I'm using Spring MVC with Spring data.
Simple example of my problem:
My dao Service class:
#Service
#AllArgsConstructor
#Transactional
public class FooService{
private FooRepository fooRepo;
public Foo save(Foo foo){
return fooRepo.save(foo);
}
}
and controller:
#Controller
#AllArgsConstructor
#Transactional //if I remove this, method add does not save a foo.
//But I don't understand why, because FooService already has #Transactional annotation
public class FooController{
private FooService fooService;
#PostMapping("/add")
public String add(#RequestParam("programName") String programName, #RequestParam("id") long id){
Foo foo = fooService.findById(id).get();
foo.setProgramName(programName);
fooService.save(foo);
return "somePage";
}
}
If I remove #Transaction annotation from controller class, method save will not update foo object.
And I don't understand why I should mark controller by #Transactional annotation if I already mark service class by this annotation?
############ UPDATE ####################
Simple detailed description:
I have Program and Education entities. One Program has many Education, Education entity has foreign key program_id.
There is a page with Program form, there are fields: program id, program theme,..., and field with a list of education id separated by commas.
I'm trying to update the education list at the program, so I add a new education id at the page form and click save. Through debugger I see, that new education has appeared in the program, but changes do not appear in the database.
#Controller
#RequestMapping("/admin/program")
#AllArgsConstructor //this is lombok, all services autowired by lombok with through constructor parameters
#Transactional//if I remove this, method add does not save a foo.
//But I don't understand why, because FooService already has #Transactional annotation
public class AdminProgramController {
private final ProgramService programService;
private final EducationService educationService;
#PostMapping("/add")
public String add(#RequestParam("themeName") String themeName, #RequestParam("orderIndex") int orderIndex,
#RequestParam(value = "educationList", defaultValue = "") String educationList,
#RequestParam(value = "practicalTestId") long practicalTestId){
saveProgram(themeName, orderIndex, educationList, practicalTestId);
return "adminProgramAdd";
private Program saveProgram(long programId, String themeName, int orderIndex, String educationList, long practicalTestId){
List<Long> longEducationList = Util.longParseEducationList(parsedEducationList); //this is list of Education id separeted by commas that I load from page form
//creating new program and set data from page form
Program program = new Program();
program.setId(programId);
program.setThemeName(themeName);
program.setOrderIndex(orderIndex);
//starting loop by education id list
longEducationList.stream()
.map(educationRepo::findById)
.filter(Optional::isPresent)
.map(Optional::get)
.forEach(edu->{
//linking program and education
program.getEducationList().add(edu);
edu.setProgram(program);
});
//saving new program or updating by service if there is one already
Program savedProgram = programService.save(program);
//saving education with updated program
for(Education edu : savedProgram.getEducationList())
{
educationService.save(edu);
}
return savedProgram;
}
}
ProgramService:
#Service
#AllArgsConstructor //this is lombok, all services autowired by lombok with throught constructor parameters
#Transactional
public class ProgramService {
private ProgramRepo programRepo;
//other code here.....
public Program save(Program program) {
Optional<Program> programOpt = programRepo.findById(program.getId());
//checking if the program is already exist, then update it paramateres
if(programOpt.isPresent()){
Program prgm = programOpt.get();
prgm.setThemeName(program.getThemeName());
prgm.setOrderIndex(program.getOrderIndex());
prgm.setPracticalTest(program.getPracticalTest());
prgm.setEducationList(program.getEducationList());
return programRepo.save(prgm);
}
//if not exist then just save new program
else{
return programRepo.save(program);
}
}
}
Education service
#Service
#AllArgsConstructor //this is lombok, all services autowired by lombok with throught constructor parameters
#Transactional
public class EducationService {
private EducationRepo educationRepo;
//other code here....
public Education save(Education education){
return educationRepo.save(education);
}
}
Program entity:
#Entity
#ToString(exclude = {"myUserList", "educationList", "practicalTest"})
#Getter
#Setter
#NoArgsConstructor
public class Program implements Comparable<Program>{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
#Column(name = "theme_name")
private String themeName;
#Column(name = "order_index")
private int orderIndex; //from 1 to infinity
#OneToMany(mappedBy = "program", fetch = FetchType.LAZY)
#OrderBy("orderIndex asc")
private List<Education> educationList = new ArrayList<>();
#OneToMany(mappedBy = "program", fetch = FetchType.LAZY)
private List<MyUser> myUserList = new ArrayList<>();
#OneToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "test_id")
private PracticalTest practicalTest;
public Program(int orderIndex, String themeName) {
this.orderIndex = orderIndex;
this.themeName = themeName;
}
public Program(long id) {
this.id = id;
}
//other code here....
}
Education entity:
#Entity
#ToString(exclude = {"program", "myUserList"})
#Getter
#Setter
#NoArgsConstructor
public class Education implements Comparable<Education>{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
private String link;
#Column(name = "order_index")
private int orderIndex;
private String type;
private String task;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "program_id")
private Program program;
#OneToMany(mappedBy = "education", fetch = FetchType.LAZY)
private List<MyUser> myUserList = new ArrayList<>();
public Education(String link, int orderIndex, String task, Program program) {
this.link = link;
this.orderIndex = orderIndex;
this.task = task;
this.program = program;
}
//other code here....
}
Program repo:
#Repository
public interface ProgramRepo extends CrudRepository<Program, Long> {
Optional<Program> findByPracticalTest(PracticalTest practicalTest);
Optional<Program> findByOrderIndex(int orderIndex);
List<Program> findByIdBetween(long start, long end);
}
Education repo:
#Repository
public interface EducationRepo extends CrudRepository<Education, Long> {
Optional<Education> findByProgramAndOrderIndex(Program program, int orderIndex);
#Query("select MAX(e.orderIndex) from Education e where e.program.id = ?1")
int findLastEducationIndexByProgramId(long programId);
}
I think the problem is program object created in one transaction and saved in another. That's why if I put Transactional on controller it works. There are two ways to solve the problem:
Without transactional on the controller: then I must save education object at first, because it has program id field and then save the program object.
With transactional on controller: then saving order has no matter, because saving object occurs in one transaction
Related
I have these Objects:
#Data
#Entity
#Table
#EqualsAndHashCode(callSuper = true)
public class User extends AbstractEntity implements Serializable {
private static final long serialVersionUID = -55089179131569489L;
private String username;
private String email;
private boolean admin;
private String name;
private String surname;
#OneToMany(mappedBy = "owner")
private List<Ad> ads;
}
and
#Entity
#Table
#Data
#EqualsAndHashCode(callSuper = true)
public class Ad extends AbstractEntity implements Serializable {
private static final long serialVersionUID = -4590938091334150254L;
private String name;
private String description;
private double price;
#Enumerated(EnumType.STRING)
private Category category;
#ManyToOne(cascade = CascadeType.ALL,fetch = FetchType.EAGER)
#JoinColumn(name = "OWNER_ID")
private User owner;
}
When I try to execute a POST with an object of type Ad.class with inside an existing object of type User.class (already in the Database) the service saves only the Ad object and the join column "OWNER_ID" remains empty.
I think that the mapping is correct. Could you help me to figure out the problem?
This is my Repository:
#Repository
#Transactional(readOnly = true)
public interface AdRepository extends PagingAndSortingRepository<Ad, String>
{}
and this is my RestRepository
#RepositoryRestResource(collectionResourceRel = "ad", path = "ad")
public interface AdRestRepository extends PagingAndSortingRepository<Ad, String> {}
If I step back a little and generalize your problem,
You are trying to POST a sub resource and expect both actions of
making a new resource (Ad)
making association with the owner (User)
to be happened with a single call.
But unfortunately spring-data-rest does not support such a behavior. You need 2 calls to do this.
One to make the resource (Ad) => POST to /ads with actual payload
Second to make the association => POST to users/{ownerId} with the hateoas link of the resource created by the first call.
Take a look at this section of official documentation.
I have 2 entities in my DB with one-to-one one directional mapping:
User and PasswordResetToken. The idea behind this is to create new token each time user requests password reset and store only the latest one.
Below are my entities:
#Entity
#Table(name = "USERS")
#Getter #Setter
public class User implements Serializable {
#Id
#Column(name = "ID")
#GeneratedValue(strategy = GenerationType.AUTO, generator = "usersSeq")
#SequenceGenerator(name = "usersSeq", sequenceName = "SEQ_USERS", allocationSize = 1)
private long id;
#Column(name = "NAME")
private String name;
#Column(name = "PASSWORD")
private String password;
#Column(name = "EMAIL")
private String email;
#Column(name = "ROLE")
private Integer role;
}
///...
#Entity
#Table(name = "PASSWORD_RESET_TOKENS")
#Getter
#Setter
public class PasswordResetToken implements Serializable {
private static final int EXPIRATION = 24;
#Column(name = "TOKEN")
private String token;
#Id
#OneToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
#JoinColumn(nullable = false, name = "user_id")
private User user;
#Column(name = "EXPIRY_DATE")
private Instant expiryDate;
public PasswordResetToken() {
}
public void setExpiryDate(ZonedDateTime expiryDate) {
this.expiryDate = expiryDate.plus(EXPIRATION, ChronoUnit.HOURS).toInstant();
}
}
Also, I have DTOs created for both of them to pass them around my app.
Code snippets:
#Getter #Setter
public class PasswordResetTokenModel {
private String token;
private ZonedDateTime expiryDate;
private UserModel user;
}
UserModel is also used for Spring Security
#Getter
#Setter
public class UserModel extends User {
public UserModel(String username, String password, Collection<? extends GrantedAuthority> authorities) {
super(username, password, authorities);
}
private long id;
private String name;
public String getEmail() {
return this.getUsername();
}
}
For population I've created 2 populators:
#Component
public class UserPopulatorImpl implements UserPopulator {
#Autowired
UserDetailsService userDetailsService;
#Override
public UserModel populateToDTO(User user) {
UserModel userModel = new UserModel(user.getEmail(), user.getPassword(), userDetailsService.getAuthorities(user.getRole()));
userModel.setId(user.getId());
return userModel;
}
#Override
public User populateToDAO(UserModel userModel) {
User user = new User();
user.setEmail(userModel.getEmail());
user.setName(userModel.getName());
user.setPassword(userModel.getPassword());
//TODO: change it!
user.setRole(1);
return user;
}
}
//...
#Component
public class PasswordResetTokenPopulatorImpl implements PasswordResetTokenPopulator {
#Autowired
UserPopulator userPopulator;
#Override
public PasswordResetTokenModel populateToDTO(PasswordResetToken passwordResetToken) {
PasswordResetTokenModel passwordResetTokenModel = new PasswordResetTokenModel();
passwordResetTokenModel.setUser(userPopulator.populateToDTO(passwordResetToken.getUser()));
passwordResetTokenModel.setToken(passwordResetToken.getToken());
passwordResetTokenModel.setExpiryDate(ZonedDateTime.ofInstant(passwordResetToken.getExpiryDate(), ZoneId.systemDefault()));
return passwordResetTokenModel;
}
#Override
public PasswordResetToken populateToDAO(PasswordResetTokenModel passwordResetTokenModel) {
PasswordResetToken passwordResetToken = new PasswordResetToken();
passwordResetToken.setExpiryDate(passwordResetTokenModel.getExpiryDate());
passwordResetToken.setUser(userPopulator.populateToDAO(passwordResetTokenModel.getUser()));
passwordResetToken.setToken(passwordResetTokenModel.getToken());
return passwordResetToken;
}
}
I'm saving object using
sessionFactory.getCurrentSession().saveOrUpdate(token);
When I use this code, I'm getting following exception
object references an unsaved transient instance - save the transient instance before flushing: com.demo.megaevents.entities.User
There are currently 2 issues in this code:
Seems like Cascade.ALL in my OneToOne mapping is not working. If
I create separate primary key in Token class everything works almost
as expected but storing every created token in DB (more like
OneToMany relation), however I want to avoid it as I need to store
only one token per user in my DB
I don't like using new in populators, as it forces hibernate to create new object while flushing session. However, I also don't want to do another select to fetch this data from DB because just before mentioned populator I already do this query to fetch it and I think that it's an overhead.
Also, I really want to have DTOs and I don't want to remove DTO layer.
So, my questions:
What is the correct way to handle population between DTO and entities?
Are there any other improvements (probably architectural) to my solution?
Thanks a lot.
I'm not sure why you would let UserModel extend User, but I guess you did that because you didn't want to have to copy all properties from User into UserModel. Too bad, because that's what is going to be needed to have a clean separation between the entity model and data transfer model.
You get that exception because you try to persist a PasswordResetToken that has a reference to a User object with an id, but the User isn't associated with the current session. You don't have to query the user, but at least association it with the session like this:
PasswordResetToken token = // wherever you get that from
Session s = sessionFactory.getCurrentSession();
token.setUser(s.load(User.class, token.getUser().getId());
s.persist(token);
Cascading would cause the User to be created/inserted or updated via a SQL INSERT or UPDATE statement which is apparently not what you want.
You could do the Session.load() call in you populators if you want, but I'd not do that. Actually I would recommend not having populators at all, but instead create the entity objects in your service instead.
Normally you only have a few(mostly 1) ways of actually creating a new entity object, so the full extent of the transformation from DTO to entity will only be relevant in very few cases.
Most of the time you are going to do an update and for that, you should first select the existing entity and apply the fields that are allowed to be changed from the DTO on the entity object.
For providing the presentation layer with DTOs I would recommend using Blaze-Persistence Entity Views to avoid the manual mapping boilerplate and also improve performance of select queries.
I'm using spring-data-mongodb 1.8.2 (spring-boot-starter 1.3.1) and I have a fairly easy case at hand (in which I added fetch eager in desperation):
#Document(collection = "class_room")
public class ClassRoom implements Serializable {
#Id
private String id;
#NotNull
#Field("name")
private String name;
#ManyToOne**(fetch = FetchType.EAGER)**
#JoinColumn(name = "school_id")
private School school;
[...]
}
#Document(collection = "school")
public class School implements Serializable {
#Id
private String id;
#NotNull
#Field("name")
private String name;
#OneToMany(mappedBy = "school"**, fetch = FetchType.EAGER**)
private Set<Article> articles = new HashSet<>();
[...]
}
The repositories:
public interface SchoolRepository extends MongoRepository {
}
public interface ClassRoomRepository extends MongoRepository<ClassRoom,String> {
}
And the resources:
#RequestMapping(value = "/schools",
method = RequestMethod.GET,
produces = MediaType.APPLICATION_JSON_VALUE)
#Timed
public List<School> getAllSchools() {
return schoolRepository.findAll();
}
#RequestMapping(value = "/classRooms",
method = RequestMethod.GET,
produces = MediaType.APPLICATION_JSON_VALUE)
#Timed
public List<ClassRoom> getAllClassRooms() {
return classRoomRepository.findAll();
}
Now, can someone explain to me why the articles are correctly loaded when I perform the 'schoolRepository.findAll()'
but not when I perform the 'classRoomRepository.findAll()'?
And how can I make it happen?
TL;DR
A School has set of Articles
A classRoom has a School.
When I access a school directly: I see the set of Article
When access a school through a classRoom, the set of Article is empty.
Your approach to using object associations is a bit off. In Spring Data with Mongo the concepts of defining annotations to describe how associations happen is not the standard approach.
If you see the documentation here http://docs.spring.io/spring-data/data-mongo/docs/1.4.2.RELEASE/reference/html/mapping-chapter.html it helps to provide more clarity.
But to highlight, Mongo uses the concept of embedded objects and so ideally your data structure can be something like:
#Document(collection = "class_room")
public class ClassRoom implements Serializable {
#Id
private String id;
private String name;
private School school;
// Where School has the following fields and structure:
// private String id;
// private String name;
// private Set<Article> articles = new HashSet<>()
}
If you want school to be embedded in ClassRoom you leave it as above, else you can have School as a separate collection of its own. So:
#Document(collection = "school")
public class School implements Serializable {
#Id
private String id;
private String name;
private Set<Article> articles = new HashSet<>();
[...]
}
In the above School, it is a collection of its own and is not embedded in ClassRoom.
Typically, you have to just think differently from your traditional ORM approach when dealing with Mongo, or a NoSQL/Graph database.
Given a User entity with the following attributes mapped:
#Entity
#Table(name = "user")
public class User {
//...
#Id
#GeneratedValue
#Column(name = "user_id")
private Long id;
#Column(name = "user_email")
private String email;
#Column(name = "user_password")
private String password;
#Column(name = "user_type")
#Enumerated(EnumType.STRING)
private UserType type;
#Column(name = "user_registered_date")
private Timestamp registeredDate;
#Column(name = "user_dob")
#Temporal(TemporalType.DATE)
private Date dateOfBirth;
//...getters and setters
}
I have created a controller method that returns a user by ID.
#RestController
public class UserController {
//...
#RequestMapping(
value = "/api/users/{id}",
method = RequestMethod.GET,
produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<User> getUser(#PathVariable("id") Long id) {
User user = userService.findOne(id);
if (user != null) {
return new ResponseEntity<User>(user, HttpStatus.OK);
}
return new ResponseEntity<User>(HttpStatus.NOT_FOUND);
}
//...
}
A service in my business logic layer.
public class UserServiceBean implements UserService {
//...
public User findOne(Long id) {
User user = userRepository.findOne(id);
return user;
}
//...
}
And a repository in my data layer.
public interface UserRepository extends JpaRepository<User, Long> {
}
This works fine, it returns everything about the user, but I use this in several different parts of my application, and have cases when I only want specific fields of the user.
I am learning spring-boot to create web services, and was wondering: Given the current implementation, is there a way of picking the attributes I want to publish in a web service?
If not, what should I change in my implementation to be able to do this?
Thanks.
Firstly, I agree on using DTOs, but if it just a dummy PoC, you can use #JsonIgnore (jackson annotation) in User attributes to avoid serializing them, for example:
#Entity
#Table(name = "user")
public class User {
//...
#Column(name = "user_password")
#JsonIgnore
private String password;
But you can see there, since you are not using DTOs, you would be mixing JPA and Jackson annotations (awful!)
More info about jackson: https://github.com/FasterXML/jackson-annotations
I have two classes that have a one-to-many relation. When I try to access the lazily loaded collection I get the LazyInitializationException.
I have been searching the web for a while and now I know that I get the exception because the session that was used to load the class which holds the collection is closed.
However, I did not find a solution (or at least I did not understand them). Basically I have these classes:
User
#Entity
#Table(name = "user")
public class User {
#Id
#GeneratedValue
#Column(name = "id")
private long id;
#OneToMany(mappedBy = "creator")
private Set<Job> createdJobs = new HashSet<>();
public long getId() {
return id;
}
public void setId(final long id) {
this.id = id;
}
public Set<Job> getCreatedJobs() {
return createdJobs;
}
public void setCreatedJobs(final Set<Job> createdJobs) {
this.createdJobs = createdJobs;
}
}
UserRepository
public interface UserRepository extends JpaRepository<User, Long> {}
UserService
#Service
#Transactional
public class UserService {
#Autowired
private UserRepository repository;
boolean usersAvailable = false;
public void addSomeUsers() {
for (int i = 1; i < 101; i++) {
final User user = new User();
repository.save(user);
}
usersAvailable = true;
}
public User getRandomUser() {
final Random rand = new Random();
if (!usersAvailable) {
addSomeUsers();
}
return repository.findOne(rand.nextInt(100) + 1L);
}
public List<User> getAllUsers() {
return repository.findAll();
}
}
Job
#Entity
#Table(name = "job")
#Inheritance
#DiscriminatorColumn(name = "job_type", discriminatorType = DiscriminatorType.STRING)
public abstract class Job {
#Id
#GeneratedValue
#Column(name = "id")
private long id;
#ManyToOne
#JoinColumn(name = "user_id", nullable = false)
private User creator;
public long getId() {
return id;
}
public void setId(final long id) {
this.id = id;
}
public User getCreator() {
return creator;
}
public void setCreator(final User creator) {
this.creator = creator;
}
}
JobRepository
public interface JobRepository extends JpaRepository<Job, Long> {}
JobService
#Service
#Transactional
public class JobService {
#Autowired
private JobRepository repository;
public void addJob(final Job job) {
repository.save(job);
}
public List<Job> getJobs() {
return repository.findAll();
}
public void addJobsForUsers(final List<User> users) {
final Random rand = new Random();
for (final User user : users) {
for (int i = 0; i < 20; i++) {
switch (rand.nextInt(2)) {
case 0:
addJob(new HelloWorldJob(user));
break;
default:
addJob(new GoodbyeWorldJob(user));
break;
}
}
}
}
}
App
#Configuration
#EnableAutoConfiguration
#ComponentScan
public class App {
public static void main(final String[] args) {
final ConfigurableApplicationContext context = SpringApplication.run(App.class);
final UserService userService = context.getBean(UserService.class);
final JobService jobService = context.getBean(JobService.class);
userService.addSomeUsers(); // Generates some users and stores them in the db
jobService.addJobsForUsers(userService.getAllUsers()); // Generates some jobs for the users
final User random = userService.getRandomUser(); // Picks a random user
System.out.println(random.getCreatedJobs());
}
}
I have often read that the session has to be bound to the current thread, but I don't know how to do this with Spring's annotation based configurations.
Can someone point me out how to do that?
P.S. I want to use lazy loading, thus eager loading is no option.
Basically, you need to fetch the lazy data while you are inside of a transaction. If your service classes are #Transactional, then everything should be ok while you are in them. Once you get out of the service class, if you try to get the lazy collection, you will get that exception, which is in your main() method, line System.out.println(random.getCreatedJobs());.
Now, it comes down to what your service methods need to return. If userService.getRandomUser() is expected to return a user with jobs initialized so you can manipulate them, then it's that method's responsibility to fetch it. The simplest way to do it with Hibernate is by calling Hibernate.initialize(user.getCreatedJobs()).
Consider using JPA 2.1, with Entity graphs:
Lazy loading was often an issue with JPA 2.0. You had to define at the entity FetchType.LAZY or FetchType.EAGER and make sure the relation gets initialized within the transaction.
This could be done by:
using a specific query that reads the entity
or by accessing the relation within business code (additional query for each relation).
Both approaches are far from perfect, JPA 2.1 entity graphs are a better solution for it:
http://www.thoughts-on-java.org/jpa-21-entity-graph-part-1-named-entity/
http://www.thoughts-on-java.org/jpa-21-entity-graph-part-2-define/
You have 2 options.
Option 1 : As mentioned by BetaRide, use the EAGER fetching strategy
Option 2 : After getting the user from database using hibernate, add the below line in of code to load the collection elements:
Hibernate.initialize(user.getCreatedJobs())
This tells hibernate to initialize the collection elements
Change
#OneToMany(mappedBy = "creator")
private Set<Job> createdJobs = new HashSet<>();
to
#OneToMany(fetch = FetchType.EAGER, mappedBy = "creator")
private Set<Job> createdJobs = new HashSet<>();
Or use Hibernate.initialize inside your service, which has the same effect.
For those who have not the possibility to use JPA 2.1 but want to keep the possibility to return a entity in their controller (and not a String/JsonNode/byte[]/void with write in response):
there is still the possibility to build a DTO in the transaction, that will be returned by the controller.
#RestController
#RequestMapping(value = FooController.API, produces = MediaType.APPLICATION_JSON_VALUE)
class FooController{
static final String API = "/api/foo";
private final FooService fooService;
#Autowired
FooController(FooService fooService) {
this.fooService= fooService;
}
#RequestMapping(method = GET)
#Transactional(readOnly = true)
public FooResponseDto getFoo() {
Foo foo = fooService.get();
return new FooResponseDto(foo);
}
}
You should enable Spring transaction manager by adding #EnableTransactionManagement annotation to your context configuration class.
Since both services have #Transactional annotation and default value property of it is TxType.Required, current transaction will be shared among the services, provided that transaction manager is on. Thus a session should be available, and you won't be getting LazyInitializationException.