Question

我有三节课。 Person，vehicle和association类来关联此人和车辆

人

package entity;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.OneToMany;
import javax.persistence.Table;

import org.hibernate.annotations.LazyCollection;
import org.hibernate.annotations.LazyCollectionOption;

@Entity
@Table(name ="PERSON")
public class Person {
@EmbeddedId
private PKperson pkPerson;

@LazyCollection(LazyCollectionOption.FALSE)
@OneToMany(cascade=CascadeType.ALL,mappedBy="person")
private Set<PersonVehAssnVO> personVehAssnVOSet=new HashSet<PersonVehAssnVO>();

//getters & setters
}

PKperson

import java.io.Serializable;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Embeddable;

@Embeddable
public class PKperson implements Serializable {

@Column(name="NAME", nullable=false)
private String name;

@Column(name="DOB_DT", nullable=false)
private Date dobDt;
}

车辆

package entity;
import java.util.Date;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.OneToMany;
import javax.persistence.Id;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;

import org.hibernate.annotations.LazyCollection;
import org.hibernate.annotations.LazyCollectionOption;

@Entity
@Table(name ="VEHICLE")
public class Vehicle {
@Id
@Column(name="VEHICLE_ID",unique=true, nullable=false)  
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "seq_name")
@SequenceGenerator(allocationSize = 1, name = "seq_name", sequenceName = "SEQ_VEHICLE_ID")
private Long vehicleId;

@LazyCollection(LazyCollectionOption.FALSE)
@OneToMany(cascade=CascadeType.ALL,mappedBy="vehicle")
private Set<PersonVehAssnVO> personVehAssnVOSet=new HashSet<PersonVehAssnVO>();

private String vehicleName;

//getters & setters
}

人员车辆协会

package entity;

import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.OneToMany;
import javax.persistence.Table;

import org.hibernate.annotations.LazyCollection;
import org.hibernate.annotations.LazyCollectionOption;

@Entity
@Table(name ="PERSON_VEHICLE_ASSOC")
public class PersonVehAssnVO {
@EmbeddedId
private PKperson pkPerson;

@ManyToOne
@JoinColumns({ @JoinColumn(name = "pkPerson.name",referencedColumnName ="NAME"),
@JoinColumn(name = "pkPerson.dobDt",referencedColumnName ="DOB_DT")})
private Person person;

@ManyToOne
@JoinColumn(name = "VEHICLE_ID", referencedColumnName = "VEHICLE_ID")
private Vehicle vehicle;

//getters & setters
}


//**Save Method**
PKperson pkPerson = new PKperson();
SimpleDateFormat dtFormat = new SimpleDateFormat("yyyy-MM-dd");
Date date1 = dtFormat.parse("1984-12-14");
pkPerson.setName("Magesh");
pkPerson.setDobDt(date1);

Person person = new Person();
person.setPKperson(pkPerson);

Vehicle vehicle = new Vehicle();
vehicle.setName("Honda350");

PersonVehAssnVO perVehAssnVO = new PersonVehAssnVO();
PersonVehAssnVO.setPKperson(pkPerson);
PersonVehAssnVO.setVehicle(vehicle);

Set<PersonVehAssnVO>  assocSet = new HashSet<PersonVehAssnVO>();
assocSet.add(PersonVehAssnVO);

person.setpersonVehAssnVOSet(assocSet);
vehicle.setpersonVehAssnVOSet(assocSet);

Session session = getHibernateTemplate().getSessionFactory().openSession();
transaction = session.beginTransaction();

transaction.begin();    
session.save(person);       
transaction.commit();

// ============================================= ================

执行上述保存逻辑时，我收到错误“：[entity.PersonVehAssnVO#component[name,dobDt]{dobDt=magesh, dobDt=1984-12-14 00:00:00}]"

显示Sql提供“select personVehAssnVO_.NAME, personVehAssnVO_.DOB_DT, personVehAssnVO_.VEHICLE_ID as vehicle_34 from PERSON_VEHICLE_ASSOC where personVehAssnVO_.NAME=? and personVehAssnVO_.DOB_DT=?”

我希望将Person，Vehicle和association保存在一次保存中CASCADE ALL当我保存Person时。

任何帮助表示赞赏

Answer 1

使用@Temporal注释标记PKPerson中的日期：

@Temporal(TemporalType.TIME)
@Column(name="DOB_DT", nullable=false, length = 8)
private Date dobDt;

根据the Java Doc

必须为持久字段或属性指定此注释   类型java.util.Date和java.util.Calendar。它可能只是   为这些类型的字段或属性指定。

Temporal注释可以与Basic一起使用   注释，Id注释或ElementCollection注释   （当元素集合值具有这种时间类型时。

根据this SO question：

在普通Java API中，未定义时间的时间精度。在处理时态数据时，您可能想要描述数据库中的预期精度。时态数据可以有DATE，TIME或 TIMESTAMP精度（即实际日期，仅时间或两者）。使用 @Temporal注释可以对其进行微调。

我希望这能解决你的问题。您可以将TemporalType与数据库中与您的字段类型匹配的其他人互换。列长度也可以相应更改。

修改

我认为您还需要从Person和Vehicle类中的mappedBy="person"集的注释中删除mappedBy="vehicle"和PersonVehAssnVO，并将它们替换为完整的列属性，以便这些类可以是这段关系的所有者。否则，当您保存某个人时，它将忽略更新标有mappedby注释的任何属性，因为这意味着该人不是该关系的所有者。

JPA Cascade中的问题使用EmbeddedId保存在子级中

1 个答案: