Java

Question

我在玩 Hibernate 和 Postgres。我有一个用户Class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;
}
}

和一个地址Class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;
}
}

主要class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 class 时，用户对象的 HomeAddress 和 OfficeAddress 都有值（OfficeAddress），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地址对象，然后将地址对象设置为 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);

然后将值设置为包含 Office 地址详细信息的地址对象，然后将地址对象设置为 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);

如果我使用两个 Address 对象（我的 MainClass 中的 homeAddr 和 offAddr 对象来设置 userDetails 对象的 homeAddress 和 OfficeAddress 值，这完全没问题。

但我想尝试使用一个地址对象为家庭地址和办公室地址设置不同的值。

我知道我们可以使用相同的地址对象来为 UserDetails Class 的 Home 和 Office Address 字段设置值。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）

我什至使用调试模式进行调试，以了解为什么 homeAddress 值被 OfficeAddress 值覆盖。

非常感谢任何有助于理解为什么家庭地址值被办公室地址值覆盖的信息。提前致谢。

此致，迪瓦卡

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住址时，addr 和用户的 homeAddress 引用同一个地址对象，对其的更改将反映在两个地方。

Java - 使用地址对象更新用户对象的两个复杂字段（办公室地址和家庭地址）

Java - Using an Address object to update two complex fields(Office address & Home Address) of User object

setter