I want to implement /search rest method that will filter my Product object for the given parameters and return me a pageable set of products that are filtered.
I was reading about Specification interface and Criteria API but i am having difficulties in implementing the solution.
Product entity:
#Entity
public class Product implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long productId;
#NotEmpty(message = "The product name must not be null.")
private String productName;
private String productDescription;
#Min(value = 0, message = "The product price must no be less then zero.")
private double productPrice;
#Min(value = 0, message = "The product unit must not be less than zero.")
private int unitInStock;
#ManyToMany
#JoinTable(name = "category_product", joinColumns = #JoinColumn(name = "product_id"), inverseJoinColumns = #JoinColumn(name = "category_id"))
private Set<Category> categories = new HashSet<>();
As i want the user to be able to search by category name also,bedsides a price range and unitInStock which is separate entity and it is linked with #ManyToMany relationship ,i want to have a method that would look something like:
#GetMapping("/search")
public ResponseEntity<Set<Product>> advancedSearch(#RequestParam(name="category") String categoryName,
#RequestParam(name="price") double price,
#RequestParam(name="unitInStock") int unitInStock ){
}
Category entity:
#Entity
public class Category implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long categoryId;
#NotEmpty(message = "Can not be null")
private String CategoryName;
#ManyToMany(mappedBy = "categories")
#JsonBackReference
private Set<Product> products = new HashSet<>();
Create spring repository with method with JPQL query:
#Query("select p from Product p left join p.categories c where c.CategoryName like ?1 and p.productPrice=?2 and p.unitInStock=?3")
List<Product> search(String categoryName, double price, int unitInStock)
Related
I am Using Spring Boot on Java to create user's order on his checkout. A new Orders object is created which has a Linked Set of Items. Those items are user's cart contents.
Order is created, but its set of Items is null. The set size is 0. I checked that in JUnit tests. Can you help me to find out what is wrong? Maybe I have defined entities incorrectly? Have a look at the picture of the database:
And check the entities, Orders:
#Entity
public class Orders {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#NotEmpty
#DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
private LocalDateTime submitedAt;
#NotEmpty
private String orderName;
#NotEmpty
#Column(name="`User`")
private String username;
#Enumerated(EnumType.STRING)
#Column
private OrderStatus status;
#OneToMany(mappedBy = "orders", cascade = { CascadeType.ALL}, fetch = FetchType.LAZY)
private Set<Item> items;
Item:
#Entity
public class Item {
#Id
private Integer id;
#Column(name="`NAME`")
private String dishName;
#Column(name = "`DESCRIPTION`", length = 2000)
private String dishDescription;
#Column(name = "`QUANTITY`")
private Integer quantityInCart;
#Column(name = "`USER`")
private String username;
#ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE, CascadeType.DETACH, CascadeType.REFRESH })
#JoinColumn(name = "ORDERS_ID")
private Orders orders;
How to do entities relation correctly? Should it be one direction or bi-directional relationship?
What are differences of these relations? And what kind of relationship I should use? Why?
I was doing JUnit tests for the Orders service methods. It turns out that it can create orders. And Order items from user's cart.
But when it is time to show order (GetMapping) then it returns Orders entity with empty items set.
I think it happens because JPA cannot find foreign key of items for its designated order. It is null.
Why is it null?
And this is the service method that creates such order by user request:
#Transactional
public ResponseEntity<String> createOrder (String username) {
User user = userService.findByUsername(username);
List<CartItem> items = cartRepo.findByUser(user);
if(items.size() > 0) {
Orders newOrder = new Orders();
Set<Item> orderItems = new LinkedHashSet<>();
for(CartItem item : items) {
// new Item(Integer id, String dishName, String dishDescription, Integer quantityInCart, String username)
Item orderItem = new Item(item.getId(), item.getDish().getName(),
item.getDish().getDescription(), item.getQuantity(), item.getUser().getUsername());
orderItems.add(orderItem);
}
newOrder.setItems(orderItems);
newOrder.setOrderName(user.getUsername()+"'s order");
newOrder.setStatus(OrderStatus.SUBMIT);
newOrder.setSubmitedAt();
newOrder.setUsername(username);
orderDao.save(newOrder);
cartService.removeAllUserProducts(username);
LOG.info("[{}]: A new order is created successfully.", username);
return new ResponseEntity<String>("A new order is created successfully.", HttpStatus.CREATED);
}
//...
}
I tried to do one direction relationship for other entities and it really created foreign keys on joined column fields. But I want to find out why my bidirectional way of joining is wrong. Maybe someone who really knows can explain.
The Order class should be like this:
#Entity
public class Orders {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#NotEmpty
#DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
private LocalDateTime submitedAt;
#NotEmpty
private String orderName;
#NotEmpty
#Column(name="`User`")
private String username;
#Enumerated(EnumType.STRING)
#Column
private OrderStatus status;
#OneToMany(cascade = { CascadeType.ALL}, fetch = FetchType.LAZY, orphanRemoval = true)
#JoinColumn(name="ORDERS_ID")
private Set<Item> items;
And Item class without Orders class and its ManyToOne relationship.
Now relationship is unidirectional. Item entity has foreign keys column name ORDERS_ID that has id's of Orders for which Items belong.
I've got 2 classes: Device and Category. 1 Device can have 1 assigned category, but 1 category can have assigned many different devices.
#Entity
#Data
#Table(name = "devices")
public class Device implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String description;
#Column(name="amount_of_items")
private Integer amountOfItems;
private BigDecimal price;
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "category_id")
private Category category;
public Device(String name, String description, Integer amountOfItems, BigDecimal price, Category category){
this.name = name;
this.description = description;
this.amountOfItems = amountOfItems;
this.price = price;
this.category = category;
}
public Device() {}
}
#Entity
#Data
#Table(name = "categories")
public class Category implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String description;
#OneToMany(mappedBy = "category", fetch = FetchType.EAGER)
private List<Device> devices = new ArrayList<>();
public Category(String name, String description){
this.name = name;
this.description = description;
}
public Category() { }
}
Can I get the actual list of devices for one Category? The below code returns me a null list of devices:
Category category = new Category("Urzadzenia AGD", "tylko dla klientow premium");
categoryRepository.save(category);
Device device = new Device("pralka", "samoobslugowa", 50, new BigDecimal("220"),
category);
deviceRepository.save(device);
System.out.println(category.getDevies()) ---> returns NULL
Can I do it by calling a getter like above?
save method already return value after save in Database you can use this
Category category = new Category("Urzadzenia AGD", "tylko dla klientow premium");
category= categoryRepository.save(category);
Device device = new Device("pralka", "samoobslugowa", 50, new BigDecimal("220"),
category);
deviceRepository.save(device);
System.out.println(category.getDevies())
and you must be make setter and getter method in your class
after this you have problem stackover flow exciption becouse the all device called category and categore call Devices
you can used #JsonIgnore annotation
Like this :
#OneToMany(mappedBy = "category", fetch = FetchType.EAGER)
#JsonIgnore
private List<Device> devices = new ArrayList<>();
I have 2 tables:
#Entity
#Table
public class ProductEntity extends AbstractEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long productId;
#OneToMany(mappedBy = "product", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.LAZY)
private Set<ProductItemEntity> productItems;
}
#Entity
#Table
public class ProductItemEntity extends AbstractEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long itemId;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "PRODUCT_ID", nullable = false)
private ProductEntity product;
#Column(name="PRODUCT_RATE") // Unique
private Integer productRate;
}
I am trying to run a test where I am querying by productId and productRate, which is as follow:
#Query("SELECT p FROM ProductEntity p JOIN FETCH p.productItems pi WHERE p.productId = :productId AND pi.productRate = :rate ")
ProductEntity findByProductAndRate(#Param("productId") Long productId, #Param("rate") Integer rate);
I save a product and product item first. Then execute above method to get the product with product item. But I get null result.
Don't know if I am missing something. Any help would be appreciated.
Spring Boot
H2 (#DataJpaTest)
I am trying to make webservice for food order management . I have a Entities Product and Restaurant and I am struggling to make Order Entity .
#Entity
public class Product {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#ManyToOne
#JoinColumn(name = "restaurant_id", referencedColumnName = "id", insertable=false, updatable=false)
#JsonBackReference
private Restaurant restaurant;
private int restaurant_id;
private String name;
private float price;
}
#Entity
public class Restaurant {
#Id
#GeneratedValue
private int id;
#NotNull
private String name;
private String city;
private String phone;
#OneToMany(fetch = FetchType.LAZY, mappedBy = "restaurant", cascade = CascadeType.ALL)
#JsonManagedReference
private List<Product> menu;
}
I want the Order entity to have a List. If i keep an attribute OrderId in Product , to Join tables Product and Order, will that be a good idea? Is there any better way to do it?
PS: I don't want to keep order Id with Product because i think Product should not be aware of it
Yes, that's a fine idea.
You can use List in Order entity and join them by having id of order in product.
it's kinda hard to tell what you really want, but this site (under headline relationships) has description of best practices for likely to all of your use cases!
https://vladmihalcea.com/tutorials/hibernate/
Cheers!
I have 2 tables 'orders' and 'orderlines' and used bidirectional OneToMany mapping.When i save the order, record is successfully inserted into table 'orders'.But my 'orderlines' table is empty.No record is inserted.
This is the save operation code in Controller.
#RequestMapping(value = "ordersuccess", method = RequestMethod.POST)
public String processOrder(#ModelAttribute("order") Order order,
#ModelAttribute("cart") Cart cart,
BindingResult result) {
if (!result.hasErrors()) {
Set<OrderLine> orderLines = new HashSet<OrderLine>();
for(CartLine c : cart.getCartLines()) {
OrderLine line = new OrderLine();
line.setOrder(order);
line.setProduct(c.getProduct());
line.setProductPrice(c.getProduct().getPrice());
line.setTotalPrice(c.getPrice());
orderLines.add(line);
order.setOrderLines(orderLines);
}
orderService.save(order);
orderLineService.save(orderLine);
}
return "ordersuccess";
}
Can someone point me what wrong i am doing.
EDIT:
OrderLine.java
public class OrderLine {
#Id
#GeneratedValue
#Column(name="orderline_id")
private int orderline_id;
#ManyToOne
#JoinColumn(name = "order_id")
private Order order;
#ManyToOne(targetEntity = Product.class,
cascade = CascadeType.ALL,
fetch = FetchType.LAZY)
#JoinTable(
name="products",
joinColumns=#JoinColumn(name="product_id")
)
private Product product;
)
Order.java
public class Order {
#Id
#GeneratedValue
#Column(name="id")
private int id;
#OneToMany(mappedBy = "order")
private Set<OrderLine> orderLines;
//getter/setter
The orderLines object is created:
Set<OrderLine> orderLines = new HashSet<OrderLine>();
You then add lines to it:
orderLines.add(line);
But it never attributed to an order or sent to the service layer.
Also the OrderLine.product mapping should be like this
public class OrderLine {
#Id
#GeneratedValue
#Column(name="orderline_id")
private int orderline_id;
#ManyToOne
#JoinColumn(name = "order_id")
private Order order;
#ManyToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "product_id")
private Product product;
}
and Order.orderLines should have a cascade:
public class Order {
#Id
#GeneratedValue
#Column(name="id")
private int id;
#OneToMany(mappedBy = "order", cascade = CascadeType.ALL)
private Set<OrderLine> orderLines;
}
You then need to save the orderLines:
order.setOrderLines(orderLines);
and save the order:
orderService.save(order);
When order is saved it will cascade the orderlines and the associated product too.
If you have bidirectional associations don't forget to set both sides.