我正在使用 Spring Data JPA 開發 Spring Boot 應用程式，并且在實作 Hibernate 映射時發現了以下問題。
基本上我首先在我的資料庫上創建表，然后我創建了映射這些表的物體類（在我的專案中，資料庫表不是從物體類自動生成的）。
我有這兩個資料庫表：
portal_user：這是包含代表門戶用戶的記錄的主表。
CREATE TABLE IF NOT EXISTS public.portal_user ( id bigint NOT NULL GENERATED ALWAYS AS IDENTITY ( INCREMENT 1 START 1 MINVALUE 1 MAXVALUE 9223372036854775807 CACHE 1 ), first_name character varying(50) COLLATE pg_catalog."default" NOT NULL, middle_name character varying(50) COLLATE pg_catalog."default", surname character varying(50) COLLATE pg_catalog."default" NOT NULL, sex "char" NOT NULL, birthdate date NOT NULL, tex_code character varying(50) COLLATE pg_catalog."default" NOT NULL, e_mail character varying(50) COLLATE pg_catalog."default" NOT NULL, contact_number character varying(50) COLLATE pg_catalog."default" NOT NULL, created_at date NOT NULL, CONSTRAINT user_pkey PRIMARY KEY (id) )address：它包含表示以前用戶地址的記錄。每個用戶可以有一個或多個地址。
CREATE TABLE IF NOT EXISTS public.address ( id bigint NOT NULL GENERATED ALWAYS AS IDENTITY ( INCREMENT 1 START 1 MINVALUE 1 MAXVALUE 9223372036854775807 CACHE 1 ), country character varying(50) COLLATE pg_catalog."default" NOT NULL, province character varying(50) COLLATE pg_catalog."default" NOT NULL, zip_code character varying(5) COLLATE pg_catalog."default" NOT NULL, street character varying(250) COLLATE pg_catalog."default" NOT NULL, notes character varying(250) COLLATE pg_catalog."default", fk_user_id bigint NOT NULL, CONSTRAINT address_pkey PRIMARY KEY (id), CONSTRAINT fk_user_id FOREIGN KEY (fk_user_id) REFERENCES public.portal_user (id) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION NOT VALID )
正如你可以看到每個用戶可以有一個或多個這樣不會忽略的關系portal_user和地址是一對多的（因為一個用戶可以有多個不會忽略）。為了實作這種行為，地址包含代表特定portal_user記錄的 ID的fk_user_id欄位。
好的，然后我嘗試使用 Hibernate 映射這兩個表及其關系。
首先我創建了User物體類：
@Entity
@Table(name = "portal_user")
@Data
public class User implements Serializable {
private static final long serialVersionUID = 5062673109048808267L;
@Id
@Column(name = "id")
@GeneratedValue(strategy=GenerationType.IDENTITY)
private int id;
@Column(name = "first_name")
private String firstName;
@Column(name = "middle_name")
private String middleName;
@Column(name = "surname")
private String surname;
@Column(name = "sex")
private char sex;
@Column(name = "birthdate")
private Date birthdate;
@Column(name = "tex_code")
private String taxCode;
@Column(name = "e_mail")
private String eMail;
@Column(name = "contact_number")
private String contactNumber;
@Temporal(TemporalType.DATE)
@Column(name = "created_at")
private Date createdAt;
@OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "user", orphanRemoval = true)
@JsonManagedReference
private Set<Address> addressesList = new HashSet<>();
public User(String firstName, String middleName, String surname, char sex, Date birthdate, String taxCode,
String eMail, String contactNumber, Date createdAt) {
super();
this.firstName = firstName;
this.middleName = middleName;
this.surname = surname;
this.sex = sex;
this.birthdate = birthdate;
this.taxCode = taxCode;
this.eMail = eMail;
this.contactNumber = contactNumber;
this.createdAt = createdAt;
}
}
如您所見，此類包含定義到portal_user資料庫表和此OneToMany關系中的所有欄位。基本上它說一個用戶與多個地址有關：
@OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "user", orphanRemoval = true)
@JsonManagedReference
private Set<Address> addressesList = new HashSet<>();
Then I created the Address entity class mapping my DB address table, this one:
@Entity
@Table(name = "address")
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Address implements Serializable {
private static final long serialVersionUID = 6956974379644960088L;
@Id
@Column(name = "id")
@GeneratedValue(strategy=GenerationType.IDENTITY)
private int id;
@Column(name = "country")
private String country;
@Column(name = "province")
private String province;
@Column(name = "zip_code")
private String zipCode;
@Column(name = "street")
private String street;
@Column(name = "notes")
private String notes;
//@Column(name = "fk_user_id")
//private int fkUserId;
@ManyToOne
@EqualsAndHashCode.Exclude // Needed by Lombock in "Many To One" relathionship to avoid error
@JoinColumn(name = "id", referencedColumnName = "id")
@JsonBackReference
private User user;
public Address(String country, String province, String zipCode, String street, String notes, User user) {
super();
this.country = country;
this.province = province;
this.zipCode = zipCode;
this.street = street;
this.notes = notes;
this.user = user;
}
}
As usual it contains the mapping for the address database table and also contains the ManyToOne relationship linking this class to the previous User class:
@ManyToOne
@EqualsAndHashCode.Exclude // Needed by Lombock in "Many To One" relathionship to avoid error
@JoinColumn(name = "id", referencedColumnName = "id")
@JsonBackReference
private User user;
Basically it says that multiple instance of Address are linked to a single specific instance of User.
For the sake of completeness only this is my repository interface (at the moment it is empty because I am only testing the save() method provided by JpaRepository):
public interface UsersRepository extends JpaRepository<User, Integer> {
}
Finnally I created this unit test class in order to test the insertion of a new user with the related addresses:
@SpringBootTest()
@ContextConfiguration(classes = GetUserWsApplication.class)
@TestMethodOrder(OrderAnnotation.class)
public class UserRepositoryTest {
@Autowired
private UsersRepository userRepository;
@Test
@Order(1)
public void testInsertUser() {
User user = new User("Mario", null, "Rossi", 'M', new Date(), "XXX", "[email protected]", "329123456", new Date());
userRepository.save(user);
Set<Address> addressesList = new HashSet<>();
addressesList.add(new Address("Italy", "RM", "00100", "Via XXX 123", "near YYY", user));
assertTrue(true);
}
}
問題是運行此測驗方法時，我在堆疊跟蹤中收到以下錯誤訊息：
Caused by: javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.MappingException: Repeated column in mapping for entity: com.easydefi.users.entity.Address column: id (should be mapped with insert="false" update="false")
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:421) ~[spring-orm-5.3.12.jar:5.3.12]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:396) ~[spring-orm-5.3.12.jar:5.3.12]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.3.12.jar:5.3.12]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1863) ~[spring-beans-5.3.12.jar:5.3.12]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1800) ~[spring-beans-5.3.12.jar:5.3.12]
... 84 common frames omitted
Caused by: org.hibernate.MappingException: Repeated column in mapping for entity: com.easydefi.users.entity.Address column: id (should be mapped with insert="false" update="false")
at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:862) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
at org.hibernate.mapping.PersistentClass.checkPropertyColumnDuplication(PersistentClass.java:880) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:902) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:634) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
at org.hibernate.mapping.RootClass.validate(RootClass.java:267) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
at org.hibernate.boot.internal.MetadataImpl.validate(MetadataImpl.java:354) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:298) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:468) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1259) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) ~[spring-orm-5.3.12.jar:5.3.12]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.3.12.jar:5.3.12]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:409) ~[spring-orm-5.3.12.jar:5.3.12]
... 88 common frames omitted
為什么會出現這個錯誤？我錯過了什么？我該如何嘗試解決此錯誤？
uj5u.com熱心網友回復：
這是你的雙重映射
@ManyToOne
@EqualsAndHashCode.Exclude // Needed by Lombock in "Many To One" relathionship to avoid error
@JoinColumn(name = "id", referencedColumnName = "id")
private User user;
應該：
@ManyToOne
@EqualsAndHashCode.Exclude // Needed by Lombock in "Many To One" relathionship to avoid error
@JoinColumn(name = "fk_user_id", referencedColumnName = "id")
private User user;
您正在映射id兩次（第一次出現是@Id列名），外鍵列應該fk_user_id根據您的 DDL。
uj5u.com熱心網友回復：
您似乎在 Address 中映射了同一列兩次
@EqualsAndHashCode.Exclude // Needed by Lombock in "Many To One" relathionship to avoid error
@JoinColumn(name = "id", referencedColumnName = "id")
@JsonBackReference
private User user;
和
@Id
@Column(name = "id")
@GeneratedValue(strategy=GenerationType.IDENTITY)
private int id;
您可能想在第一個中說 user_id 但不能確定，因為我認為您粘貼了相同的 SQL 以創建表兩次，而不是地址一個。
編輯：嘗試在地址中的用戶用戶映射中使用 user_id 而不是 id ，錯誤應該消失。
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