Question

请帮我解决这个问题 - 我有抽象课和两个孩子：

@Table(name = "abstract_partner")
@Inheritance(strategy= InheritanceType.JOINED)
public abstract class AbstractPartner {

@Id
protected Long id;
protected String name;
protected String endpoint;
protected String code;
@Column(name = "api_key")
protected String apiKey;

public Long getId() {
    return id;
}

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

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getEndpoint() {
    return endpoint;
}

public void setEndpoint(String endpoint) {
    this.endpoint = endpoint;
}

public String getCode() {
    return code;
}

public void setCode(String code) {
    this.code = code;
}

@Override
public abstract boolean equals(Object o);

@Override
public int hashCode() {
    return Objects.hash(id);
}

public String getApiKey() {
    return apiKey;
}

public void setApiKey(String apiKey) {
    this.apiKey = apiKey;
}

}

CustomerPartnerGroupEntity

@Entity
@Table(name = "customer_partner_group")

public class CustomerPartnerGroupEntity extends AbstractPartner{

@Override
public boolean equals(Object o) {
    if (this == o) return true;
    if (!(o instanceof CustomerPartnerGroupEntity)) return false;
    CustomerPartnerGroupEntity that = (CustomerPartnerGroupEntity) o;
    return Objects.equals(id, that.id);
}
}

NetworkPartner

@Entity
@Table(name = "network_partners")

public class NetworkPartner extends AbstractPartner{

@OneToOne(mappedBy = "partner", fetch = FetchType.EAGER, cascade = CascadeType.ALL)
@JsonIgnore
private NetworkPartnerConfiguration configuration;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "payment_provider_id")
@JsonIgnore
private PaymentProviderEntity paymentProvider;


@Override
public boolean equals(Object o) {
    if (this == o) return true;
    if (!(o instanceof NetworkPartner)) return false;
    NetworkPartner that = (NetworkPartner) o;
    return Objects.equals(id, that.id);
}

public NetworkPartnerConfiguration getConfiguration() {
    return configuration;
}

public void setConfiguration(NetworkPartnerConfiguration configuration) {
    this.configuration = configuration;
}

public PaymentProviderEntity getPaymentProvider() {
    return paymentProvider;
}

public void setPaymentProvider(PaymentProviderEntity paymentProvider) {
    this.paymentProvider = paymentProvider;
}
}

尝试通过Hibernate实现继承与策略 - JOINED 但是当我使用这个策略时，我会收到异常：

Caused by: org.springframework.beans.factory.BeanCreationException: Error     creating bean with name 'entityManagerFactory' defined in class path resource [common-beans.xml]: Invocation of init method failed; nested exception is java.util.NoSuchElementException
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1572)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:960)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:749)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:125)
at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:60)
at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.delegateLoading(AbstractDelegatingSmartContextLoader.java:109)
at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.loadContext(AbstractDelegatingSmartContextLoader.java:261)
at org.springframework.test.context.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:68)
at org.springframework.test.context.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:86)
... 24 more
Caused by: java.util.NoSuchElementException
at java.util.ArrayList$Itr.next(ArrayList.java:854)
at org.hibernate.cfg.annotations.TableBinder.linkJoinColumnWithValueOverridingNameIfImplicit(TableBinder.java:487)
at org.hibernate.cfg.PkDrivenByDefaultMapsIdSecondPass.doSecondPass(PkDrivenByDefaultMapsIdSecondPass.java:54)
at org.hibernate.cfg.Configuration.processSecondPassesOfType(Configuration.java:1386)
at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1337)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1730)
at org.hibernate.ejb.EntityManagerFactoryImpl.<init>(EntityManagerFactoryImpl.java:94)
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:905)
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:890)
at org.springframework.orm.jpa.vendor.SpringHibernateEjbPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateEjbPersistenceProvider.java:51)
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:343)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1631)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1568)
... 39 more

奇怪的是 - 如果我选择其他策略（SINGLE TABLE或TABLE_PER_CLASS），则不会出现错误

Answer 1

仅将策略从JOINED更改为SINGLE_TABLE将无法解决此问题。您需要在父类中添加@DiscriminatorColumn，并且每个类父/子应该具有@DiscriminatorValue来区分单个表中的记录。

以下是示例代码：
的 Employee.java

import javax.persistence.Column; import javax.persistence.DiscriminatorColumn; import javax.persistence.DiscriminatorType; import javax.persistence.DiscriminatorValue; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Inheritance; import javax.persistence.InheritanceType; import javax.persistence.Table; @Entity @Table(name = "employee_tph") @Inheritance(strategy = InheritanceType.SINGLE_TABLE) @DiscriminatorColumn(name = "object_type", discriminatorType = DiscriminatorType.STRING) @DiscriminatorValue(value = "Employee") public class Employee { @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "Employee_Id") private long empId; @Column(name = "Employee_Name") private String name; public long getEmpId() { return empId; } public void setEmpId(long empId) { this.empId = empId; } public String getName() { return name; } public void setName(String name) { this.name = name; } }

Contract_Employee类：

import javax.persistence.Column; import javax.persistence.DiscriminatorValue; import javax.persistence.Entity; @Entity @DiscriminatorValue(value = "Contract_Employee") public class Contract_Employee extends Employee { @Column(name = "pay_per_hour") private float pay_per_hour; @Column(name = "contract_period") private String contract_period; public float getPay_per_hour() { return pay_per_hour; } public void setPay_per_hour(float pay_per_hour) { this.pay_per_hour = pay_per_hour; } public String getContract_period() { return contract_period; } public void setContract_period(String contract_period) { this.contract_period = contract_period; } }

Regular_Employee Class ：

import javax.persistence.Column; import javax.persistence.DiscriminatorValue; import javax.persistence.Entity; @Entity @DiscriminatorValue(value = "Regular_Employee") public class Regular_Employee extends Employee { @Column(name = "salary") private float salary; @Column(name = "bonus") private float bonus; public float getSalary() { return salary; } public void setSalary(float salary) { this.salary = salary; } public float getBonus() { return bonus; } public void setBonus(float bonus) { this.bonus = bonus; } }

主要课程功能：

public static void main(String[] args) { SessionFactory sessionFactory=HibernateUtil.getSessionAnnotationFactory(); Session session=sessionFactory.openSession(); Transaction tx=session.beginTransaction(); Employee e1=new Employee(); e1.setName("Rohit"); Regular_Employee r1=new Regular_Employee(); r1.setBonus(1000.50f); r1.setName("Peter"); r1.setSalary(45000.56f); Contract_Employee c1=new Contract_Employee(); c1.setName("Harry"); c1.setContract_period("4 yrs 5 months"); c1.setPay_per_hour(45.5f); session.persist(e1); session.persist(c1); session.persist(r1); tx.commit(); session.close(); System.out.println("success.."); }

Answer 2

我尝试运行

时出现错误

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { "classpath:common-beans.xml" })
@TransactionConfiguration(defaultRollback = true)
@Transactional
public class PartnerDAOTest {

private Partner partner;
private SystemUser user;

@Autowired
private PartnerDAO partnerDAO;
@Autowired
private SystemUserService systemUserService;
//
@Autowired
private SystemUserRoleService systemUserRoleService;

static {
    System.setProperty("envTarget", "local");
}


public PartnerDAOTest() {
}

@Before
public void testSave() {
    user = new SystemUser();
    user.setEmail("1@gmail.com");
    user.setPassword("11");
    //
    user.setRole(systemUserRoleService.findByName(SystemUserRole.Name.ROLE_ADMIN));

    this.systemUserService.persist(user);

    Assert.assertTrue(user.getId() > 0);

    partner = new Partner();
    partner.setEnabled(0);
    partner.setPkey(UUID.randomUUID().toString());
    partner.setApiKey(UUID.randomUUID().toString().substring(0, 32));

    Set<SystemUser> users = new HashSet<>();
    users.add(user);
    //partner.setSystemUsers(users);
    Set<Partner> partners = new HashSet<>();
    partners.add(partner);
    //user.setPartners(partners);

    this.partnerDAO.persist(partner);

    Assert.assertNotNull(partner);
    Assert.assertTrue(partner.getId() > 0);
}

@Test
public void testGetById() {
    Partner found = this.partnerDAO.get(partner.getId());

    Assert.assertNotNull(found);
    Assert.assertTrue(partner.getId() == found.getId());
}

@Test
public void testUpdate() {
    partner.setEnabled(1);
    this.partnerDAO.update(partner);

    Assert.assertEquals(partner.getEnabled(), 1);
}

@Test
public void testFindByIds() {
    List<Long> ids = new ArrayList<>();
    ids.add(partner.getId());

    Set<Partner> partners = this.partnerDAO.findByIds(ids);
    Assert.assertTrue(CollectionUtils.isNotEmpty(partners));
}

}

麻烦继承hibernate

2 个答案: