Hibernate继承问题 [英] Trouble with hibernate inheritance

问题描述

请帮我解决这个问题 - 我有抽象类
和两个子元素：

  @Table（name =abstract_partner）
 @Inheritance（strategy = InheritanceType.JOINED）
 public abstract class AbstractPartner {
 
 @Id 
 protected Long id; 
保护字符串名称; 
保护字符串端点; 
保护字符串代码; 
 @Column（name =api_key）
保护字符串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扩展AbstractPartner {
 
 @Override 
 public boolean equals（Object o）{
 if（this == o）return true; 
 if（！（o instanceof CustomerPartnerGroupEntity））返回false; 
 CustomerPartnerGroupEntity that =（CustomerPartnerGroupEntity）o; 
返回Objects.equals（id，that.id）; 
 
 
 $ / code $ / pre 
 
 NetworkPartner 
 
 
  @Entity 
 @Table（name =network_partners）
 
 public class NetworkPartner extends AbstractPartner {
 
 @OneToOne（mappedBy =partner，fetch = FetchType.EAGER，cascade = CascadeType.ALL）
 @JsonIgnore 
专用NetworkPartnerConfiguration配置; 
 
 @ManyToOne（fetch = FetchType.LAZY）
 @JoinColumn（name =payment_provider_id）
 @JsonIgnore 
私人PaymentProviderEntity paymentProvider; 
 
 
 @Override 
 public boolean equals（Object o）{
 if（this == o）return true; 
 if（！（o instanceof NetworkPartner））返回false; 
 NetworkPartner that =（NetworkPartner）o; 
返回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; 
 
 
 $ / code> 
并尝试通过Hibernate实现继承策略 -  JOINED 
但是当我使用这个策略时，我收到了异常：
 原因：org.springframework.beans.factory.BeanCreationException ：在类路径资源[common-beans.xml]中定义名称为'entityManagerFactory'的bean时出错：init方法的调用失败;嵌套的异常是java.util.NoSuchElementException 
在org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean（AbstractAutowireCapableBeanFactory.java:1572）
在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.AbstractAppl icationContext.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）美元，org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.delegateLoading（AbstractDelegatingSmartContextLoader.java:109 b $ b）
在org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.loadContext（ AbstractDelegatingSmartContextLoader.java:261）
 at org.springframework.test.context.DefaultCacheAwareContextLoaderDelegate.loadContextInternal（DefaultCacheAwareContextLoaderDel 
 at org.springframework.test.context.DefaultCacheAwareContextLoaderDelegate.loadContext（DefaultCacheAwareContextLoaderDelegate.java:86）
 ... 24 more 
导致：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）
在org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory（Ejb3Configuration.java:905）
在org.hibernate.ejb.Ejb3C onfiguration.buildEntityManagerFactory（Ejb3Configuration.java:890）
 at org.springframework.orm.jpa.vendor.SpringHibernateEjbPersistenceProvider.createContainerEntityManagerFactory（SpringHibernateEjbPersistenceProvider.java:51）
位于org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean。 createNativeEntityManagerFactory（LocalContainerEntityManagerFactoryBean.java:343）
在org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet（AbstractEntityManagerFactoryBean.java:318）
在org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods（ AbstractAutowireCapableBeanFactory.java:1631）
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean（AbstractAutowireCapableBeanFactory.java:1568）
 ... 39 more 
  
奇怪的事情 - 如果我选择另一个策略（SINGLE TABLE或TABLE_PER_CLASS）错误不会出现
 
解决方案
仅通过将策略从JOINED更改为SINGLE_TABLE将无法解决此问题。您需要在父类中添加@DiscriminatorColumn，并且每个父类/子类都应该有@DiscriminatorValue来区分单个表中的记录。 
 
 
 
以下是一个示例代码：
 
  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）
私人字符串名称; 
 
 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 class ： 
 
 
  import javax.persistence.Column; 
 import javax.persistence.DiscriminatorValue; 
 import javax.persistence.Entity; 
 $ b $ @Entity 
 @DiscriminatorValue（value =Contract_Employee）
 public class Contract_Employee extends Employee {
 @Column（name =pay_per_hour）
私人浮动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; 
 
 
 $ b code 
 $ b Regular_Employee Class  strong>： 
 
 
  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）
私人流动薪资; 
 
 @Column（name =bonus）
私人浮动奖金; 
 
 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; 
 
 
 
 
 $ b主类函数 
 $ b $> / strong>：
 
 pre $  public static void main（String [] args）{
 SessionFactory sessionFactory = HibernateUtil.getSessionAnnotationFactory ）; 
 Session session = sessionFactory.openSession（）; 
 
 Transaction tx = session.beginTransaction（）; 
 
员工e1 =新员工（）; 
 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年5个月）; 
 c1.setPay_per_hour（45.5f）; 
 
 session.persist（e1）; 
 session.persist（c1）; 
 session.persist（r1）; 
 
 tx.commit（）; 
 session.close（）; 
 System.out.println（success ..）; 
} 
  
 
please help me with such issue - i have abstract class 
and two child:
@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;
}
}
and try to realise inheritance via Hibernate with strategy - JOINED
but when i use this strategy i receive exception:
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
strange thing - if i choose another strategy(SINGLE TABLE or TABLE_PER_CLASS) error don't appear
解决方案
Just by changing the strategy from JOINED to SINGLE_TABLE will not resolve this issue. You need to add @DiscriminatorColumn in parent class and each class parent/child should have @DiscriminatorValue to distinguish the records in single table.  

Below is an example code:

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 class:
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;
}

}
Main class function:
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..");
}


                        
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