fetch one to many side with jpql - jpa

so I have done two entities with one to many relationship,
I have one category whohas many visitors,
and this is my code:
this is the Category entity :
#Entity
public class Category implements Serializable {
private Integer id;
private String name;
private List<Visitor> visitors = new ArrayList<Visitor>();
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
#OneToMany(cascade=CascadeType.REMOVE, fetch = FetchType.LAZY, mappedBy = "category", orphanRemoval = true)
public List<Visitor> getVisitors() {
return visitors;
}
public void setVisitors(List<Visitor> visitors) {
this.visitors = visitors;
}
}
and here is the Visitor Entity :
#Entity
public class Visitor extends User {
private String passport;
private String citizenship;
private String gender;
private Company company;
private Category category;
public String getPassport() {
return passport;
}
public void setPassport(String passport) {
this.passport = passport;
}
public String getCitizenship() {
return citizenship;
}
public void setCitizenship(String citizenship) {
this.citizenship = citizenship;
}
#ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
public Category getCategory() {
return category;
}
public void setCategory(Category category) {
this.category = category;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
#ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
public Company getCompany() {
return company;
}
public void setCompany(Company company) {
this.company = company;
}
and here is the service method who list all the visitors and works fine :
public List<Visitor> findAllVisitors() {
return em.createQuery(
"SELECT v from Visitor v left join fetch v.category",
Visitor.class).getResultList();
}
with this method I can list all the visitors each with his category object associated,
now the problem is in the other side of the relationship ,
here is the method who list the categories each with their visitors list :
public List<Category> findAllCategories() {
return em.createQuery("select c from Category c",
Category.class).getResultList();
}
I want to get the list of all the categories but when I call this method in a REST call , I get this result :
I want just to get a simple list of categories (id and name).
what is wrong in my code please help me i am confused.
UPDATE:
this is how I get JSON from persistence context with RESTful method :
#Inject
private CategoryServiceLocal categoryServiceLocal;
#GET
#Produces(MediaType.APPLICATION_JSON)
public List<Category> dofindAllCategories() {
return categoryServiceLocal.findAllCategories();
}

You have a lazy association from Category to visitors. To load all visitors you need to use left join fetch too.
select c from Category c left join fetch c.visitors
Please, use additional annotations to control how to JSON generated
Infinite Recursion with Jackson JSON and Hibernate JPA issue

Related

Want to automatically insert current Date in the table When a post Request is made

I have a User Entity and an Order Entity.
One of the field in order entity is date.
Till now i have the user enter the date.
Now i want that at the time post request is made the date is automatically set to the current date and stored in the database.
Tried using #Prepersist annotation But since this is my first API that i am developing using springBoot , I don't really know how to use it.
User Entity
#Entity
public class User {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private BigInteger id;
#NotEmpty(message = "Name is compulsory")
#Pattern(regexp="^[A-Za-z]*[A-Za-z-'. ]*[A-Za-z]*$",message = "Name has invalid characters")
private String username;
//#NotEmpty(message = "Phone Number is compulsary")
#Range(min = 6400000000L ,max=9999999999L)
private Long phoneNumber;
#NotEmpty(message = "Address is compulsary")
private String address;
public User(){}
public User(BigInteger id, String username, Long phoneNumber, String address) {
super();
this.id = id;
this.username = username;
this.phoneNumber = phoneNumber;
this.address = address;
}
public BigInteger getId() {
return id;
}
public void setId(BigInteger id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Long getPhoneNumber() {
return phoneNumber;
}
public void setPhoneNumber(Long phoneNumber) {
this.phoneNumber = phoneNumber;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
Order Entity
#Entity
public class Orders {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private BigInteger id;
#CreationTimestamp
#Temporal(TemporalType.TIMESTAMP)
private Date date;
#ManyToOne
private User user;
public Orders(){}
public Orders(BigInteger id, Date date,BigInteger userId) {
super();
this.id = id;
this.date = date;
this.user=new User(userId," ",0000000000L," ");
}
public BigInteger getId() {
return id;
}
public void setId(BigInteger id) {
this.id = id;
}
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
}
Order Controller
#RestController
public class OrdersController {
#Autowired
private OrdersService ordersService;
#ApiOperation(value="Show all orders")
#RequestMapping("/orders")
public Iterable<Orders> getAllOrders()
{
return ordersService.getAllOrders();
}
#ApiOperation(value="Show a particular Order")
#RequestMapping("/orders/{orderId}")
public Orders getOrderById(#PathVariable BigInteger orderId)
{
return ordersService.getOrderById(orderId);
}
#ApiOperation(value="Show all orders of a particular User")
#RequestMapping("/users/{id}/orders")
public List<Orders> getOrders(#PathVariable BigInteger id) {
return ordersService.getOrders(id);
}
#ApiOperation(value="Show an order for a User")
#RequestMapping("/users/{userId}/orders/{id}")
public Orders getOrder(#PathVariable BigInteger id){
return ordersService.getOrder(id);
}
#ApiOperation(value="Adds a new Order")
#RequestMapping(method = RequestMethod.POST,value = "/users/{userId}/orders")
public Orders addOrder(#PathVariable BigInteger userId,#RequestBody Orders orders) {
orders.setUser(new User(userId," ",0000000000L," "));
return ordersService.addOrder(orders);
}
#ApiOperation(value="Alter an Order")
#RequestMapping(method = RequestMethod.PUT, value="/users/{userId}/orders/{id}")
public Orders updateOrder(#RequestBody Orders order,#PathVariable BigInteger id,#PathVariable BigInteger userId)throws Exception {
order.setUser(new User(userId," ",0000000000L," "));
return ordersService.updateOrder(order, id);
}
#ApiOperation(value="Delete an Order")
#RequestMapping(method = RequestMethod.DELETE, value="/orders/{id}")
public void deleteOrder(#PathVariable BigInteger id){
ordersService.deleteOrder(id);
}
}
#PrePersist is a JPA annotation and therefore should work in all compatible persistence frameworks. It indicates a method that should be invoked on particular entity lifecycle event. (Other events are well documented in the Hibernate user guide here).
Add this to your entity:
#Temporal(TemporalType.TIMESTAMP)
#Column(nullable = false)
private Date timestamp;
#PrePersist
private void onCreate() {
timestamp = new Date();
}
As for assigning/creating the entity in the controller, it is a good practice to use DTO (data transfer objects) in your controller (#RequestBody OrderDto orderDto) and then use some method to populate a new entity instance with those values. Most common options are
modelmapper
manually
...
Order o = new Order();
o.user = userDao.findById(orderDto.getUserId());
...
// persist o

Spring boot CrudRepository save - exception is org.hibernate.type.SerializationException: could not serialize

Not sure why I have an issue here, but when I save with a CrudRepository with these objects, I get the SerializationException (with no further information). Can someone take a look at my objects and offer me some insight into why they can't serialize? My pom.xml is attached last as well in case that helps somehow. I'm using a Postgres database.
EDIT: The database and now - tables are created, but objects are not creating rows.
The actual CrudRepository interface:
public interface AccountRepository extends CrudRepository<ZanyDishAccount, String> {}
ZanyDishAccount entity:
#Entity
public class ZanyDishAccount {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private Long id; // internal id of the customer account for a Zany Dish subscription
private String status;
#OneToOne(cascade=CascadeType.ALL, fetch = FetchType.EAGER)
#JoinColumn(name = "company_id")
private Company company;
#OneToOne(cascade=CascadeType.ALL, fetch = FetchType.EAGER)
#JoinColumn(name = "order_id")
private Order order;
public ZanyDishAccount() {}
public ZanyDishAccount(Company company, Order order) {
this.company = company;
this.order = order;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public Company getCompany() {
return company;
}
public void setCompany(Company company) {
this.company = company;
}
public Order getOrder() {
return order;
}
public void setOrder(Order order) {
this.order = order;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
#Override
public String toString()
{
return "ClassPojo [id = "+id+ ", company = " + company + ", status = " + status + "]";
}
}
Company entity:
#Entity
public class Company {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
Long id;
private String phoneNumber;
private String website;
private String name;
private String uuid;
private String country;
public Company() {}
public Company(String phoneNumber, String website, String name, String uuid, String country) {
this.phoneNumber = phoneNumber;
this.website = website;
this.uuid = uuid;
this.country = country;
}
public String getPhoneNumber ()
{
return phoneNumber;
}
public void setPhoneNumber (String phoneNumber)
{
this.phoneNumber = phoneNumber;
}
public String getWebsite ()
{
return website;
}
public void setWebsite (String website)
{
this.website = website;
}
public String getName ()
{
return name;
}
public void setName (String name)
{
this.name = name;
}
public String getUuid ()
{
return uuid;
}
public void setUuid (String uuid)
{
this.uuid = uuid;
}
public String getCountry ()
{
return country;
}
public void setCountry (String country)
{
this.country = country;
}
#Override
public String toString()
{
return "ClassPojo [phoneNumber = "+phoneNumber+", website = "+website+", name = "+name+", uuid = "+uuid+", country = "+country+"]";
}
}
Order entity:
#Entity
#Table(name = "_order")
public class Order {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
Long id;
private String pricingDuration;
private Items[] items;
private String editionCode;
public Order() {}
public Order(String pricingDuration, Items[] items, String editionCode) {
this.pricingDuration = pricingDuration;
this.items = items;
this.editionCode = editionCode;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getPricingDuration ()
{
return pricingDuration;
}
public void setPricingDuration (String pricingDuration)
{
this.pricingDuration = pricingDuration;
}
public Items[] getItems ()
{
return items;
}
public void setItems (Items[] items)
{
this.items = items;
}
public String getEditionCode ()
{
return editionCode;
}
public void setEditionCode (String editionCode)
{
this.editionCode = editionCode;
}
#Override
public String toString()
{
return "ClassPojo [pricingDuration = "+pricingDuration+", items = "+items+", editionCode = "+editionCode+"]";
}
}
Thanks for your help!
Mike
Hm, this seems multi-faceted. Let's see if I can help at all. Last thing first...
No tables being created automatically.
I would take a look at this section in Spring's docs for the most basic approach: Initialize a database using Hibernate. For example, spring.jpa.hibernate.ddl-auto: create-drop will drop and re-create tables each time the application runs. Simple and easy for initial dev work. More robust would be leveraging something like Flyway or Liquibase.
Serialization issue
So without logs, and the fact that you have no tables created, the lack of a persistence layer would be the assumed culprit. That said, when you have tables and data, if you do not have a repository for all of the related tables, you'll end up with a StackOverflow error (the serialization becomes circular). For that, you can use #JsonBackReference (child) and #JsonManagedReference (parent). I have been successful using only #JsonBackReference for the child.
Items[]
I'm not sure what Item.class looks like, but that looks like an offensive configuration that I missed the first round.
Change private Items[] items; to private List<Item> items = new ArrayList<Item>();. Annotate with #ElementCollection.
Annotate Item.class with #Embeddable.

How to make a relation of same table in JPA?

Need make a relationship between same table. Example: the object "category" have subcategories and the subcategorie have other subcategorie.
In MySQL make a column and point to primary key of same table, but, howto make in JPA?
My code is:
#Entity
#Table(name = "objects")
public class JObject {
private long id;
private String name;
private JObject parentJObject;
private Set<JObject> jObjects;
public JObject(){
}
public JObject(long id){
this.id = id;
}
public JObject(String name){
this.name = name;
}
public JObject(String name, JObject parentJObject){
this.name = name;
this.parentJObject = parentJObject;
}
#Null
#JoinColumn(name="parent_object_id", referencedColumnName="id")
#ManyToOne(cascade=CascadeType.ALL)
public JObject getParentJObject() {
return parentJObject;
}
public void setParentJObject(JObject parentJObject) {
this.parentJObject = parentJObject;
}
#Null
#OneToMany(mappedBy = "parentJObject", cascade = CascadeType.ALL)
public Set<JObject> getJObjects() {
return jObjects;
}
public void setJObjects(Set<JObject> jObjects) {
this.jObjects = jObjects;
}
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
#NotNull
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
And the making objects:
JObject jObjectcategories = new JObject("Demo 1");
Set categoriesJObjects = new HashSet<JObject>(){{
add(new JObject("Demo 1.1", jObjectcategories));
}};
jObjectcategories.setJObjects(categoriesJObjects);
jObjectDao.save(new HashSet<JObject>() {{
add(jObjectcategories);
}});
But does not works. The log says:
List of constraint violations:[ ConstraintViolationImpl{interpolatedMessage='It has to be null', propertyPath=JObjects, rootBeanClass=class a.b.c.models.JObject, messageTemplate='{javax.validation.constraints.Null.message}'} ]
You need to be consistent in where you place your JPA annotations: either all on fields, or all on getters. But not mixed as you're doing.
The OneToOne should be a ManyToOne according to your description, since several objects share the same parent.
And the cascade ALL doesn't make sense: you don't want to delete a parent when a child is deleted.

JPA Cascade Persist Error

I have a One-to-Many relationship: A ProductCategory can contains many Product. This is the code:
#Entity
public class Product implements Serializable {
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
private String id;
#Column(name="ProductName")
private String name;
private BigDecimal price;
private String description;
#ManyToOne
#JoinColumn(name="UserId")
private User user;
#ManyToOne
#JoinColumn(name="Category")
private ProductCategory category;
private static final long serialVersionUID = 1L;
public Product() {
super();
}
public String getId() {
return this.id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
public BigDecimal getPrice() {
return this.price;
}
public void setPrice(BigDecimal price) {
this.price = price;
}
public String getDescription() {
return this.description;
}
public void setDescription(String description) {
this.description = description;
}
public User getUser() {
return this.user;
}
public void setUser(User user) {
this.user = user;
}
public ProductCategory getCategory() {
return this.category;
}
public void setCategory(ProductCategory category) {
this.category = category;
}
}
#Entity
public class ProductCategory {
#Id
private String categoryName;
#OneToMany(cascade= CascadeType.ALL,mappedBy="category")
private List<Product> products;
public String getCategoryName() {
return categoryName;
}
public void setCategoryName(String productName) {
this.categoryName = productName;
}
public List<Product> getProducts() {
return products;
}
public void setProducts(List<Product> products) {
this.products = products;
}
}
This is Servlet code which use the 2 entities:
String name = request.getParameter("name");
BigDecimal price = new BigDecimal(request.getParameter("price"));
String description = request.getParameter("description");
ProductCategory category = new ProductCategory();
category.setCategoryName(request.getParameter("category"));
Product product = new Product();
product.setName(name);
product.setPrice(price);
product.setDescription(description);
product.setCategory(category);
User user = userManager.findUser("Meow");
product.setUser(user);
productManager.createProduct(product); // productManager is an EJB injected by container
And this is the error:
java.lang.IllegalStateException: During synchronization a new object was found through a relationship that was not marked cascade PERSIST
Why does this error happen? I marked the field as "cascade = CascadeType.All"!
You're trying to save a product. And this product is linked to a category. So when JPA saves the product, its category must already exist, or there must be a cascade configured so that persisting the product cascades to persisting its category.
But you don't have such a cascade. What you have is a cascade saying that any operation done on a category cascades to its list of products.

Loading child entities in parent/child relationship with JPA

My domain has a Category entity which has a biderectional relationship on itself. Each category can have a parent and children.
#Entity
public class Category implements DomainObject {
private Long id;
private Integer version;
private String name;
private Category parent;
private Set<Category> children;
#Override
#Id
#GeneratedValue
public final Long getId() {
return id;
}
#Version
public Integer getVersion() {
return version;
}
public void setVersion(Integer version) {
this.version = version;
}
public void setId(Long id) {
this.id = id;
}
#Column(unique=true, nullable=false)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
#ManyToOne
public Category getParent() {
return parent;
}
public void setParent(Category parent) {
this.parent = parent;
}
#OneToMany
#JoinColumn(name = "parent_id")
public Set<Category> getChildren() {
return children;
}
public void setChildren(Set<Category> children) {
this.children = children;
}
}
I have created the following query to fetch the "root" categories with their direct (level 1) children.
select distinct c from Category c left join fetch c.children where c.parent is null order by c.name
This actually works. My question is: why do I need the "JoinColumn" annotation on getChildren() to make this work and why can't I just make a "foin fetch" query, without "distinct"? If I remove "distinct" I get a multiplication. For each child of a parent, the entire parent is copied in the result set.
Is there a better way to do this? It just feels... a bit crappy.
In JPA you need to set distinct when you join a OneToMany, otherwise it will return duplicates.
This is required.
The JPA spec requires this, but it is an odd default, but relates to what happens in database joins.