Spring Data JPA - 为三个表创建@Composite 键
Spring Data JPA - create @Composite key for the three tables
我从这里扩展我的问题：Define CompositeKey with three tables using JPA/Hibernate?。在此示例中，我希望创建 复合键 以创建 PRODUCT_ID、CATEGORY_ID、STOCK_ID.
的唯一组合
我开发了以下代码，但不确定如何将记录保存到数据库中。
Stock.java
@Entity
public class Stock implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "STOCK_ID", unique = true, nullable = false)
private Integer stockId;
@Column(name = "STOCK_CODE", unique = true, nullable = false, length = 10)
private String stockCode;
@Column(name = "STOCK_NAME", unique = true, nullable = false, length = 20)
private String stockName;
// Owner of the relationship
@OneToMany(fetch = FetchType.LAZY, mappedBy = "linkPk.stock", cascade = CascadeType.ALL)
private Set<StockCategoryProductLink> stockCategoryProductLinks = new HashSet<>(0);
public Stock() {
}
public Stock(Integer stockId, String stockCode, String stockName,
Set<StockCategoryProductLink> stockCategoryProductLinks) {
super();
this.stockId = stockId;
this.stockCode = stockCode;
this.stockName = stockName;
this.stockCategoryProductLinks = stockCategoryProductLinks;
}
public Integer getStockId() {
return stockId;
}
public void setStockId(Integer stockId) {
this.stockId = stockId;
}
public String getStockCode() {
return stockCode;
}
public void setStockCode(String stockCode) {
this.stockCode = stockCode;
}
public String getStockName() {
return stockName;
}
public void setStockName(String stockName) {
this.stockName = stockName;
}
public Set<StockCategoryProductLink> getStockCategoryProductLinks() {
return stockCategoryProductLinks;
}
public void setStockCategoryProductLinks(Set<StockCategoryProductLink> stockCategoryProductLinks) {
this.stockCategoryProductLinks = stockCategoryProductLinks;
}
}
Product.java
public class Product implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "PRODUCT_ID", unique = true, nullable = false)
private Integer productId;
@Column(name = "PRODUCT_NAME")
private String productName;
@Column(name = "PRODUCT_CODE", unique = true, nullable = false, length = 10)
private String productCode;
@OneToMany(mappedBy = "linkPk.product", cascade = { CascadeType.PERSIST, CascadeType.MERGE })
private List<StockCategoryProductLink> userDepartmentRoleLinks;
public Product(String productName, String productCode) {
this.productName = productName;
this.productCode = productCode;
}
public Integer getProductId() {
return productId;
}
public void setProductId(Integer productId) {
this.productId = productId;
}
public String getProductName() {
return productName;
}
public void setProductName(String productName) {
this.productName = productName;
}
public String getProductCode() {
return productCode;
}
public void setProductCode(String productCode) {
this.productCode = productCode;
}
public List<StockCategoryProductLink> getUserDepartmentRoleLinks() {
return userDepartmentRoleLinks;
}
public void setUserDepartmentRoleLinks(List<StockCategoryProductLink> userDepartmentRoleLinks) {
this.userDepartmentRoleLinks = userDepartmentRoleLinks;
}
}
Category.java
Entity
@Table(name = "category", catalog = "mkyongdb")
public class Category implements java.io.Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "CATEGORY_ID", unique = true, nullable = false)
private Integer categoryId;
@Column(name = "NAME", nullable = false, length = 10)
private String name;
@Column(name = "[DESC]", nullable = false)
private String desc;
@OneToMany(fetch = FetchType.LAZY, mappedBy = "linkPk.category")
private Set<StockCategoryProductLink> stockCategories = new HashSet<>(0);
public Category() {
}
public Category(String name, String desc) {
this.name = name;
this.desc = desc;
}
public Category(String name, String desc, Set<StockCategoryProductLink> stockCategories) {
this.name = name;
this.desc = desc;
this.stockCategories = stockCategories;
}
public Integer getCategoryId() {
return categoryId;
}
public void setCategoryId(Integer categoryId) {
this.categoryId = categoryId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDesc() {
return desc;
}
public void setDesc(String desc) {
this.desc = desc;
}
public Set<StockCategoryProductLink> getStockCategories() {
return stockCategories;
}
public void setStockCategories(Set<StockCategoryProductLink> stockCategories) {
this.stockCategories = stockCategories;
}
}
StockCategoryProductLink.java
@Embeddable
public class StockCategoryProductLink implements Serializable {
private static final long serialVersionUID = 1L;
@EmbeddedId
private StockCategoryProductLinkId linkPk = new StockCategoryProductLinkId();
@Transient
public Stock getStock() {
return getLinkPk().getStock();
}
@Transient
public Category getCategory() {
return getLinkPk().getCategory();
}
@Transient
public Product getProduct() {
return getLinkPk().getProduct();
}
public StockCategoryProductLinkId getLinkPk() {
return linkPk;
}
public void setLinkPk(StockCategoryProductLinkId linkPk) {
this.linkPk = linkPk;
}
}
StockCategoryProductLinkId.java
@Embeddable
public class StockCategoryProductLinkId {
@ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
@JoinColumn(name = "CATEGORY_ID")
private Category category;
@ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
@JoinColumn(name = "STOCK_ID")
private Stock stock;
@ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
@JoinColumn(name = "PRODUCT_ID")
private Product product;
public Category getCategory() {
return category;
}
public void setCategory(Category category) {
this.category = category;
}
public Stock getStock() {
return stock;
}
public void setStock(Stock stock) {
this.stock = stock;
}
public Product getProduct() {
return product;
}
public void setProduct(Product product) {
this.product = product;
}
}
ManyToManyApplication.java
@SpringBootApplication
public class ManyToManyApplication implements CommandLineRunner{
public static void main(String[] args) {
SpringApplication.run(ManyToManyApplication.class, args);
}
@Autowired
private CategoryRepository categoryRepository;
@Autowired
private StockRepository stockRepository;
@Autowired
private ProductRepository productRepository;
@Override
public void run(String... args) throws Exception {
saveDataFirstTime();
}
private void saveDataFirstTime() {
// Category
Category category1 = new Category("CONSUMER", "CONSUMER COMPANY");
categoryRepository.save(category1);
// Product
Product product = new Product("Product-1", "AB");
productRepository.save(product);
// Stock
Stock stock = new Stock();
stock.setStockCode("7052");
stock.setStockName("PADINI");
// StockCategoryProductLink
StockCategoryProductLink link = new StockCategoryProductLink();
link.getLinkPk().setCategory(category1);
link.getLinkPk().setProduct(product);
link.getLinkPk().setStock(stock);
stock.getStockCategoryProductLinks().add(link);
stockRepository.save(stock);
}
}
错误：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: Use of @OneToMany or @ManyToMany targeting an unmapped class: com.example.entity.Stock.stockCategoryProductLinks[com.example.entity.StockCategoryProductLink]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1778) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=17=](AbstractBeanFactory.java:320) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1105) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:742) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:389) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:311) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1213) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1202) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at com.example.ManyToManyApplication.main(ManyToManyApplication.java:20) [classes/:na]
Caused by: org.hibernate.AnnotationException: Use of @OneToMany or @ManyToMany targeting an unmapped class: com.example.entity.Stock.stockCategoryProductLinks[com.example.entity.StockCategoryProductLink]
at org.hibernate.cfg.annotations.CollectionBinder.bindManyToManySecondPass(CollectionBinder.java:1274) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:811) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.cfg.annotations.CollectionBinder.secondPass(CollectionBinder.java:736) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:54) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1696) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1664) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:287) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:904) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:935) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:57) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:390) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:377) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1837) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1774) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
... 15 common frames omitted
好吧，我知道你说的是什么，但我认为这不是你的意思。你说
Actually I've three tables, Stock, Category and Product. @ManyToMany relationship between Stock and Category, as well as @ManyToMany relationship between Category and Product.
