Question

我得到的映射实体总是为null，但是已经设置了FetchType.EAGER。我有一个Booking实体类，它映射到另外两个实体 - Slot和Subscriber。当我获取预订实体时，这两个实体都为空

预订课程

John = 10
Lucy = 2
Tom = 4,
Hardy = 7
tom = 5
tom = 3
hardy = 7
Christoper = 4
Kim = 9
Tom = 4
john = 5 
John = 7
John = 6

广告位类

import java.util.Date;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import javax.persistence.Version;


@Entity
@Table(name = "BOOKING")
public class Booking {

    public Booking(){

    }

    @Id @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name = "id")
    private Integer id;

    @Column(name = "title")
    private String title;   

    @Column(name = "descr")
    private String desc;


    @OneToOne(fetch=FetchType.EAGER)
    @JoinColumn(name = "slotid",insertable = false, updatable = false)
    private Slot slot;

    private Integer slotid;

    private Integer subscriberid;


    @OneToOne(fetch=FetchType.EAGER)
    @JoinColumn(name = "subscriberid",insertable = false, updatable = false)
    private User subscriber;

    @Column(name = "created")
    @Temporal(TemporalType.TIMESTAMP)
    private Date created;

    public Integer getId() {
        return id;
    }

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

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    @OneToOne(fetch=FetchType.EAGER)
    @JoinColumn(name = "slotid",referencedColumnName="slotid")
    public Slot getSlot() {
        return slot;
    }

    public void setSlot(Slot slot) {
        this.slot = slot;
    }

    @OneToOne(fetch=FetchType.EAGER)
    @JoinColumn(name = "subscriberid",referencedColumnName="userid")
    public User getSubscriber() {
        return subscriber;
    }

    public void setSubscriber(User subscriber) {
        this.subscriber = subscriber;
    }

    public Date getCreated() {
        return created;
    }

    public void setCreated(Date created) {
        this.created = created;
    }

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

    public Integer getSlotid() {
        return slotid;
    }

    public void setSlotid(Integer slotid) {
        this.slotid = slotid;
    }

    public Integer getSubscriberid() {
        return subscriberid;
    }

    public void setSubscriberid(Integer subscriberid) {
        this.subscriberid = subscriberid;
    }



}

订阅者 - 用户类

import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import javax.persistence.Version;

@Entity
@Table(name="SLOT")
public class Slot {

    public Slot(){

    }

    @Id @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name="slotid")
    private Integer id;

    @OneToOne(fetch=FetchType.EAGER)
    @JoinColumn(name="ownerid",insertable = false, updatable = false)
    private User user;

    @Column(name="startdate")
    private Date startdate;

    @Column(name="enddate")
    private Date enddate;

    @Column(name="status")
    private String status;

    private Integer ownerid;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "created", nullable = false, updatable=false)
    @Version
    private Date created;

    public Integer getId() {
        return id;
    }

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

    public User getUser() {
        return this.user;
    }

    public void setUser(User owner) {
        this.user = owner;
    }




    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }

    public Integer getOwnerid() {
        return ownerid;
    }

    public void setOwnerid(Integer ownerid) {
        this.ownerid = ownerid;
    }

    public Date getCreated() {
        return created;
    }

    public void setCreated(Date created) {
        this.created = created;
    }

    public Date getStartdate() {
        return startdate;
    }

    public void setStartdate(Date startdate) {
        this.startdate = startdate;
    }

    public Date getEnddate() {
        return enddate;
    }

    public void setEnddate(Date enddate) {
        this.enddate = enddate;
    }

}

import java.util.Date; import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.OneToOne; import javax.persistence.PrimaryKeyJoinColumn; import javax.persistence.Table; import javax.persistence.Temporal; import javax.persistence.TemporalType; @Entity @Table(name="users") public class User { public User(){ } @Id@GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="userid") private Integer userid = 0; @Column(name = "name") private String name; @Column(name = "mobile") private String mobile; @Column(name = "password") private String password; @Column(name = "email") private String email; @Column(name = "type") private String userType; @OneToOne(fetch=FetchType.EAGER) @JoinColumn(name="cityid",insertable = false, updatable = false) private City city; private String cityid; @OneToOne(fetch=FetchType.EAGER) @JoinColumn(name="specialityid",insertable = false, updatable = false) private Speciality speciality; private Integer specialityid; @Column(name="medregno") private String regno; @Column(name="refcode") private String referalcode; public String getRegno() { return regno; } public void setRegno(String regno) { this.regno = regno; } public String getReferalcode() { return referalcode; } public void setReferalcode(String referalcode) { this.referalcode = referalcode; } @Column(name = "gender") private String gender; @Column(name = "active") private boolean active; @Temporal(TemporalType.TIMESTAMP) @Column(name = "updated") private Date updated; @Temporal(TemporalType.TIMESTAMP) @Column(name = "created") private Date created; @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; User other = (User) obj; if (userid != other.userid) return false; return true; } public Integer getUserid() { return userid; } public void setUserid(Integer userid) { this.userid = userid; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getMobile() { return mobile; } public void setMobile(String mobile) { this.mobile = mobile; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public String getUserType() { return userType; } public void setUserType(String userType) { this.userType = userType; } public City getCity() { return city; } public void setCity(City city) { this.city = city; } public String getGender() { return gender; } public void setGender(String gender) { this.gender = gender; } public boolean isActive() { return active; } public void setActive(boolean active) { this.active = active; } public Date getCreated() { return created; } public void setCreated(Date created) { this.created = created; } public Date getUpdated() { return updated; } public void setUpdated(Date updated) { this.updated = updated; } public String getCityid() { return cityid; } public void setCityid(String cityid) { this.cityid = cityid; } public Speciality getSpeciality() { return speciality; } public void setSpeciality(Speciality speciality) { this.speciality = speciality; } public Integer getSpecialityid() { return specialityid; } public void setSpecialityid(Integer specialityid) { this.specialityid = specialityid; } }和booking.getSlot()返回booking.getSubscriber()

如果我在映射时错过了一些配置，请告诉我

EDIT1 添加了实体加载方式的代码

null

我正在保存实体并重新加载它。

Answer 1

它不起作用，因为Hibernate正在重新调整它已经在其第一级缓存中的相同实例，该缓存没有引用其他2个实体中的任何一个。

要解决此问题，您必须执行session.refresh(booking)而不是执行查询。

Answer 2

在您的代码中：

booking.setSlotid(slotid);
booking.setSubscriberid(subscriberid);

您只是设置整数值而不是对象。而不是这样，尝试设置对象：

booking.setSlot(new Slot(slotid));
booking.setSubscriber(new Subscriber(subscriberid));

但正如@Augusto所说，你在会话中所拥有的关联（Slot and Subscriber）并不是完整的对象，它们只包含它们的id。这就是为什么你不能得到这些对象的其他领域。

使用@JoinColumn在@OneToOne上映射实体null

2 个答案: