I have the following entity in spring boot application:
#Entity
#Data
#AllArgsConstructor
#NoArgsConstructor
#Audited
#XmlRootElement
#XmlAccessorType(XmlAccessType.NONE)
#Table(name = "currency", catalog = "currency_db")
public class Currency implements java.io.Serializable {
#Autowired
Messages messages;
As for message, it just a container of spring MessageSource here it is:
#ApplicationScope
#Component
#Slf4j
public class Messages {
#Autowired
private MessageSource messageSource;
private MessageSourceAccessor accessor;
#PostConstruct
private void init() {
accessor = new MessageSourceAccessor(messageSource, Locale.ENGLISH);
log.info("Messages initialized");
}
public String get(String code) {
return accessor.getMessage(code);
}
}
I'm getting the following error when run mvn clean install. Any idea what I'm missing here?
org.hibernate.MappingException: Could not determine type for: com.company.currencyservice.Messages, at table: currency, for columns: [org.hibernate.mapping.Column(messages)]
It's looks like hibernate think it's a column. Thanks.
Entities are not Spring beans and therefor you cannot use dependency injection in entities.
If you want to access a Spring bean from within an entity you can use a helper class like this:
#Service
public class ApplicationContextProvider implements ApplicationContextAware {
private static ApplicationContext context;
public static <T> T bean(Class<T> beanType) {
return context.getBean(beanType);
}
public static Object bean(String name) {
return context.getBean(name);
}
#Override
public void setApplicationContext(#SuppressWarnings("NullableProblems") ApplicationContext ac) {
context = ac;
}
}
Then you can use ApplicationContextProvider.getBean(Messages.class) to get access to the Messages.
Related
I use spring boot 3
I created a object manually, FormGenerator, because everytime I use is in my advance search, some field need to be reset.
So I think the scope prototype is ok for that
#Repository
public class SchoolRepositoryCustomImpl extends SimpleJpaRepository<School, Long> implements SchoolRepositoryCustom {
#Override
public List<School> advanceSearch(SchoolSearch search) {
FormGenerator qg = new FormGenerator();
}
...
}
#Scope("prototype")
public class FormGenerator {
private int fieldCounter=0;
#Autowired
private EntityManager entityManager;
...
}
When I run application, entityManager is null?
It is null because you created the object manually by calling the constructor. You need to obtain it from the ApplicationContext. Something like this:
#Repository
public class SchoolRepositoryCustomImpl extends SimpleJpaRepository<School, Long> implements SchoolRepositoryCustom {
#Autowired
private ApplicationContext applicationContext;
#Override
public List<School> advanceSearch(SchoolSearch search) {
FormGenerator qg = applicationContext.getBean(FormGenerator.class);
}
...
}
I'm giving this error:
Parameter 0 of constructor in x.microservice.module.business.application.BusinessCreator required a bean of type 'x.microservice.module.business.infrastructure.HibernateJpaRepository' that could not be found.
The injection point has the following annotations:
- #org.springframework.beans.factory.annotation.Autowired(required=false)
Action:
Consider defining a bean of type 'x.microservice.module.business.infrastructure.HibernateJpaRepository' in your configuration.
The controller:
#Slf4j
#RestController
public final class BusinessPostController {
#Autowired
private BusinessCreator creator;
#PostMapping(value = "/business")
public ResponseEntity create(#RequestBody Request request){
BusinessCreatorDto businessCreatorDto = new BusinessCreatorDto(IdentifierEpoch.generate(),request.getName());
return ResponseEntity.ok(
creator.create(businessCreatorDto)
);
}
}
The Application Layer:
#AllArgsConstructor
#Service
public class BusinessCreator {
#Autowired
private HibernateJpaRepository repository;
public BusinessResponse create(BusinessCreatorDto dto){
Business business = new Business(dto.getId(), dto.getName());
repository.save(business);
return BusinessResponse.fromAggregate(business);
}
}
In the Infrastructure layer
#Repository
public abstract class HibernateJpaRepository implements JpaRepository<Business, Long> {
}
The boot Application:
#EnableJpaRepositories
#SpringBootApplication
public class MicroserviceApplication {
public static void main(String[] args) {
SpringApplication.run(MicroserviceApplication.class, args);
}
}
All dependencies are resolved and the others classes I believe that are irrellevant.
Any suggestions? Thank you very much
Probably, the error cause is HibernateJpaRepository - it has to be an interface that extends JpaRepository.
You could write your own Repository in a interface:
#Repository
public interface HibernateJpaRepository extends JpaRepository < Business, Long > {
}
Then your Class:
#AllArgsConstructor
#Service
public class BusinessCreator {
#Autowired
private HibernateJpaRepository repository;
public BusinessResponse create(BusinessCreatorDto dto){
Business business = new Business(dto.getId(), dto.getName());
repository.save(business);
return BusinessResponse.fromAggregate(business);
}
}
I have a strange problem reading configuration, none of solutions I've seen seem to work. Here is my code:
#SpringBootApplication
#EnableConfigurationProperties
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
Here is my properties class
#Component
#ConfigurationProperties(prefix = "my")
#Data
#ToString
#NoArgsConstructor
#AllArgsConstructor
public class MyProperties {
private String host;
private int port;
}
I then use MyProperties class in my class using #Autowired:
#Autowired
private MyProperties props;
However, I'm getting null for my props object.
Strangely, this is passing the tests just perfectly:
#SpringBootTest
class ApplicationTests {
#Autowired
private MyProperties props;
#Test
void test_configuration() {
Assertions.assertEquals(props.getHost(), "xx.xx.xx.xx");//pass!
Assertions.assertEquals(props.getPort(), xxxxxx);//pass!
}
}
It has totally refused to work, and so has #Value injection. What could I be missing?
EDIT
Here's complete code of how I'm using #Autowired on MyProperties (I've included #Value which is also not working)
#Slf4j
#Component //also tried #Configurable, #Service
public class MyService {
#Autowired
private MyProperties props;
#Value("localhost")
public String host;
public void post() {
log.info(host + props);// =null and null
}
}
EDIT2
However, I've noticed that on the controller, it works perfectly okay:
#Slf4j
#RestController
#Service
public class Main {
#Autowired
private MyProperties props;
#Value("localhost")
private String host;
#GetMapping("/post")
public void post() {
log.info(host + props);//=it's perfect!
new MyService().post();// calling MyService - where #Autowired or #Value is failing
}
}
The reason this isn't working is because the MyService you're using isn't a Spring bean, but an instance you created by yourself (using new MyService()).
To make this work, you should autowire MyService, in stead of creating your own instance:
#Slf4j
#RestController
public class Main {
#Autowired // Autowire MyService
private MyService myService;
#GetMapping("/post")
public void post() {
myService.post(); // Use the myService field
}
}
For more information, look at this Q&A: Why is my Spring #Autowired field null.
UPDATE:
new MyService() is not a "spring bean", thus can't be auto-wired with anything!;)
1. Lombok
Some people use Project Lombok to add getters and setters automatically. Make sure that Lombok does not generate any particular constructor for such a type, as it is used automatically by the container to instantiate the object.
With "such a type" ConfigurationProperties is referred in Externalized Configuration (one of my favorite chapters;) More Exact: 2.8.1. JavaBean properties binding, at the bottom of second "Note!" ;)
So this could be a reason (for strange behavior).
I am having following code below.
#Builder(toBuilder = true)
#AllArgsConstructor(access = AccessLevel.PRIVATE)
#NoArgsConstructor(access = AccessLevel.PRIVATE)
#ToString
#EqualsAndHashCode
#Configurable
public class Employee {
#Autowired
#Qualifier("findEmpByDepartment")
private Function<Long, Long> empByDepartment;
private void save() {
this.empByDepartment.getList();
}
}
and FindEmpByDepartment class below.
#Component("findEmpByDepartment")
public class FindEmpByDepartment implements Function<Long, Long> {
public void getList() {
}
....
}
My problem is I am always getting null when invoke
this.empByDepartment.getList();
line. Here this.empByDepartment is coming as null. Any idea why it is like this?
Thanks
May be you would have missed annotating any class in the flow hierarchy .
#Service, #Repository and #Controller are all specializations of #Component, so any class you want to auto-wire needs to be annotated with one of them.
IoC is like the cool kid on the block and if you are using Spring then you need to be using it all the time .
So make sure you do not have any object created with new operator in the entire flow .
#Controller
public class Controller {
#GetMapping("/example")
public String example() {
MyService my = new MyService();
my.doStuff();
}
}
#Service
public class MyService() {
#Autowired
MyRepository repo;
public void doStuff() {
repo.findByName( "steve" );
}
}
#Repository
public interface MyRepository extends CrudRepository<My, Long> {
List<My> findByName( String name );
}
This will throw a NullPointerException in the service class when it tries to access the MyRepository auto-wired Repository, not because there is anything wrong with the wiring of the Repository but because you instantiated MyService() manually with MyService my = new MyService().
For more details , you can check
https://www.moreofless.co.uk/spring-mvc-java-autowired-component-null-repository-service/
I have the following scenario:
class Super{
private List<String> someStringsThatWillBeDifferentForEveryInstancePerDerivedType;
}
#Component
class Derived1 extends Super{
#Autowired
private String name;
}
#Component
class Derived2 extends Super{
#Autowired
private Long configId;
}
I have a different List defined as Spring bean in xml for each derived class…call them listForDerived1 and listForDerived2. How can I wire these lists into my derived classes? I attempted constructor injection but I can't seem to find any luck injecting both the collection and the other deps.
You can use constructor injection with #Qualifier.
class Super {
private List<String> someStrings;
public Super(private List<String> someStrings) {
this.someStrings = someStrings;
}
}
#Component
class Derived1 extends Super {
#Autowired
public Derived1(#Qualifier("listForDerived1") List<String> listForDerived1, OtherBean bean) {
super(listForDerived1);
}
}
#Component
class Derived2 extends Super {
#Autowired
public Derived1(#Qualifier("listForDerived2") List<String> listForDerived1, OtherBean bean) {
super(listForDerived2);
}
}
Also see official Spring doc: http://docs.spring.io/spring/docs/current/spring-framework-reference/htmlsingle/#beans-autowired-annotation-qualifiers