JPA @OneToMany & @ManyToOne null

Question

我对ManyToOne关系有问题。

这些是我的实体：

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import javax.persistence.*;
import java.io.Serializable;
import java.time.ZonedDateTime;
import java.util.HashSet;
import java.util.Set;
import java.util.Objects;
/**
* A Product.
*/
@Entity
@Table(name = "product")
public class Product implements Serializable {

private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@ManyToOne
@JsonIgnoreProperties("")
private Supplier supplier;
@ManyToOne
@JsonIgnoreProperties("")
private Tax tax;
@OneToMany(mappedBy = "product")
private Set<Combination> combinations = new HashSet<>();
@OneToMany(mappedBy = "product")
private Set<ProductImages> images = new HashSet<>();
@OneToMany(mappedBy = "product")
private Set<ProductTranslate> translates = new HashSet<>();
@ManyToMany(mappedBy = "productIds")
@JsonIgnore
private Set<Category> categoryIds = new HashSet<>();

public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}

public Supplier getSupplier() {
return supplier;
}
public Product supplier(Supplier supplier) {
this.supplier = supplier;
return this;
}
public void setSupplier(Supplier supplier) {
this.supplier = supplier;
}
public Tax getTax() {
return tax;
}
public Product tax(Tax tax) {
this.tax = tax;
return this;
}
public void setTax(Tax tax) {
this.tax = tax;
}
public Set<Combination> getCombinations() {
return combinations;
}
public Product combinations(Set<Combination> combinations) {
this.combinations = combinations;
return this;
}
public Product addCombinations(Combination combination) {
this.combinations.add(combination);
combination.setProduct(this);
return this;
}
public Product removeCombinations(Combination combination) {
this.combinations.remove(combination);
combination.setProduct(null);
return this;
}
public void setCombinations(Set<Combination> combinations) {
this.combinations = combinations;
}
public Set<ProductImages> getImages() {
return images;
}
public Product images(Set<ProductImages> productImages) {
this.images = productImages;
return this;
}
public Product addImages(ProductImages productImages) {
this.images.add(productImages);
productImages.setProduct(this);
return this;
}
public Product removeImages(ProductImages productImages) {
this.images.remove(productImages);
productImages.setProduct(null);
return this;
}
public void setImages(Set<ProductImages> productImages) {
this.images = productImages;
}
public Set<ProductTranslate> getTranslates() {
return translates;
}
public Product translates(Set<ProductTranslate> productTranslates) {
this.translates = productTranslates;
return this;
}
public Product addTranslates(ProductTranslate productTranslate) {
this.translates.add(productTranslate);
productTranslate.setProduct(this);
return this;
}
public Product removeTranslates(ProductTranslate productTranslate) {
this.translates.remove(productTranslate);
productTranslate.setProduct(null);
return this;
}
public void setTranslates(Set<ProductTranslate> productTranslates) {
this.translates = productTranslates;
}
public Set<Category> getCategoryIds() {
return categoryIds;
}
public Product categoryIds(Set<Category> categories) {
this.categoryIds = categories;
return this;
}
public Product addCategoryId(Category category) {
this.categoryIds.add(category);
category.getProductIds().add(this);
return this;
}
public Product removeCategoryId(Category category) {
this.categoryIds.remove(category);
category.getProductIds().remove(this);
return this;
}
public void setCategoryIds(Set<Category> categories) {
this.categoryIds = categories;
}
}

和：

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import javax.persistence.*;
import java.io.Serializable;
import java.util.Objects;
/**
* A ProductImages.
*/
@Entity
@Table(name = "product_images")
public class ProductImages implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@Column(name = "is_default")
private Boolean isDefault;
@Column(name = "url")
private String url;
@ManyToOne
@JsonIgnoreProperties("images")
private Product product;

public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public Boolean isIsDefault() {
return isDefault;
}
public ProductImages isDefault(Boolean isDefault) {
this.isDefault = isDefault;
return this;
}
public void setIsDefault(Boolean isDefault) {
this.isDefault = isDefault;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public ProductImages url(String url) {
this.url = url;
return this;
}
public Product getProduct() {
return product;
}
public ProductImages product(Product product) {
this.product = product;
return this;
}
public void setProduct(Product product) {
this.product = product;
}
}

现在，当我尝试发送获取所有产品的请求时，我希望也能获取所有图像。但我变空了。

这是我的存储库：

@Repository
public interface ProductRepository extends JpaRepository<Product, Long>, JpaSpecificationExecutor<Product> {
@Query(value = "SELECT p FROM " +
"Product p WHERE p.insertDate > ?1 ORDER BY p.insertDate DESC")
Page<Product> findFeatured(ZonedDateTime inserDate, Pageable pageable);
}

在我的数据库表中有记录：

ID, price, stock, manifacture_id, supplier_id, tax_id, weight, weight_unit, width, height, depth, lenght_unit, status, insert_date, priority
'1', '12.10', '10', '1', NULL, NULL, '2', 'KG', '22.1', '12.4', '3', 'CM', 'ACTIVE', '2018-08-01 00:00:00', '0'

产品图片表：

ID, product_id, is_default, url
1, 1, 0, dfsdfsdfs
2, 1, 0, jghjjggj

我什么都做了，但找不到解决方案。

当我根据请求检查sql时：

Hibernate: select product0_.id as id1_10_0_, product0_.depth as depth2_10_0_, product0_.height as height3_10_0_, product0_.insert_date as insert_d4_10_0_, product0_.lenght_unit as lenght_u5_10_0_, product0_.manifacture_id as manifact6_10_0_, product0_.price as price7_10_0_, product0_.priority as priority8_10_0_, product0_.status as status9_10_0_, product0_.stock as stock10_10_0_, product0_.supplier_id as supplie14_10_0_, product0_.tax_id as tax_id15_10_0_, product0_.weight as weight11_10_0_, product0_.weight_unit as weight_12_10_0_, product0_.width as width13_10_0_, supplier1_.id as id1_13_1_, supplier1_.about as about2_13_1_, supplier1_.birthdate as birthdat3_13_1_, supplier1_.email as email4_13_1_, supplier1_.name as name5_13_1_, supplier1_.overall_raiting as overall_6_13_1_, supplier1_.password as password7_13_1_, supplier1_.status as status8_13_1_, supplier1_.surname as surname9_13_1_, tax2_.id as id1_15_2_, tax2_.is_active as is_activ2_15_2_, tax2_.name as name3_15_2_, tax2_.percentage as percenta4_15_2_ from product product0_ left outer join supplier supplier1_ on product0_.supplier_id=supplier1_.id left outer join tax tax2_ on product0_.tax_id=tax2_.id where product0_.id=?

结果如下：

{
"id": 1,
"price": 12.1,
"stock": 10,
"manifactureId": 1,
"weight": 2,
"weightUnit": "KG",
"width": 22.1,
"height": 12.4,
"depth": 3,
"lenghtUnit": "CM",
"status": "ACTIVE",
"insertDate": "2018-08-01T00:00:00+04:00",
"priority": 0,
"supplier": null,
"tax": null,
"combinations": null,
"images": null,
"translates": null
}

有人知道吗？

Answer 1

@OneToMany中fetchType的默认值为FetchType.LAZY。

使其取CCD_ 4。

@OneToMany(fetch = FetchType.EAGER, mappedBy = "product")

您将在用于拾取图像的查询中找到一个join。

@一对多

Answer 2

// If your result need images,you can call getImages()
// Product your get
product.getImages()

然后将执行获取图像Sql。

如果您的结果不需要图像，则不需要调用getImages()

如果使用fetch = FetchType.EAGER，您的结果总是在产品中有图像。