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/
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 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.
I am working on a Spring Boot application an am having issues where items are not being auto-wired as I expect. What is adding to this confusion is that I have another Spring Boot application that also happens to involve Vaadin. In this application, auto-wiring seems more "automated".
Here is what I mean. In the Vaadin app, a #Service object, is injected into a Vaadin "view" with little effort. Additionally, the service object itself is injected with a Repository object. I need to do almost nothing to make this all happen.
In my other non-Vaadin application, I set up the code to do similar things, but in this case, it does not work. The application fails to start and complains as below:
***************************
APPLICATION FAILED TO START
***************************
Description:
Parameter 0 of constructor in com.mycompany.app.backend.service.TaskMasterService required a bean of type 'com.mycompany.app.backend.repository.TaskMasterRepository' that could not be found.
Action:
Consider defining a bean of type 'com.mycompany.app.backend.repository.TaskMasterRepository' in your configuration.
I assume that I'm missing some configuration somewhere, or that the Vaadin application has "extra" functionality added that makes this work.
Here are snippets of the Vaadin application:
TasksView.java:
#Route("main")
public class TasksView extends VerticalLayout {
private final TaskService taskService;
private final TaskNoteService noteService;
public TasksView(TaskService taskService, TaskNoteService noteService) {
this.taskService = taskService;
this.noteService = noteService;
}
...
}
TaskService.java:
#Service
#Transactional
public class TaskService {
private TaskRepository taskRepo;
public TaskService(TaskRepository taskRepo) {
this.taskRepo = taskRepo;
}
...
}
TaskRepository.java:
public interface TaskRepository extends JpaRepository<Task, Long>, TaskRepositoryCustom {
...
}
I don't need to #Autowired anything or provide a #Configuration class or define a #Bean anywhere. It just works.
Here are some snippets from the non-Vaadin application:
IngesterRunner.java:
#Service
public class IngesterRunner {
private TaskMasterService tmService;
private TaskRelationshipService trService;
private VariantDetailService vdService;
public IngesterRunner(TaskMasterService tmService, TaskRelationshipService trService,
VariantDetailService vdService) {
this.tmService = tmService;
this.trService = trService;
this.vdService = vdService;
}
...
}
TaskMasterService.java:
#Service
#Transactional
public class TaskMasterService {
private final TaskMasterRepository repo;
public TaskMasterService(TaskMasterRepository repo) {
this.repo = repo;
}
...
}
TaskMasterRepository.java:
package com.mycompany.app.backend.repository;
public interface TaskMasterRepository extends JpaRepository<TaskMaster, Long> {
}
JPAConfiguration.java:
#Configuration
#EnableJpaRepositories(basePackages = "com.mycompany.app.backend.repository", transactionManagerRef = "jpaTransactionManager")
#EnableTransactionManagement
public class JPAConfiguration {
private static final String[] ENTITY_PACKAGES_TO_SCAN = {
"com.mycompany.app.backend.entity" };
...
}
I don't understand what is different about the first application that makes auto-wiring work so much more smoothly. Is it something I have in my pom.xml? Is it some sort of extra support provided by Vaadin?
If requested, I can try to include the POM files if that will help.
Update:
I have tried a number of suggestions, but none seem to have any effect. I added #Autowired annotations, but it makes no difference.
#Service
public class IngesterRunner {
private TaskMasterService tmService;
private TaskRelationshipService trService;
private VariantDetailService vdService;
public IngesterRunner(#Autowired TaskMasterService tmService,
#Autowired TaskRelationshipService trService, #Autowired VariantDetailService vdService) {
this.tmService = tmService;
this.trService = trService;
this.vdService = vdService;
}
...
}
#Service
#Transactional
public class TaskMasterService {
private final TaskMasterRepository repo;
public TaskMasterService(#Autowired TaskMasterRepository repo) {
this.repo = repo;
}
...
}
#Repository annotation in TaskMasterRepository.java, like
#Repository
public interface TaskMasterRepository extends JpaRepository<TaskMaster, Long> {
}
I have the following:
public abstract class ReportGenerationStrategy<T extends ReportParameter> {
public abstract void generate(T reportParameter) throws IOException;
}
The subclasses:
#Component
#AllArgsConstructor
public class DeferredRevenueReportGenerationStrategy extends ReportGenerationStrategy<DeferredRevenueReportParameter> {
}
#Component
#AllArgsConstructor
public class OffBalanceExposureReportGenerationStrategy extends ReportGenerationStrategy<OffBalanceExposureReportParameter> {
}
I am creating a map with the subclasses:
#Bean
public Map<ReportType, ReportGenerationStrategy<? extends ReportParameter>> generationStrategies(
#Qualifier("deferredRevenueReportGenerationStrategy") final ReportGenerationStrategy<? extends ReportParameter> deferredRevenue,
#Qualifier("offBalanceExposureReportGenerationStrategy") final ReportGenerationStrategy<? extends ReportParameter> offBalanceExposure
)
{
return ImmutableMap.of(
ReportType.DEFERRED_REVENUE, deferredRevenue,
ReportType.OFF_BALANCE_EXPOSURE, offBalanceExposure
);
}
And trying to inject the map as following:
#AllArgsConstructor
#Slf4j
public class ReportApplicationServices {
private final Map<ReportType, ReportGenerationStrategy<ReportParameter>> generationStrategies; //Empty map injected
}
But I receive an empty map on the field...
Why is this happening?
I believe you missed to use #Autowire annotation on the private final Map that you have declared.
Hope this helps and solves the issue.