spring - 如何使用通用 dao 和服务层获取特定的继承实体

Question

在我的 spring mvc 项目上工作时，我面临以下问题：我有 UnitAppUser、VStanAppUser 和 RjuAppUser 实体类，它们扩展了 User 实体。用户实体存储一些通用信息。其余继承实体存储对特定实体的引用（UnitAppUser 具有字段 Unit 类型，VStanAppUser 具有 VStan 类型，依此类推）。这是我的父用户实体

@Entity
@Inheritance(strategy=InheritanceType.JOINED)
@Table(name="app_user")
    public class User implements Serializable {
    /**
     * 
     */
    private static final long serialVersionUID = 6628717324563396999L;

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

@NotEmpty
@Column(name="SSO_ID", unique=true, nullable=false)
private String ssoId;

@NotEmpty
@Column(name="PASSWORD", nullable=false)
private String password;

@NotEmpty
@Column(name="FIRST_NAME", nullable=false)
private String firstName;

@NotEmpty
@Column(name="LAST_NAME", nullable=false)
private String lastName;

@NotEmpty
@Column(name="EMAIL", nullable=false)
private String email;
}

这是我的孩子班：

@Entity
@Table(name = "unit_app_user")
public class UnitAppUser extends User implements Serializable {

@JoinColumn(name = "UNITWORK", referencedColumnName = "ID")
@ManyToOne(optional = false)
private UnitDepart unitdepart;

public UnitDepart getWorkat() {
    return unitdepart;
}

public void setWorkat(UnitDepart unitdepart) {
    this.unitdepart = unitdepart;
}
}
@Entity
@Table(name="rju_app_user")
public class RjuAppUser extends User implements Serializable{

@JoinColumn(name = "workrju", referencedColumnName = "id")
@ManyToOne(optional = false)
private Rju rju;
public Rju getWorkat() {
    return rju;
}
public void setWorkat(Rju rju) {
    this.rju = rju;
}
}

最后是我的 Vstan 实体：

@Entity
@Table(name="vstan_app_user")
public class VstanAppUser extends User implements Serializable{

@JoinColumn(name = "WORKSTATION", referencedColumnName = "kod")
@ManyToOne(optional = false)
private Vstan vstan;

public Vstan getWorkat() {
    return vstan;
}

public void setWorkat(Vstan vstan) {
    this.vstan = vstan;
} 
}

如何编写通用 dao 和服务来获取特定实体？结果我应该有这样的东西

userService.findBySSOId("somessoId").getWorkat() //should return UnitDepart, Rju or VStan

标签： springhibernatespring-mvcjpaorm