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Springboot adding a "_class" field in POST Request

I am new to SpringBoot and I am trying to connect my SpringBoot App to MongoDB. The GET Request is working completely fine but the POST Request is adding a "_class" field in the data which I don't want. I did some searching and found that I have to add a #Configuration class to solve this issue but when I added the #Configuration class, I am getting the following error :
Field mongoDbFactory in com.example.demo.configuration.MongoConfig required a bean of type 'org.springframework.data.mongodb.MongoDbFactory' that could not be found.
My Confuguration class code is as follows :-
MongoConfig.java :-
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.MongoDbFactory;
import org.springframework.data.mongodb.core.convert.DbRefResolver;
import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
import org.springframework.data.mongodb.core.convert.DefaultMongoTypeMapper;
import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
#Configuration
public class MongoConfig {
#Autowired
private MongoDbFactory mongoDbFactory;
#Autowired
private MongoMappingContext mongoMappingContext;
#Bean
public MappingMongoConverter mappingMongoConverter() {
DbRefResolver dbRefResolver = new DefaultDbRefResolver(mongoDbFactory);
MappingMongoConverter converter = new MappingMongoConverter(dbRefResolver,
mongoMappingContext);
converter.setTypeMapper(new DefaultMongoTypeMapper(null));
return converter;
}
}
Controller.java :-
import com.example.demo.model.Todo;
import com.example.demo.services.TodoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
#RestController
public class Controller {
#Autowired
private TodoService todoService;
#GetMapping("/")
public List<Todo> getTodos() {
return todoService.getTodos();
}
#PostMapping("/")
public Todo addTodo(#RequestBody Todo todo) {
return todoService.addTodo(todo);
}
}
TodoService.java :-
import com.example.demo.model.Todo;
import java.util.List;
public interface TodoService {
public List<Todo> getTodos();
public Todo addTodo(Todo todo);
}
TodoServiceImplementation.java :-
import com.example.demo.model.Todo;
import com.example.demo.repository.TodoRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
#Service
public class TodoServiceImplementation implements TodoService{
#Autowired
private TodoRepository todoRepository;
#Override
public List<Todo> getTodos() {
return todoRepository.findAll();
}
#Override
public Todo addTodo(Todo todo) {
return todoRepository.save(todo);
}
}
It is asking me to do the following action :-
Consider defining a bean of type 'org.springframework.data.mongodb.MongoDbFactory' in your configuration.

Springboot and IDEA error: Could not autowire. No beans of 'EntityLinks' type found

I am following Spring in action 5th edition to learn Springboot. When I am in chapter 6, I find that my IDEA IDE seems to have a bug for bean org.springframework.hateoas.server.EntityLinks.
package tech.enigma.web.api;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Sort;
import org.springframework.hateoas.server.EntityLinks;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import tech.enigma.Taco;
import tech.enigma.data.TacoRepository;
#RestController
#RequestMapping(path = "/design", produces = "application/json")
#CrossOrigin(origins = "*")
public class DesignTacoController
{
private TacoRepository tacoRepo;
private EntityLinks entityLinks;
public DesignTacoController(TacoRepository tacoRepo, EntityLinks entitylinks)
{
this.tacoRepo = tacoRepo;
this.entityLinks = entitylinks;
}
#GetMapping("/recent")
public Iterable<Taco> recentTacos()
{
PageRequest page = PageRequest.of(
0, 12, Sort.by("createAt").descending());
return tacoRepo.findAll(page).getContent();
}
}
At public DesignTacoController(TacoRepository tacoRepo, EntityLinks entitylinks) Constructor, IDEA gives an error "Could not autowire. No beans of 'EntityLinks' type found." I can compile and run my program although I am not sure it works properly.
Other beans all works ok.
Is this just a bug of IDEA or I got something wrong?

This is a known issue. IntelliJ will not always pickup all available beans due to incorrect scanning of autoconfigured resources.
What counts is the Spring runtime. If it doesn't result in an error, you are good to go.

#Autowired annotation is missing. Either do constructor injection or setter injection then it will work.
package tech.enigma.web.api;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Sort;
import org.springframework.hateoas.server.EntityLinks;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import tech.enigma.Taco;
import tech.enigma.data.TacoRepository;
#RestController
#RequestMapping(path = "/design", produces = "application/json")
#CrossOrigin(origins = "*")
public class DesignTacoController
{
#Autowired
private TacoRepository tacoRepo;
#Autowired
private EntityLinks entityLinks;
#GetMapping("/recent")
public Iterable<Taco> recentTacos()
{
PageRequest page = PageRequest.of(
0, 12, Sort.by("createAt").descending());
return tacoRepo.findAll(page).getContent();
}
}

Spring Reactive - problem with fromObject() method in BodyInserters class

I tried following the documentation tutorial, but I have some issues with depracated method. Specially in this line
.then(item-> ServerResponse.ok().contentType(APPLICATION_JSON).body(fromObject(item)))
The error is : Target type of a lambda conversion must be an interface.
Below is whole code. Thanks for your help
package com.learnreactivespring.learnreactivespring.handler;
import com.learnreactivespring.learnreactivespring.document.Item;
import com.learnreactivespring.learnreactivespring.repository.ItemReactiveRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.reactive.function.server.ServerRequest;
import org.springframework.web.reactive.function.server.ServerResponse;
import reactor.core.publisher.Mono;
import static org.springframework.http.MediaType.APPLICATION_JSON;
import static org.springframework.web.reactive.function.BodyInserters.fromObject;
#Component
public class ItemsHandler {
#Autowired
ItemReactiveRepository itemReactiveRepository;
public Mono<ServerResponse> getAllItems(ServerRequest serverRequest) {
return ServerResponse.ok()
.contentType(APPLICATION_JSON)
.body(itemReactiveRepository.findAll(), Item.class);
}
public Mono<ServerResponse> getOneItem(ServerRequest request) {
String itemId = request.pathVariable("id");
Mono<ServerResponse> notFound = ServerResponse.notFound().build();
Mono<Item> itemMono = this.itemReactiveRepository.findById(itemId);
return itemMono
.then(item -> ServerResponse.ok().contentType(APPLICATION_JSON).body(fromObject(item)))
.otherwiseIfEmpty(notFound);
}
}

Spring Boot Inject CrudRepository into Service

I am having difficulty injecting a CrudRepository into a service annotated with the #Service annotation. I have two packages one "core" package containing #Service definitions and reusable controller definitions.
My main application in the x.y.application package is as follows:
package x.y.application;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.context.web.SpringBootServletInitializer;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ImportResource;
#SpringBootApplication
#EnableAutoConfiguration
#ComponentScan({ "x.y.application", "x.y.core" })
public class Application {
public static void main( String[] args ) {
SpringApplication.run( Application.class, args );
}
}
Then an example Controller.
package x.y.application.controller;
import javax.inject.Inject;
import java.util.ArrayList;
import java.util.List;
import java.util.Iterator;
import x.y.application.model.User;
import x.y.core.controller.Controller;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.data.repository.CrudRepository;
#RestController
#RequestMapping("/test")
public class HelloController extends Controller<User> {
}
Then my re-usable controller class
package x.y.core.controller;
import javax.inject.Inject;
import java.util.ArrayList;
import java.util.List;
import java.util.Iterator;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.http.HttpStatus;
import org.springframework.data.repository.CrudRepository;
import org.springframework.dao.DataIntegrityViolationException;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.beans.factory.annotation.Autowired;
import x.y.core.service.Service;
public class Controller<T> {
#Inject
Service<T> service;
#RequestMapping(value = "/index.json", method = RequestMethod.POST, produces = MediaType.APPLICATION_JSON_VALUE)
public T create( #RequestBody T item ) throws Exception {
return service.create( item );
}
#RequestMapping(value = "/{id}.json", method = RequestMethod.PUT, produces = MediaType.APPLICATION_JSON_VALUE)
#ResponseStatus(value = HttpStatus.NO_CONTENT)
public T update( #PathVariable Long id, #RequestBody T item ) throws Exception {
return service.update( item );
}
#RequestMapping(value = "/{id}.json", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
public T read( #PathVariable Long id ) throws Exception {
return service.findOne( id );
}
#RequestMapping(value = "/index.json", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
public List<T> readAll() throws Exception {
return service.findAll();
}
#RequestMapping(value = "/{id}.json", method = RequestMethod.DELETE, produces = MediaType.APPLICATION_JSON_VALUE)
#ResponseStatus(value = HttpStatus.NO_CONTENT)
public void delete( #PathVariable Long id ) throws Exception {
service.delete( id );
}
}
Then my service interface
package x.y.core.service;
import javax.inject.Inject;
import java.util.ArrayList;
import java.util.List;
import java.util.Iterator;
import java.lang.reflect.*;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.http.HttpStatus;
import org.springframework.data.repository.CrudRepository;
import org.springframework.dao.DataIntegrityViolationException;
public interface Service<T> {
/**
* create.
* Creates a new entity in the database.
*/
public T create( T item );
/**
* update.
* Updates an existing entity in the database.
*/
public T update( T item );
public T findOne( Long id );
public List<T> findAll();
public void delete( Long id );
}
And finally the problematic implementation of service.
package x.y.core.service;
import javax.inject.Inject;
import java.util.ArrayList;
import java.util.List;
import java.util.Iterator;
import java.lang.reflect.*;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.http.HttpStatus;
import org.springframework.data.repository.CrudRepository;
import org.springframework.dao.DataIntegrityViolationException;
import org.springframework.beans.factory.annotation.Autowired;
#org.springframework.stereotype.Service
public class RepositoryService<T> implements Service<T> {
#Inject //Throws exception
CrudRepository<T,Long> repository;
/**
* create.
* Creates a new entity in the database.
*/
public T create( T item ) throws DataIntegrityViolationException {
/*try {
Field field = item.getClass().getDeclaredField( "id" );
field.setAccessible( true );
if( repository.exists( field.getLong( item ) ) ) {
throw new DataIntegrityViolationException( "Entity object already exists." );
}
} catch ( Exception exception ) {
throw new DataIntegrityViolationException( "Entity class does not contain Id attribute." );
}
return repository.save( item );*/ return item;
}
/**
* update.
* Updates an existing entity in the database.
*/
public T update( T item ) throws DataIntegrityViolationException {
/*try {
Field field = item.getClass().getDeclaredField( "id" );
field.setAccessible( true );
if( !repository.exists( field.getLong( item ) ) ) {
throw new DataIntegrityViolationException( "Entity object does not exists." );
}
} catch ( Exception exception ) {
throw new DataIntegrityViolationException( "Entity class does not contain Id attribute." );
}
return repository.save( item );*/ return item;
}
public T findOne( Long id ) {
/*if( !repository.exists( id ) ) {
throw new DataIntegrityViolationException( "Item with id does not exists." );
}
return repository.findOne( id );*/ return null;
}
public List<T> findAll() {
final List<T> resultList = new ArrayList<>();
/*/ final Iterator<T> all = repository.findAll().iterator();
while( all.hasNext() ) {
resultList.add( all.next() );
}*/
return resultList;
}
public void delete( Long id ) {
/*if( !repository.exists( id ) ) {
throw new DataIntegrityViolationException( "Item with id does not exists." );
}
repository.delete( id );*/
}
}
The exception
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.data.repository.CrudRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {#javax.inject.Inject()}
It seems that any spring registered Component, Service, Resource cannot inject CrudRepository?
However if i do not annotate the CrudRepository in the x.y.application package it compiles and the CrudRepository is injected?

For dependency injection to work application context has to know a recipe for creating an instance of a specific class. Classes whose instance creation recipes are known are referred to as "beans". You can define beans either via XML configuration file (old school) or annotations (new school).
The error message you are receiving states that the application context does not have CrudRepository bean, i.e. it does not know how to create an instance of a class that implements this interface.
To create a bean definition in a new way you may annotate a class or a specific method which return instance of a specific class with #Bean or any other meta-annotation that includes it (#Service, #Controller, etc.).
If you intend to use Spring Data suite of projects to automate repository implementation generation, you need to annotate an interface which extends one of the core Spring Data interfaces (Repository, CrudRepository, PagingAndSortingRepository) with #Repository annotation like so
#Repository
public interface MyRepository extends CrudRepository<Entity, Long> {
}
This provides a bean definition for the application context and makes it aware that you want the repository implementation to be generated for you.
Then you can inject MyRepository to the service class.
The only doubt I have is about the generic type to be used in repository type definition. I would expect the repository implementation (the one you want to be generated for you) to be entity-specific rather than abstract.

This is probably because CrudRepository is not part of your package scan. And hence spring is unable to inject a proxy implementation for it.

How to add HTTP lifecycle middleware handler to spring?

I have a CustomerController.java:
package com.satisfeet.http;
import java.util.ArrayList;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import com.satisfeet.core.model.Address;
import com.satisfeet.core.model.Customer;
import com.satisfeet.core.service.CustomerService;
#RestController
#RequestMapping("/customers")
public class CustomerController {
#Autowired
private CustomerService service;
#RequestMapping(method = RequestMethod.GET)
public Iterable<Customer> index() {
return this.service.list();
}
#RequestMapping(method = RequestMethod.POST)
public Customer create(#RequestBody Customer customer) {
this.service.create(customer);
return customer;
}
#RequestMapping(method = RequestMethod.GET, value = "/{id}")
public Customer show(#PathVariable Integer id) {
return this.service.show(id);
}
#RequestMapping(method = RequestMethod.PUT, value = "/{id}")
public void update(#PathVariable Integer id, #RequestBody Customer customer) {
this.service.update(id, customer);
}
#RequestMapping(method = RequestMethod.DELETE, value = "/{id}")
public void destroy(#PathVariable Integer id) {
this.service.delete(id);
}
}
and a ExceptionController.java:
package com.satisfeet.http;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseStatus;
import com.satisfeet.core.exception.NotFoundException;
#ControllerAdvice
public class ExceptionController {
#ExceptionHandler(NotFoundException.class)
public ResponseEntity notFoundError() {
return new ResponseEntity(HttpStatus.NOT_FOUND);
}
}
I would now like to add some sort of HTTP request-response middleware which is executed before the response is written and write the HTTP status code in json:
HTTP/1.1 404 OK
Connection: close
Content-Type: application/json
{"error":"not found"}
I know how to convert a HttpStatus to a String but I do not know where I could do this globally with #ControllerAdvice.
So how do I register a global handler which has access to a response object?

i think what you are looking for is spring Interceptor .
please check this tutorial which is describing how to use interceptors .
and check spring documentation Intercepting requests with a HandlerInterceptor .
finally check this answer here
Hope that helps .

To whom ever this may concern regarding the answer, the class HandlerInterceptorAdapter is now deprecated. You can implement the HandlerInterceptor which comes in the form of an interface instead. You can then implement preHandle, postHandle, or afterCompletion methods. See this question.