抽象地思考这个问题会有所帮助。用陈法你说的是
但这可能不是您的意思。这是有问题的，因为每个 Stock 和 Product 关系都需要一个新的 Category 实体。因此，如果您有一个 ETF 类别，那么 BobsBestETFs 产品中的每只股票都会复制它，实际上是每个实例化关系。
您的意思可能更像是 Stock 和 Product 与 Category 属性的关系，就像这样。
这允许许多产品，每个产品都有很多股票，每个 product/stock 关系都有一个特定的类别属性。您将遇到的问题是您不希望 Category 成为属性，而是希望查找 table 类别，如下所示：
我想这就是您要找的。使用复合 ID 实现这应该相当简单，但您显示的示例似乎有些过时或不清楚。最好找到更好的例子。这就是我为最后一个模式建模的方式。
@Entity
public class Stock {
@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
}
@Entity
@Data
public class Product {
@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
}
@Entity
public class Category {
@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
}
@Entity
@Data
public class StockProduct {
@EmbeddedId
private StockProductPk id;
@ManyToOne
@MapsId("productId")
private Product product;
@ManyToOne
@MapsId("stockId")
private Stock stock;
@ManyToOne
private Category category;
}
@Embeddable
@Data
public class StockProductPk implements Serializable {
private static final long serialVersionUID = 1L;
private Long stockId;
private Long productId;
}
并作为使用它的示例：
private void create() {
Category catEtf = new Category();
categoryRepo.save(catEtf);
Stock s1 = new Stock();
stockRepo.save(s1);
Product bobEtfs = new Product();
productRepo.save(bobEtfs);
// create a relationship
StockProduct bs1 = new StockProduct();
bs1.setId(new StockProductPk());
bs1.setProduct(bobEtfs);
bs1.setStock(s1);
bs1.setCategory(catEtf);
stockProductRepo.save(bs1);
}
private void read() {
StockProduct sp1 = new StockProduct();
Product p1 = new Product();
p1.setId(1L);
sp1.setProduct(p1);
List<StockProduct> bobEtfs = stockProductRepo.findAll(Example.of(sp1, ExampleMatcher.matching()));
System.out.println(bobEtfs);
}
我从这里扩展我的问题：Define CompositeKey with three tables using JPA/Hibernate?。在此示例中，我希望创建 复合键 以创建 PRODUCT_ID、CATEGORY_ID、STOCK_ID.
的唯一组合我开发了以下代码，但不确定如何将记录保存到数据库中。
Stock.java
@Entity
public class Stock implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "STOCK_ID", unique = true, nullable = false)
private Integer stockId;
@Column(name = "STOCK_CODE", unique = true, nullable = false, length = 10)
private String stockCode;
@Column(name = "STOCK_NAME", unique = true, nullable = false, length = 20)
private String stockName;
// Owner of the relationship
@OneToMany(fetch = FetchType.LAZY, mappedBy = "linkPk.stock", cascade = CascadeType.ALL)
private Set<StockCategoryProductLink> stockCategoryProductLinks = new HashSet<>(0);
public Stock() {
}
public Stock(Integer stockId, String stockCode, String stockName,
Set<StockCategoryProductLink> stockCategoryProductLinks) {
super();
this.stockId = stockId;
this.stockCode = stockCode;
this.stockName = stockName;
this.stockCategoryProductLinks = stockCategoryProductLinks;
}
public Integer getStockId() {
return stockId;
}
public void setStockId(Integer stockId) {
this.stockId = stockId;
}
public String getStockCode() {
return stockCode;
}
public void setStockCode(String stockCode) {
this.stockCode = stockCode;
}
public String getStockName() {
return stockName;
}
public void setStockName(String stockName) {
this.stockName = stockName;
}
public Set<StockCategoryProductLink> getStockCategoryProductLinks() {
return stockCategoryProductLinks;
}
public void setStockCategoryProductLinks(Set<StockCategoryProductLink> stockCategoryProductLinks) {
this.stockCategoryProductLinks = stockCategoryProductLinks;
}
}
Product.java
public class Product implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "PRODUCT_ID", unique = true, nullable = false)
private Integer productId;
@Column(name = "PRODUCT_NAME")
private String productName;
@Column(name = "PRODUCT_CODE", unique = true, nullable = false, length = 10)
private String productCode;
@OneToMany(mappedBy = "linkPk.product", cascade = { CascadeType.PERSIST, CascadeType.MERGE })
private List<StockCategoryProductLink> userDepartmentRoleLinks;
public Product(String productName, String productCode) {
this.productName = productName;
this.productCode = productCode;
}
public Integer getProductId() {
return productId;
}
public void setProductId(Integer productId) {
this.productId = productId;
}
public String getProductName() {
return productName;
}
public void setProductName(String productName) {
this.productName = productName;
}
public String getProductCode() {
return productCode;
}
public void setProductCode(String productCode) {
this.productCode = productCode;
}
public List<StockCategoryProductLink> getUserDepartmentRoleLinks() {
return userDepartmentRoleLinks;
}
public void setUserDepartmentRoleLinks(List<StockCategoryProductLink> userDepartmentRoleLinks) {
this.userDepartmentRoleLinks = userDepartmentRoleLinks;
}
}
Category.java
Entity
@Table(name = "category", catalog = "mkyongdb")
public class Category implements java.io.Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "CATEGORY_ID", unique = true, nullable = false)
private Integer categoryId;
@Column(name = "NAME", nullable = false, length = 10)
private String name;
@Column(name = "[DESC]", nullable = false)
private String desc;
@OneToMany(fetch = FetchType.LAZY, mappedBy = "linkPk.category")
private Set<StockCategoryProductLink> stockCategories = new HashSet<>(0);
public Category() {
}
public Category(String name, String desc) {
this.name = name;
this.desc = desc;
}
public Category(String name, String desc, Set<StockCategoryProductLink> stockCategories) {
this.name = name;
this.desc = desc;
this.stockCategories = stockCategories;
}
public Integer getCategoryId() {
return categoryId;
}
public void setCategoryId(Integer categoryId) {
this.categoryId = categoryId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDesc() {
return desc;
}
public void setDesc(String desc) {
this.desc = desc;
}
public Set<StockCategoryProductLink> getStockCategories() {
return stockCategories;
}
public void setStockCategories(Set<StockCategoryProductLink> stockCategories) {
this.stockCategories = stockCategories;
}
}
StockCategoryProductLink.java
@Embeddable
public class StockCategoryProductLink implements Serializable {
private static final long serialVersionUID = 1L;
@EmbeddedId
private StockCategoryProductLinkId linkPk = new StockCategoryProductLinkId();
@Transient
public Stock getStock() {
return getLinkPk().getStock();
}
@Transient
public Category getCategory() {
return getLinkPk().getCategory();
}
@Transient
public Product getProduct() {
return getLinkPk().getProduct();
}
public StockCategoryProductLinkId getLinkPk() {
return linkPk;
}
public void setLinkPk(StockCategoryProductLinkId linkPk) {
this.linkPk = linkPk;
}
}
StockCategoryProductLinkId.java
@Embeddable
public class StockCategoryProductLinkId {
@ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
@JoinColumn(name = "CATEGORY_ID")
private Category category;
@ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
@JoinColumn(name = "STOCK_ID")
private Stock stock;
@ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
@JoinColumn(name = "PRODUCT_ID")
private Product product;
public Category getCategory() {
return category;
}
public void setCategory(Category category) {
this.category = category;
}
public Stock getStock() {
return stock;
}
public void setStock(Stock stock) {
this.stock = stock;
}
public Product getProduct() {
return product;
}
public void setProduct(Product product) {
this.product = product;
}
}
ManyToManyApplication.java
@SpringBootApplication
public class ManyToManyApplication implements CommandLineRunner{
public static void main(String[] args) {
SpringApplication.run(ManyToManyApplication.class, args);
}
@Autowired
private CategoryRepository categoryRepository;
@Autowired
private StockRepository stockRepository;
@Autowired
private ProductRepository productRepository;
@Override
public void run(String... args) throws Exception {
saveDataFirstTime();
}
private void saveDataFirstTime() {
// Category
Category category1 = new Category("CONSUMER", "CONSUMER COMPANY");
categoryRepository.save(category1);
// Product
Product product = new Product("Product-1", "AB");
productRepository.save(product);
// Stock
Stock stock = new Stock();
stock.setStockCode("7052");
stock.setStockName("PADINI");
// StockCategoryProductLink
StockCategoryProductLink link = new StockCategoryProductLink();
link.getLinkPk().setCategory(category1);
link.getLinkPk().setProduct(product);
link.getLinkPk().setStock(stock);
stock.getStockCategoryProductLinks().add(link);
stockRepository.save(stock);
}
}
错误：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: Use of @OneToMany or @ManyToMany targeting an unmapped class: com.example.entity.Stock.stockCategoryProductLinks[com.example.entity.StockCategoryProductLink]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1778) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=17=](AbstractBeanFactory.java:320) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1105) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:742) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:389) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:311) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1213) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1202) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at com.example.ManyToManyApplication.main(ManyToManyApplication.java:20) [classes/:na]
Caused by: org.hibernate.AnnotationException: Use of @OneToMany or @ManyToMany targeting an unmapped class: com.example.entity.Stock.stockCategoryProductLinks[com.example.entity.StockCategoryProductLink]
at org.hibernate.cfg.annotations.CollectionBinder.bindManyToManySecondPass(CollectionBinder.java:1274) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:811) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.cfg.annotations.CollectionBinder.secondPass(CollectionBinder.java:736) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:54) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1696) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1664) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:287) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:904) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:935) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:57) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:390) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:377) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1837) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1774) ~[spring-beans-5.1.8.RELEASE.jar:5.1.8.RELEASE]
... 15 common frames omitted
好吧，我知道你说的是什么，但我认为这不是你的意思。你说
Actually I've three tables, Stock, Category and Product.
@ManyToManyrelationship between Stock and Category, as well as@ManyToManyrelationship between Category and Product.
抽象地思考这个问题会有所帮助。用陈法你说的是
但这可能不是您的意思。这是有问题的，因为每个 Stock 和 Product 关系都需要一个新的 Category 实体。因此，如果您有一个 ETF 类别，那么 BobsBestETFs 产品中的每只股票都会复制它，实际上是每个实例化关系。
您的意思可能更像是 Stock 和 Product 与 Category 属性的关系，就像这样。
这允许许多产品，每个产品都有很多股票，每个 product/stock 关系都有一个特定的类别属性。您将遇到的问题是您不希望 Category 成为属性，而是希望查找 table 类别，如下所示：
我想这就是您要找的。使用复合 ID 实现这应该相当简单，但您显示的示例似乎有些过时或不清楚。最好找到更好的例子。这就是我为最后一个模式建模的方式。
@Entity
public class Stock {
@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
}
@Entity
@Data
public class Product {
@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
}
@Entity
public class Category {
@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
}
@Entity
@Data
public class StockProduct {
@EmbeddedId
private StockProductPk id;
@ManyToOne
@MapsId("productId")
private Product product;
@ManyToOne
@MapsId("stockId")
private Stock stock;
@ManyToOne
private Category category;
}
@Embeddable
@Data
public class StockProductPk implements Serializable {
private static final long serialVersionUID = 1L;
private Long stockId;
private Long productId;
}
并作为使用它的示例：
private void create() {
Category catEtf = new Category();
categoryRepo.save(catEtf);
Stock s1 = new Stock();
stockRepo.save(s1);
Product bobEtfs = new Product();
productRepo.save(bobEtfs);
// create a relationship
StockProduct bs1 = new StockProduct();
bs1.setId(new StockProductPk());
bs1.setProduct(bobEtfs);
bs1.setStock(s1);
bs1.setCategory(catEtf);
stockProductRepo.save(bs1);
}
private void read() {
StockProduct sp1 = new StockProduct();
Product p1 = new Product();
p1.setId(1L);
sp1.setProduct(p1);
List<StockProduct> bobEtfs = stockProductRepo.findAll(Example.of(sp1, ExampleMatcher.matching()));
System.out.println(bobEtfs);
}