I have the following Entity
#Entity
#Table(name="user_app")
public class User implements Serializable {
private static final long serialVersionUID = 4992188185008895307L;
private String id;
...
public User(){
}
#Id
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
The Id is of type String
I am working with Spring Data JPA, and I have the following:
public interface UserRepository extends JpaRepository<User, String> {
}
I am working with AOP and I have the following:
#Before("execution(* *..UserRepository.findOne(..))")
public void beforeRepositoryLogging(JoinPoint jointPoint){
logger.info(">>Before {} called", jointPoint.getSignature().getName());
}
It works fine.
But if I change from:
#Before("execution(* *..UserRepository.findOne(..))")
to
#Before("execution(* *..UserRepository.findOne(String))")
It does not works anymore. Why?
Until here according with the API:
JpaRepository
Interface JpaRepository<T,ID extends Serializable>
Where ID according with the API
Repository
ID - the type of the id of the entity the repository manages
Remember:
My repository has JpaRepository<User, String>, the ID therefore is String
and the findOne method signature is T findOne(ID id). How conlusion, the type of my ID is String.
Therefore what is missing?
Thanks in advance.
Related
so I have following hierarchy of entities:
#MappedSuperClass
public abstract class BaseEntity {
private Long id;
private Date createAt;
private Date updateAt;
}
#Entity
#Inheritance(strategy = InheritanceType.SINGLE_TABLE)
public abstract class Post extends BaseEntity {
private String creatorId;
private String title;
private String content;
}
#Entity
public class Article extends Post {
private String category; // article has category
}
#Entity
public class Journal extends Post {
private Date expiration; // journal has expiration
}
now when I use Spring Jpa Specification to query for articles with certain category, it won't work:
// define specification
public class ArticleSpecifications {
public static Specification<Article> withCategory(String category) {
(root, query, criteriaBuilder) ->
criteriaBuilder.equal(root.get("category"), category)
}
}
// repository
public interface PostRepository<T extends Post> extends JpaRepository<T, Long>, JpaSpecificationExecutor<T> { ... }
// usage: in some service class
#Autowired
private PostRepository<Article> articleRepository;
...
public void someMethod {
...
// error here
articleRepository.findAll(ArticleSpecifications.withCategory("news"), pageable);
...
}
Error message:
java.lang.IllegalArgumentException: Unable to locate Attribute with the the given name [category] on this ManagedType [com.gladdev.galahad.base.BaseEntity]
Just trying to understand here why it tries to look up "category" in BaseEntity.
Every Specification accessing attributes defined in Post works just fine.
Is it some spring jpa specification bug or I missed something?
You can use the CriteriaBuilder.treat() method.
In Criteria API, downcasting an entity to a subclass entity can be performed by using one of the CriteriaBuilder.treat() methods:
See https://docs.oracle.com/javaee/7/api/javax/persistence/criteria/CriteriaBuilder.html#treat-javax.persistence.criteria.Root-java.lang.Class-
public static Specification<Article> withCategory(String category) {
return (root, query, criteriaBuilder) -> {
Root<Article> article = criteriaBuilder.treat(root, Article.class);
return criteriaBuilder.equal(article.get("category"), category);
};
}
Does anyone have any idea how to get a single column using Spring Data JPA? I created a repository like below in my Spring Boot project, but always get the {"cause":null,"message":"PersistentEntity must not be null!"} error when accessing the Restful URL.
#RepositoryRestResource(collectionResourceRel = "users", path = "users")
public interface UsersRepository extends CrudRepository<Users, Integer> {
#Query("SELECT u.userName FROM Users u")
public List<String> getUserName();
}
Then if I access the Restful URL like ../users/search/getUserName, I get the error:
{"cause":null,"message":"PersistentEntity must not be null!"}
Create a Projection interface
public interface UserNameOnly {
String getUserName();
}
Then in your repository interface return that type instead of the user type
public interface UserRepository<User> extends JpaRepository<User,String> {
List<UsernameOnly> findNamesByUserNameNotNull();
}
The get method in the projection interface must match a get method of the defined type on the JPA repository, in this case User.
The "findBySomePropertyOnTheObjectThatIsNotNull" allows you to get a List of the entities (as opposed to an Iterable) based on some criteria, which for a findAll can simply be if the unique identifier (or any other NonNull field) is not null.
Concept is : In your entity class create a constructor with only required instant variables. And use that constructor in the repository method shown below.
Lets say you have a interface Repository like below
Repository implementation:
public interface UserRepository<User> extends JpaRepository<User,String>
{
#Query(value = "select new com.org.User(usr.userId) from User usr where usr.name(:name)")
List<User> findUserIdAlone(#Param("name") String user);
}
In Controller
#RestController
public class UserController
{
#Autowired
private UserRepository<User> userRepository;
#Res
public ResponseEntity<User> getUser(#PathVariable("usrname") String userName)
{
User resultUser = usrRepository.findUserIdAlone(userName);
return ResponseEntity.ok(resultUser);
}
}
public class User
{
private String userId,userName;
public User(String userId)
{
this.userId=userId;
}
// setter and getters goes here
}
This Works for me.
public interface UserDataRepository extends JpaRepository<UserData, Long> {
#Query(value = "SELECT emp_name FROM user_data", nativeQuery = true)
public List<Object[]> findEmp_name();
}
System.out.println("data"+ userDataRepository.findEmp_name());
The above line gave me this result :
data[abhijeet, abhijeet1, abhijeet2, abhijeet3, abhijeet4, abhijeet5]
If you want to only return a single column you should look at Projections and Excerpts which will allow you to filter specific columns and other things that are usefule.
If you need list all of the users, try select userName from Users, if you need one user use "where" look at spring data JPA http://docs.spring.io/spring-data/jpa/docs/current/reference/html/ , try change CrudRepository to JpaRepository
It is possible to provide custom implementations of methods in a Spring Data JPA repository, which enables complete control on queries and return types. The approach is as follows:
Define an interface with the desired method signatures.
Implement the interface to achieve the desired behavior.
Have the Repository extend both JpaRepository and the custom interface.
Here is a working example that uses JpaRepository, assuming a user_table with two columns, user_id and user_name.
UserEntity class in model package:
#Entity
#Table(name = "user_table")
public class UserEntity {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
#Column(name = "user_id")
private Long userId;
#Column(name = "user_name")
private String userName;
protected UserEntity() {}
public UserEntity(String userName) {
this.userName = userName;
// standard getters and setters
}
Define interface for the custom repository in the repository package:
public interface UserCustomRepository {
List<String> findUserNames();
}
Provide implementation class for the custom interface in the repository package:
public class UserCustomRepositoryImpl implements UserCustomRepository {
// Spring auto configures a DataSource and JdbcTemplate
// based on the application.properties file. We can use
// autowiring to get a reference to it.
JdbcTemplate jdbcTemplate;
#Autowired
public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
// Now our custom implementation can use the JdbcTemplate
// to perform JPQL queries and return basic datatypes.
#Override
public List<String> findUserNames() throws DataAccessException {
String sql = "SELECT user_name FROM user_table";
return jdbcTemplate.queryForList(sql, String.class);
}
}
Finally, we just need to have the UserRepository extend both JpaRepository and the custom interface we just implemented.
public interface UserRepository extends JpaRepository<UserEntity, Long>, UserCustomRepository {}
Simple test class with junit 5 (assuming the database is initially empty):
#SpringBootTest
class UserRepositoryTest {
private static final String JANE = "Jane";
private static final String JOE = "Joe";
#Autowired
UserRepository repo;
#Test
void shouldFindUserNames() {
UserEntity jane = new UserEntity(JANE);
UserEntity joe = new UserEntity(JOE);
repo.saveAndFlush(jane);
repo.saveAndFlush(joe);
List<UserEntity> users = repo.findAll();
assertEquals(2, users.size());
List<String> names = repo.findUserNames();
assertEquals(2, names.size());
assertTrue(names.contains(JANE));
assertTrue(names.contains(JOE));
}
}
Can I use Method Injection Lookup -- with a entity class?.I use Spring+JPA+Hibernate. This allow to inject a prototype bean into a singleton bean.Is this also possible with entity beans?A is prototype scoped bean.I want to put A(#Entity) into a class B (ex. DAO) with scope=singleton.Thanks
#Entity
public class A(){
private String name;
private String surname;
...//get and set
}//A
public interface DAO{
public void method();
}//DAO
public class DAOImpl implements DAO{
private A object_a;
public void method(){
//In this method I use everytime a new istance of A
}//method
}//DAOImpl
You can use #Embedded to include your sub bean, and use in your sql.
#Entity
public class User(){
private String name;
#Embedded
private Address address;
#Bean(scope=DefaultScopes.PROTOTYPE)
public User() {
}
...//get and set
}
#Entity
public class Address(){
private String name;
...//get and set
}
public interface UserRepository extends JpaRepository<User, Long> {
#Query(value = "select u from users u where u.address.name = :addressName")
List<Blog> findUserByAddress(#Param("addressName") String addressName);
}
I just want to have a comment for what I've learned from dozens of samples about Generic DAO design-pattern. I added an inheritance hierarchy between POJO classes, DAO interfaces, and DAO implementations please see codes below
Legend:
DAOs (From Parent to children)
DAO implementations (From Parent to Children)
POJO classes (From Parent to Children)
The Data Acess Objects (Interfaces)
The GenericDAO interface
public interface GenericDAO<T> {
... some crud operations common to all objets
}
The PersonDAO interface
public interface PersonDAO<T extends Person> extends GenericDAO<T> {
... some operations unique to a person
}
The StudentDAO interface
public interface StudentDAO extends PersonDAO<Student> {
... some operations unique to a student
}
The Implementations
The GenericDAO Implementation
#Repository("genericDAO")
public class GenericDAOImpl<T extends Person> implements GenericDAO<T> {
private Class<T> type;
#SuppressWarnings("unchecked")
public GenericDAOImpl() {
this.type = (Class<T>) GenericTypeResolver.resolveTypeArgument(getClass(), GenericDAO.class);
System.out.println(type);
}
#Resource(name = "sessionFactory")
protected SessionFactory sessionFactory;
#Transactional
#Override
public Integer save(T entity) {
return (Integer) sessionFactory.getCurrentSession().save(entity);
}
#SuppressWarnings("unchecked")
#Transactional
#Override
public T get(Integer id) {
return (T) sessionFactory.getCurrentSession().get(type, id);
}
}
The PersonDAO implementation
#Repository ("personDAO")
public class PersonDAOImpl<T extends Person> extends GenericDAOImpl<T> implements PersonDAO<T> {
.. implemented methods for person
}
The StudentDAO implementation
#Repository("studentDAO")
public class StudentDAOImpl extends PersonDAOImpl<Student> implements StudentDAO {
.. implemented methods for student
}
The POJO Classes (Hibernate Annotated)
The Person Class (Parent Abstract Class)
#MappedSuperclass
public abstract class Person {
#Id
#GeneratedValue
#Column (name = "id")
private int id;
#Column (name = "name")
private String name;
#Column (name = "age")
private int age;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
The concrete class (Student)
#Entity
#Table(name = "STUDENT")
public class Student extends Person {
#Column(name = "school")
private String school;
public Student() {
}
public Student(String school) {
this.school = school;
}
public String getSchool() {
return school;
}
public void setSchool(String school) {
this.school = school;
}
}
I've been thinking about how am I going to construct a design-pattern between POJOs and DAO objects for days, Until I've come up with these design based on everything I've learned from different resources around the web. I've come up with the idea of DAO and DAO implementation inheritance based on the inheritance of the POJOs.
is this a good practice? reflecting the hierarchy of the POJOs and do it in DAOs?
am I doing something wrong about here with my design? because I have a complete program that
saves and retrieves my objects from the database without any problem
I'm open to any suggestion or corrections. Thank you in advance!!!
Not a comment on the design, but... have you consider using Spring Spring Data Jpa, which allows you to:
write your repository interfaces, including custom finder methods, and Spring will provide the implementation automatically.
I'm experiencing some strange behavior when I'm looking up node entities with Spring Data Neo4j (SDN). If I use GraphRepository.findOne(long) it will return an entity with that identifier even though the entity is not of the same type.
This is what my (very) simplified entity structure looks like:
#NodeEntity
protected abstract class BaseEntity {
#GraphId
private Long id;
#JsonIgnore
#RelatedTo(type = RelationType.ENTITY_AUDIT)
private Audit audit;
}
#NodeEntity
public final class Person extends BaseEntity {
#Indexed(indexType = IndexType.FULLTEXT)
private String firstName;
#Indexed(indexType = IndexType.FULLTEXT)
private String lastName;
}
#NodeEntity
public class Audit extends BaseEntity {
#RelatedTo(type = RelationType.ENTITY_AUDIT, direction = Direction.INCOMING)
private BaseEntity parent;
private Long date;
private String user;
}
For every entity type, I've created repositories like this:
#Repository
public interface PersonRepository extends GraphRepository<Person> {}
#Repository
public interface AuditRepository extends GraphRepository<Audit> {}
I've got an abstract base class for my service layer classes. That is what they roughly look like:
public abstract class MyServiceImpl<T extends BaseEntity> implements MyService<T> {
private GraphRepository<T> repository;
public MyServiceImpl(final GraphRepository<T> repository) {
this.repository = repository;
}
#Override
public T read(final Long identifier) throws EntityNotFoundException {
return repository.findOne(identifier);
}
#Override
public T create(final T entity) {
return repository.save(entity);
}
}
#Service
public class PersonServiceImpl extends MyServiceImpl<Person> implements PersonService {
private PersonRepository personRepository;
#Autowired
public PersonServiceImpl(final PersonRepository personRepository) {
super(personRepository);
this.personRepository = personRepository;
}
}
When I execute the following code, the result is not as expected:
Person person = new Person();
person.setFirstName("Test");
person.setLastName("Person");
personService.create(person);
// suppose the person identifier is 1L
final Audit audit = auditRepository.findOne(1L);
You'd expect that the AuditRepository would return null, but this in not the case. Instead, it returns an Audit with identifier 1L and null in all of its properties. It seems that as long as there's a node that corresponds to a given identifier, it will be returned, no mather what its type is. If Person and Audit would have had matching property names, they would contain their values too... Is all this expected behavior, or am I missing something?
For now, I've solved this problem with the code below, where I do the type check myself.
public abstract class MyServiceImpl<T extends BaseEntity> implements MyService<T> {
private GraphRepository<T> repository;
public MyServiceImpl(final GraphRepository<T> repository) {
this.repository = repository;
}
#Override
public T read(final Long identifier) throws EntityNotFoundException {
return get(identifier);
}
protected T get(final Long identifier) throws EntityNotFoundException {
final T entity = repository.findOne(identifier);
final Class<T> type = getServiceType();
if (entity == null || !(type.equals(repository.getStoredJavaType(entity)))) {
throw new EntityNotFoundException(type, identifier);
}
return entity;
}
#SuppressWarnings("unchecked")
private Class<T> getServiceType() {
return (Class<T>) ((ParameterizedType) getClass().getGenericSuperclass())
.getActualTypeArguments()[0];
}
}
If you need more configuration, please let me know.
My framework versions are:
<spring.version>3.2.0.RC1</spring.version>
<neo4j.version>1.8</neo4j.version>
<spring.data.neo4j.version>2.1.0.RELEASE</spring.data.neo4j.version>
we had that behavior before that it failed on the wrong entity type being returned, we changed that behavior so that the type you provide is used to automatically project the node to.
public <S extends PropertyContainer, T> T createEntityFromStoredType(S state, MappingPolicy mappingPolicy) {..}
template. createEntityFromStoredType(node, null) will get you the object with the stored state.
public Class getStoredJavaType(Object entity) {}
gives you the stored class for a node or relationship (or entity)
We had a discussion of changing the behavior back and failing esp. in Repositories.
The question is, what should happen then? An Exception? A Null result? ...
In general if you provide a raw node-id that is valid, returning an error or Null doesn't seem to be like a correct answer either?