I've got a Spring REST web application. I've got a method which returns a response entity.
#RequestMapping(value = "/shoes", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<?> getShoes() {
Collection<Shoes> shoes = shoesService.findAll();
ResponseEntity responseEntity = new ResponseEntity<>(shoes, HttpStatus.OK);
return responseEntity;
}
When I set a breakpoint on the last line, I can see that the responseEntity contains a list of the following objects:
Shoes{id=1, localization=Localization{id=1, city='Denver'}, category=Category{id=1, name='wellingtons', group='male'}, size=9}
But when I send the request in client app, I get a JSON, which contains only id and size:
{
"id": 1,
"size": 9
}
I wonder why I don't receive localization and category.
Here is the Shoes class:
#Table(name = "shoes")
public class Shoes{
#Column(name = "id")
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#JsonBackReference
#ManyToOne
private Localization localization;
#JsonBackReference
#ManyToOne
private Category category;
#Column(name = "size")
private int size;
...
}
If you have bi-directional associations, you have to declare which object has the role of parent (annotated with JsonManagedReference) and which has the role of child (annotated with JsonBackReference) to break cycles.
You annotated both properties (localization, category) to not be serialized, see JsonBackReference:
Annotation used to indicate that associated property is part of two-way linkage between fields; and that its role is "child" (or "back") link. Value type of the property must be a bean: it can not be a Collection, Map, Array or enumeration. Linkage is handled such that the property annotated with this annotation is not serialized; and during deserialization, its value is set to instance that has the "managed" (forward) link.
Related
I am using the following class as an entity, and a controller class to write data on it:
#Entity
#Table(name = "TableA")
public class TableA {
#JsonProperty(access = JsonProperty.Access.READ_ONLY)
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(nullable = false, name="Id")
private BigInteger id;
#Column(nullable = false, name="Name")
private String name;
//Setters Getters
}
#RestController
public class TableAController {
#Autowired
TableARepository tableARepository;
#Transactional(rollbackFor = Exception.class)
#PostMapping(value="/CreateTableA")
public void createTableA(#RequestBody TableA newTableA){
TableA tableA = new TableA();
tableA = newTableA;
tableARepository.save(tableA);
}
}
The Id column value will be generated by the DB, so I used the #JsonProperty. But, when I test the REST API using the following as a request:
{
"name" : "Leo Messi"
}
I am getting the aforementioned error message. I have also tried the #JsonIgnore property with the same result. Is there a way to except the id property from the deserialization process? Or should I use another class dedicated the API Request? I am not comfortable with creating different models for every new API.
I am not sure if I should focus on resolving the error, or if I should design the classes using a Design Pattern that never produces it.
So I encountered this issue with updating an entity in DB. while Passing a whole entity and updating only specific fields it treats untouched fields as null, as a result I get an exception since those fields are #Not-Null,
I have tried looking for similar problems but could not fix my problem.
Company ENTITY:
#Entity
#Table (name = "companies")
#Data
#ToString(exclude = "perfumes")
#AllArgsConstructor
#NoArgsConstructor
#Builder
public class Company {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#NotNull
private String name;
#NotNull
#Email(message = "Wrong input. please enter a VALID email address")
private String email;
#NotNull
#Size(min = 4, max = 14, message = "Password range must be between 4 - 14 digits")
private String password;
#NotNull
#Enumerated(EnumType.STRING)
private Country country;
#Singular
#OneToMany(mappedBy = "company", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
private List<Perfume> perfumes = new ArrayList<>();
}
Most fields are #NotNull for creation, however, I need to update the entity, sometimes only specific fields.
Service:
#Override
public String updateCompany(int id, Company company) throws DoesNotExistException {
if(!companyRepository.existsById(id))
{
throw new DoesNotExistException(id);
}
companyRepository.saveAndFlush(company);
return company.getName() + " has been UPDATED";
}
as you can see an ENTITY has been passed which causes rest of attributes to be automatically null if not modified.
