Java - 使用地址对象更新用户对象的两个复杂字段(办公地址和家庭住址)

Question

我在玩Hibernate和Postgres。我有一个用户类如下

import javax.persistence.AttributeOverride;
import javax.persistence.AttributeOverrides;
import javax.persistence.Column;
import javax.persistence.Embedded;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Lob;
import javax.persistence.Table;
@Entity
@Table(name="USER_DETAILS")
public class UserDetails {
@Id @GeneratedValue
private int userId;
private String userName;
@Temporal(TemporalType.DATE)
private Date joinedDate;
@Embedded
private Address homeAddress;
@Embedded
@AttributeOverrides({
@AttributeOverride(name="street", column = @Column(name="OFFICE_STREET_NAME")),
@AttributeOverride(name="city", column = @Column(name="OFFICE_CITY_NAME")),
@AttributeOverride(name="state", column = @Column(name="OFFICE_STATE_ABBR")),
@AttributeOverride(name="pincode", column = @Column(name="OFFICE_PIN_CODE"))
})
private Address officeAddress;
@Lob
@Type(type="text")
private String description;
public int getUserId() {
return userId;
}
public void setUserId(int userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public Date getJoinedDate() {
return joinedDate;
}
public void setJoinedDate(Date joinedDate) {
this.joinedDate = joinedDate;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public Address getHomeAddress() {
return homeAddress;
}
public void setHomeAddress(Address homeAddress) {
this.homeAddress = homeAddress;
}
public Address getOfficeAddress() {
return officeAddress;
}
public void setOfficeAddress(Address officeAddress) {
this.officeAddress = officeAddress;
}
}

以及地址类别，如下

import javax.persistence.Column;
import javax.persistence.Embeddable;
@Embeddable
public class Address {
@Column(name="STREET_NAME")
private String street;
@Column(name="CITY_NAME")
private String city;
@Column(name="STATE_NAME")
private String state;
@Column(name="PINCODE_NUMBER")
private String pincode;
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getPincode() {
return pincode;
}
public void setPincode(String pincode) {
this.pincode = pincode;
}
}

主类如下

import java.util.Date;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.loganathan.divakar.dto.Address;
import org.loganathan.divakar.dto.UserDetails;
public class HibernateTest {
public static void main(String[] args) {
// TODO Auto-generated method stub
UserDetails user = new UserDetails();
user.setUserName("First User");
user.setJoinedDate(new Date());
user.setDescription("First User Description");
Address addr = new Address();
addr.setStreet("Home Street");
addr.setCity("Home City");
addr.setState("Home State Abbr");
addr.setPincode("Home PinCode");
user.setHomeAddress(addr);
addr.setStreet("Office Street");
addr.setCity("Office City");
addr.setState("Office State");
addr.setPincode("Office PinCode");
user.setOfficeAddress(addr);
SessionFactory sessionFactory = new 
Configuration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(user);
session.getTransaction().commit();
session.close();
}
}

所以现在当我运行Main类时，HomeAddress&用户对象的OfficeAddress具有(OfficeAddress的(值，我有意使用相同的地址对象"addr"。

Address addr = new Address();

首先将值设置为具有家庭地址详细信息的addr对象，然后将addr对象设置为UserDetails对象(用户(的homeAddress字段

addr.setStreet("Home Street");
addr.setCity("Home City");
addr.setState("Home State Abbr");
addr.setPincode("Home PinCode");
user.setHomeAddress(addr);

然后将值设置为具有Office地址详细信息的addr对象，然后将addr对象设置为UserDetails对象(用户(的officeAddress字段

addr.setStreet("Office Street");
addr.setCity("Office City");
addr.setState("Office State");
addr.setPincode("Office PinCode");
user.setOfficeAddress(addr); 

如果我在MainClass中使用两个Address对象(homeAddr和offAddr对象(来设置userDetails对象的homeAddress和OfficeAddress值，这完全可以。

但我想尝试使用一个Address对象为Home和Office Address设置不同的值。

我知道，从逻辑上讲，我们可以使用相同的地址对象来设置UserDetails类的Home和Office address字段的值。但我无法理解为什么homeAddress值被OfficeAddress值覆盖(即使在设置User.homeAddress字段之后，甚至在输入OfficeAddress值之前(

我甚至使用调试模式进行了调试，以了解为什么homeAddress值被OfficeAddress值覆盖。

任何有助于理解家庭地址值被Office地址值覆盖的原因的信息都将不胜感激。提前谢谢。

谨致问候，Divakar

Answer 1

发生这种情况是因为您仍在使用相同的地址对象。如果您希望它们是单独的地址，则必须创建一个新地址。

Address addr = new Address();
addr.setStreet("Home Street");
addr.setCity("Home City");
addr.setState("Home State Abbr");
addr.setPincode("Home PinCode");
user.setHomeAddress(addr);
addr = new Address(); // make a new address
addr.setStreet("Office Street");
addr.setCity("Office City");
addr.setState("Office State");
addr.setPincode("Office PinCode");
user.setOfficeAddress(addr); 

当您将地址设置为家庭地址时，addr和用户的homeAddress引用的是同一个address对象，对它的更改将反映在这两个位置。