \"items\": [ { \"metadata\": { \"name\": \"projet1\" } }, { \"metadata\": { \"name\": \"affeccom-cicd\" } } ] }";
JsonObject data = new Gson().fromJson(jsonString, JsonObject.class);
JsonArray names = data .get("items").getAsJsonArray();
for(JsonElement element : names){
JsonObject object = element.getAsJsonObject();
System.out.println(object.get("metadata").getAsJsonObject().get("name").getAsString());
}
I have an endpoint in spring boot that consumes this JSON as an example:
{
"userId": 3,
"postBody": "This is the body of a post",
"postTitle": "This is the title of a post",
"created": null,
"tagList": ["tag1", "tag2", "tag3"]
}
The endpoint:
#RequestMapping(value="/newPost", method = RequestMethod.POST, produces="application/json", consumes = "application/json")
#ResponseBody
public ResponseEntity newPost(#RequestBody Map<String, Object> body) throws Exception {
I know the issue here is the Request body is being saved as a Map of objects which is fine for all the other attributes except the tagList. How can I get tagList to be an array of Strings in Java?
Thanks.
A mixutre of Ankur and Jose's answers solved this, thanks for the fast responses guys!
You should probably create a Java class which represents the input JSON and use it in the method newPost(.....). For example:-
public class UserPostInfo {
private int userId;
private String postBody;
private String postTitle;
private Date created;
private List<String> tagList;
}
Also, include the getter/setter methods in this class.
If you want to modify the behavior of JSON parsing, you can use Annotations to change field names, include only non-null values, and stuff like this.
If you don't want to use a custom POJO you could also just handle the deserialization into a Map yourself. Just have your controller accept a String and then use Jackson's ObjectMapper along with TypeReference to get a map.
#RequestMapping(value="/newPost", method = RequestMethod.POST, produces="application/json", consumes = "application/json")
#ResponseBody
public ResponseEntity newPost(#RequestBody String body) throws Exception {
ObjectMapper mapper = new ObjectMapper();
TypeReference<HashMap<String,Object>> typeRef = new TypeReference<HashMap<String,Object>>() {};
HashMap<String,Object> map = mapper.readValue(body, typeRef);
}
The resulting HashMap will use an ArrayList for the tag list:
You can create a custom Java POJO for the request that uses String[] versus List<String>. Here I did it for you using the site jsonschema2pojo.
package com.stackoverflow.question;
import com.fasterxml.jackson.annotation.*;
import java.util.HashMap;
import java.util.Map;
#JsonInclude(JsonInclude.Include.NON_NULL)
#JsonPropertyOrder({
"userId",
"postBody",
"postTitle",
"created",
"tagList"
})
public class MyRequest {
#JsonProperty("userId")
private int userId;
#JsonProperty("postBody")
private String postBody;
#JsonProperty("postTitle")
private String postTitle;
#JsonProperty("created")
private Object created;
#JsonProperty("tagList")
private String[] tagList = null;
#JsonIgnore
private Map<String, Object> additionalProperties = new HashMap<String, Object>();
#JsonProperty("userId")
public int getUserId() {
return userId;
}
#JsonProperty("userId")
public void setUserId(int userId) {
this.userId = userId;
}
#JsonProperty("postBody")
public String getPostBody() {
return postBody;
}
#JsonProperty("postBody")
public void setPostBody(String postBody) {
this.postBody = postBody;
}
#JsonProperty("postTitle")
public String getPostTitle() {
return postTitle;
}
#JsonProperty("postTitle")
public void setPostTitle(String postTitle) {
this.postTitle = postTitle;
}
#JsonProperty("created")
public Object getCreated() {
return created;
}
#JsonProperty("created")
public void setCreated(Object created) {
this.created = created;
}
#JsonProperty("tagList")
public String[] getTagList() {
return tagList;
}
#JsonProperty("tagList")
public void setTagList(String[] tagList) {
this.tagList = tagList;
}
#JsonAnyGetter
public Map<String, Object> getAdditionalProperties() {
return this.additionalProperties;
}
#JsonAnySetter
public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}
}
I am creating simple rest client in Java/Spring. My request has been consumed properly by remote service and I got the response String something:
{"access_token":"d1c9ae1b-bf21-4b87-89be-262f6","token_type":"bearer","expires_in":43199,"grant_type":"client_credentials"}
The code below is the Object where I want to bind values from Json Response
package Zadanie2.Zadanie2;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonProperty;
public class Token {
String access_token;
String token_type;
int expiresIn;
String grantType;