Controller:
#PutMapping("/updateCompany/{id}")
#ResponseStatus(HttpStatus.ACCEPTED)
public String updateCompany(#PathVariable int id, #RequestBody Company company) throws DoesNotExistException {
return admin.updateCompany(id,company);
}
EXCEPTION:
Validation failed for classes [com.golden.scent.beans.Company] during update time for groups [javax.validation.groups.Default, ]
List of constraint violations:[
ConstraintViolationImpl{interpolatedMessage='must not be null', propertyPath=password, rootBeanClass=class com.golden.scent.beans.Company, messageTemplate='{javax.validation.constraints.NotNull.message}'}
]
Thanks.
The controller is binding the values you pass in to a new Company entity. The new entity is not attached to the persistence context, it does not have the state of the pre-existing entity. When you save it JPA thinks you want to null out all the fields you don't have values for.
Instead, you could have the controller bind its arguments to a DTO. Then in the service you look up the existing Customer, using findById, and copy the fields you want updated from the DTO to the entity. Then call saveAndFlush passing in the updated entity.
It looks like there's an improvement over the DTO, you can use aJsonPatch to hold the updates passed in, see https://www.baeldung.com/spring-rest-json-patch. The patch method seems like a better match for what you're doing anyway.
On the server the important thing is to look up the existing entity so that you have an entity that is attached to the persistence context and has all its fields current.
I need to get two lists of two different types objects as parameters from a rest controller and it's sending me a
"error": "Internal Server Error",
"message": "Failed to convert value of type 'java.lang.String' to required type 'java.util.List';
nested exception is java.lang.IllegalStateException: Cannot convert value of type 'java.lang.String' to required type
'com.nord.execom.domain.Category': no matching editors or conversion strategy found"
Part of my controller:
#RequestMapping(
value = "/projects",
params = {"category", "location"},
method = GET)
#ResponseBody
public ResponseEntity<List<Project>> getProjects(#RequestParam("category") List<Category> category,
#RequestParam("location") List<Location> location) {
List<Project> project = projectService
.getProjects(category, location);
return ResponseEntity.ok().body(project);
}
My category object(location object is the same type):
#Entity
#Table(name = "category")
public class Category {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int Id;
#NotBlank
#Column(unique = true)
#Size(min = 1, max = 50)
private String name;
#OneToMany(mappedBy = "category")
private List<Project> project;
So i was wondering is there a way to let the controller know that i want to take the parameters as a list of objects and not Strings?
Define a model class
Define an arraylist in it.
Use #RequestBody annotation like below: -
ModelClass{
List<String> list;
//Getters and setter for the attribute
}
public ResponseEntity> getProjects(#ResponseBody ModelClass model) {
}
I'm seeing some videos about API Rest with Spring Boot and so far I've done some basics and when I tried to increase the complexity I'm getting caught.
My idea is in the Post / class, create a new class with students getting the following json:
{
"nome": "Primeira Serie - A".
"alunos": [
"João",
"José",
"Maria"
]
}
And return:
{
"id_classe": 101
}
It happens that it saves the class, but it does not save the students and I have no idea how to show only the id of the class.
I have created the following classes in Java:
Model
Classe.java
package com.example.classe.model;
//Import's suppressed
#Entity
#Table(name = "classe")
public class Classe {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
private String nome;
#OneToMany(mappedBy = "classe")
private Set<Aluno> alunos = new HashSet<Aluno>();
//Get's e Set's suppressed
}
Aluno.java
package com.example.classe.model;
//Import's suppressed
#Entity
#Table(name = "aluno")
public class Aluno {
private static int tempID = 0;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
private String nome;
#ManyToOne
#JoinColumn(name = "id_classe")
#JsonBackReference
private Classe classe;
public Aluno(String nome) {
tempID++;
this.id = tempID;
this.nome = nome;
}
public Aluno() {
}
//Get's e Set's suppressed
}
Repository
ClasseRepository.java
package com.example.classe.repository;
//Import's suppressed
#Repository
public interface ClasseRepository extends JpaRepository<Classe, Integer> {
public List<Classe> findAll();
}
Controller
ClasseController.java
package com.example.classe.controller;
//Import's suppressed
#RestController
#RequestMapping("/classe")
public class ClasseController {
#Autowired
private ClasseRepository classeRepo;
#RequestMapping(method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
public ResponseEntity<Collection<Classe>> getClasse() {
return new ResponseEntity<>(classeRepo.findAll(), HttpStatus.OK);
}
#RequestMapping(method = RequestMethod.POST)
public ResponseEntity<?> salvarClasse(#RequestBody Classe classe) {
return new ResponseEntity<>(classeRepo.saveAndFlush(classe), HttpStatus.CREATED);
}
}
Am I doing everything wrong or did I not understand the concept? But I wanted to understand how to do it that way.
Thanks in advance.
Cesar Sturion
What you want to achieve is totally doable, but requires several changes.
I split my answer into 2 parts:
Save the students
There are several problems with saving:
On POST your incoming json deserialized into objects in which Classe has a reference to Anuli, but Anuli doesn't have a reference toClasse. To check it you can add a break point at the line: return new ResponseEntity<>(... , run in debug mode and check fields of Anuli in Classe. To fix it you can add #JsonManagedReference on aluni field in Classe. Related question
Hibernate can't save referenced objects by default. You have to save them one by one after saving your Classe object or just turn on Cascade persisting. Related question
So, to fix 1 and 2 Classe should have:
#OneToMany(mappedBy = "classe", cascade = CascadeType.PERSIST)
#JsonManagedReference
private Set<Aluno> alunos = new HashSet<Aluno>();
You have to remove custom id generation in Alumi (I am talking about static int tempID). Annotation #GeneratedValue will perfectly generate id for you as soon as you persist an object. This custom generation breaks Hibernate support. I even not talking about that it also breaks the app after restart, not threadsafe etc.
Return id only
On POST returned json represent what was returned in classeRepo.saveAndFlush(classe) so it's an object of Classe.
If you want to return exactly this:
{
"id_classe": 101
}
Then create new class like this:
public class ClasseIdVO {
#JsonProperty("id_casse")
private Integer id;
// Constructors, getter, setter
VO - means View Object, so this object only for representation, not for persisting, etc.
You can use field name id_casse, but it's against Java code convention, so better add #JsonProperty.
Also change your saving code to new ClasseIdVO(classeRepo.saveAndFlush(classe).getId())
Or you can just return id as a number: classeRepo.saveAndFlush(classe).getId()
I have 2 domain models and one Spring REST Controller like below:
#Entity
public class Customer{
#Id
private Long id;
#OneToOne(fetch = FetchType.EAGER)
#JoinColumn(name="COUNTRY_ID", nullable=false)
private Country country;
// other stuff with getters/setters
}
#Entity
public class Country{
#Id
#Column(name="COUNTRY_ID")
private Integer id;
// other stuff with getters/setters
}
Spring REST Controller:
#Controller
#RequestMapping("/shop/services/customers")
public class CustomerRESTController {
/**
* Create new customer
*/
#RequestMapping( method=RequestMethod.POST)
#ResponseStatus(HttpStatus.CREATED)
#ResponseBody
public com.salesmanager.web.entity.customer.Customer createCustomer(#Valid #RequestBody Customer customer, Model model, HttpServletRequest request, HttpServletResponse response) throws Exception {
customerService.saveOrUpdate(customer);
return customer;
}
// other stuff
}
I am trying to call above REST service with below JSON as body:
{
"firstname": "Tapas",
"lastname": "Jena",
"city": "Hyderabad",
"country": "1"
}
Where country code 1 is already there in Country table. The problem is when I am calling this service getting below error:
org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.TransientPropertyValueException: Not-null property references a transient value - transient instance must be saved before current operation: com.test.model.Customer.country -> com.test.model.Country; nested exception is java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: Not-null property references a transient value - transient instance must be saved before current operation: com.test.model.Customer.country -> com.test.model.Country
Any help will be appreciated!
Try putting CascadeType.ALL
#OneToOne(fetch = FetchType.EAGER,cascade=CascadeType.ALL)
#JoinColumn(name="COUNTRY_ID", nullable=false)
private Country country;
I had a similar problem. Two entities: Document and Status.
Document had a relationship OneToMany with Status, that represented the history of Status the Document had.
So, there was a #NotNull #ManyToOne reference of Document inside Status.
Also, I needed to know the actual Status of Document. So, I needed another relationship, this time #OneToOne, also #NotNull, inside Document.
The problem was: how can I persist both entities the first time if both had a #NotNull reference to the other?
The solution was: remove #NotNull reference from actualStatus reference. This way, it was able to persist both entities.
Just to add an additional scenario that led me to this exact same error:
Make sure that any backward references that may exist are not null.
Specifically in my case, I was using Mapstruct to update some fields of the entity, e.g.
MyClass newInstance = //...
MyClass dbInstance = repository.findByField(someField);
MyClassMapper.MAPPER.update(dbInstance, newInstance);
repository.save(dbInstance);
And my poor implementation of MyClassMapper led the backward references of dbInstance fields to be set to null when they should be pointing back to dbInstance.
I got same error and this is how I solved it:
1st Entity:
#Entity
public class Person implements Serializable{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int personId;
private String name;
private String email;
private long phoneNumber;
private String password;
private String userType;
#OneToOne(fetch = FetchType.LAZY, mappedBy = "personCustomer", cascade
= CascadeType.ALL)
private Customer customer;
2nd Entity:
#Entity
public class Customer implements Serializable{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int customerId;
#OneToOne(fetch = FetchType.LAZY, optional = false, cascade =
CascadeType.ALL)
#JoinColumn(name = "person_customer")
#JsonIgnore
private Person personCustomer;
My Controller:
#PostMapping("/customer/registration")
public PersonCustomer addCustomer(#RequestBody Person person)
{
Customer customer = new Customer(person);
person.setCustomer(customer);
Customer cust = customerRepo.save(customer);
logger.info("{}", cust);
Optional<Person> person_Cust =
personRepo.findById(cust.getPersonCustomer().getPersonId());
Person personNew = person_Cust.get();
PersonCustomer personCust = new PersonCustomer();
if(cust.equals(null))
{
personCust.setStatus("FAIL");
personCust.setMessage("Registration failed");
personCust.setTimestamp(personCust.timeStamp());
}
personCust.setStatus("OK");
personCust.setMessage("Registration OK");
personCust.setTimestamp(personCust.timeStamp());
personCust.setPerson(personNew);
return personCust;
}
The problem got solved when I added "person.setCustomer(customer);".
As both POJO classes has each others reference, so we have to "set" each others reference before using the JPA repository method(customerRepo.save(customer));
I had the exact same problem. The solution seems to be to send the JSON like this:
{
"firstname": "Tapas",
"lastname": "Jena",
"city": "Hyderabad",
"country": {"id":"1"}
}
I guess #RequestBody tries to map an entity not a single field since the Customer instance is referencing a Country instance.
(I have similarly two entities, joined. In the DB, records for the referenced entity (Country in your case) were already created but the entity creation (Customer in your case) with a json, provided the same error message. For me CascadeType.ALL not helped but the above written change in the JSON solved the problem. For further config of course CascadeType can be considered.)
you should change :
#OneToOne(fetch = FetchType.EAGER)
#JoinColumn(name="COUNTRY_ID", nullable=false)
private Country country;
to :
#OneToOne(fetch = FetchType.EAGER)
#JoinColumn(name="COUNTRY_ID")
private Country country;
just delete nullable setting.