//////////////////////////////////////////////////////
public Token() {
/////////////////////////////////
}
/////////////////////////////////////////////////////
public void setAccessToken(String access_token) {
this.access_token=access_token;
}
public String getAccessToken() {
return access_token;
}
////////////////////////////////////////////////
public void setTokenType(String token_type) {
this.token_type=token_type;
}
public String getTokenType() {
return token_type;
}
//////////////////////////////////////////////////////
public void setExpiresIn(int expiresIn) {
this.expiresIn=expiresIn;
}
public int getExpiresIn() {
return expiresIn;
}
//////////////////////////////////////////////////////////
public void setGrantType(String grantType) {
this.grantType=grantType;
}
public String getGrantType() {
return grantType;
}
}
all the time I am getting "unrecognized field access_token" but when I add objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
then access_token will be null
jsonAnswer=template.postForObject(baseUriAuthorize, requestEntity, String.class);
System.out.println(jsonAnswer);
Token token=objectMapper.readValue(jsonAnswer, Token.class);
System.out.println(token.getAccessToken());
I tried with #JsonProperty annotations. I tried with changing field by for example "#JsonProperty(accessToken)" because I thought there is an issue with "_" sign in variable name. I added getters and setters. Maybe there is a problem with the version I use but I don't think so because I am using "com.fasterxml.jackson.core"
You tried with "#JsonProperty(accessToken)". But your json contains access_token. how it works?
Try with this class:
public class Token {
#JsonProperty("access_token")
String accessToken;
#JsonProperty("token_type")
String tokenType;
int expiresIn;
String grantType;
//getter setter
}
Your setters do not match with the JSON key.
To read it correctly, you should change your setters to:
setAccess_token()
setToken_type()
...
But honestly, this is so ugly.
Try following the Java bean name convention and customize the JSON key with #JsonProperty:
public class Token {
#JsonProperty("access_token")
String accessToken;
....
}
I've got a bit of a conundrum. I'm trying to deserialize a json message into a pojo using the builder pattern and I'm getting the following error:
Caused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "Information"
(class com.verification.client.models.response.Response$Builder), not marked as ignorable (3 known properties: "status", "products", "information"])
This is very confusing to me as I've clearly marked the field in the pojo with a JsonProperty annotation:
#JsonDeserialize(builder = Response.Builder.class)
#JsonInclude(JsonInclude.Include.NON_EMPTY)
public class Response {
#JsonProperty("Status")
private final Optional<Status> status;
#JsonProperty("Products")
private final Optional<List<ResponseProduct>> products;
#JsonProperty("Information") //Here's where the field is defined
private final Optional<List<ResponseInformation>> information;
private Response(final Builder b){
this.status = b.status;
this.products = b.products;
this.information = b.information;
}
public Optional<Status> getStatus() {
return status;
}
public Optional<List<ResponseProduct>> getProducts() {
return products;
}
public Optional<List<ResponseInformation>> getInformation() {
return information;
}
#JsonPOJOBuilder(buildMethodName = "build", withPrefix = "")
public static class Builder{
private Optional<Status> status;
private Optional<List<ResponseProduct>> products = Optional.empty();
private Optional<List<ResponseInformation>> information = Optional.empty();
public Builder(){}
public Builder status(final Status status){
this.status = Optional.of(status);
return this;
}
public Builder products(final List<ResponseProduct> products){
this.products = Optional.of(products);
return this;
}
public Builder information(final List<ResponseInformation> information){
this.information = Optional.of(information);
return this;
}
public Response build(){
return new Response(this);
}
}
}
I have a feeling it's something small, but at this point I am at a loss for why my code is behaving this way.
P.S.
Here's the json I'm deserializing
{
"Information": [{
"InformationType": "error-details",
"Code": "internal_application_error",
"Description": "Error: Internal",
"DetailDescription": []
}]
}
Solved this a while back, answering for posterity.
The issue I was having is that the build methods were not being correctly interpreted, but by defining #JsonSetter annotations on the methods of the static build class Jackson was able to correctly interpret the input and build the object.
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)