Hibernate的4.3合并级联通过多个列出了与嵌入式ID

问题描述 投票：1回答：1

休眠4.3.11

我有一个问题，节省休眠以下对象图。雇主正在使用合并（）方法保存。

Employer 
   |_ List<EmployerProducts> employerProductsList; 
         |_ List<EmployerProductsPlan> employerProductsPlan;

用人单位与EmployerProducts有一个自动生成的PK。所述EmployerProductsPlan是由所述EmployerProducts ID和与该计划代码的字符串的组合键。

当有在EmployerProducts列表级联到List<EmployerProductsPlan>临时对象时发生错误。我遇到的第一个错误，我一直在试图让过去是内部休眠NPE。这里这篇文章极好地描述，我有这将导致空指针Hibernate NullPointer on INSERTED id when persisting three levels using @Embeddable and cascade问题

该OP留下评论指定他们做了什么来解决，但改变所建议的映射时我结束了一个不同的错误。更改映射后，我现在越来越

org.hibernate.NonUniqueObjectException: A different object with the same identifier value was already associated with the session : [com.webexchange.model.EmployerProductsPlan#com.webexchange.model.EmployerProductsPlanId@c733f9bd]

由于其他库的依赖，我不能上方版本4.3.x在这个时候升级。该项目是利用弹簧引导起动数据JPA 1.3.3。没有其他工作正在上比调用合并（），将通过雇主对象以外的会话中执行。

下面是每个类的映射：

雇主

@Entity
@Table(name = "employer")
@lombok.Getter
@lombok.Setter
@lombok.EqualsAndHashCode(of = {"employerNo"})
public class Employer implements java.io.Serializable {

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "EMPLOYER_NO", unique = true, nullable = false)
    private Long employerNo;

     .....


    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "employer", orphanRemoval = true)
    private List<EmployerProducts> employerProductsList = new ArrayList<>(0);
}

EmployerProducts

@Entity
@Table(name = "employer_products")
@Accessors(chain = true) // has to come before @Getter and @Setter
@lombok.Getter
@lombok.Setter
@lombok.EqualsAndHashCode(of = {"employerProductsNo"})

public class EmployerProducts implements Serializable {

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "employer_products_no", unique = true, nullable = false)
    private Long employerProductsNo;

    @ManyToOne
    @JoinColumn(name = "employer_no", nullable = false)
    private Employer employer;

    ......

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "employerProducts", orphanRemoval = true)
    private List<EmployerProductsPlan> employerProductsPlanList = new ArrayList<>(0);
}

EmployerProductsPlan

@Accessors(chain = true) // has to come before @Getter and @Setter
@lombok.Getter
@lombok.Setter
@lombok.EqualsAndHashCode(of = {"id"})
@Entity
@Table(name="employer_products_plan")
public class EmployerProductsPlan implements Serializable {

    @EmbeddedId
    @AttributeOverrides({ @AttributeOverride(name = "plan", column = @Column(name = "epp_plan", nullable = false)),
            @AttributeOverride(name = "employerProductsNo", column = @Column(name = "employer_products_no", nullable = false)) })
    private EmployerProductsPlanId id;

    @ManyToOne
    @JoinColumn(name = "employer_products_no")
    @MapsId("employerProductsNo")
    private EmployerProducts employerProducts;

}

我上面填充与正在保存EmployerProducts对象的相同实例中employerProducts。它是短暂的，没有ID填充，因为它没有在数据库现有呢。

EmployerProductsPlanId

@Accessors(chain = true) // has to come before @Getter and @Setter
@lombok.Getter
@lombok.Setter
@lombok.EqualsAndHashCode(of = {"plan", "employerProductsNo"})
@Embeddable
public class EmployerProductsPlanId implements Serializable {

    private String plan;

    private Long employerProductsNo;

   // This was my previous mapping that was causing the internal NPE in hibernate
   /* @ManyToOne
    @JoinColumn(name = "employer_products_no")
    private EmployerProducts employerProducts;*/
}

UPDATE：显示Struts控制器和DAO。雇主对象永远不会从分贝保存之前加载。支柱是创建从HTTP请求的参数此整个对象图。

Struts的2.5控制器

@lombok.Getter
@lombok.Setter
public class EditEmployers extends ActionHelper implements Preparable {

    @Autowired
    @lombok.Getter(AccessLevel.NONE)
    @lombok.Setter(AccessLevel.NONE)
    private IEmployerDao employerDao;

    private Employer entity;

    ....

    public String save() {

        beforeSave();

        boolean newRecord = getEntity().getEmployerNo() == null || getEntity().getEmployerNo() == 0;
        Employer savedEmployer = newRecord ?
                employerDao.create(getEntity()) :
                employerDao.update(getEntity());

        setEntity(savedEmployer);

        return "success";
    }


    private void beforeSave() {
        Employer emp = getEntity();

        // associate this employer record with any products attached
        for (EmployerProducts employerProduct : emp.getEmployerProductsList()) {
            employerProduct.setEmployer(emp);

            employerProduct.getEmployerProductsPlanList().forEach(x ->
                    x.setEmployerProducts(employerProduct));
        }

        // check to see if branding needs to be NULL.  It will create the object from the select parameter with no id
        //  if a branding record has not been selected
        if (emp.getBranding() != null && emp.getBranding().getBrandingNo() == null) {
            emp.setBranding(null);
        }
    }



}

employer DAO

@Repository
@Transactional
@Service
@Log4j
public class EmployerDao  extends WebexchangeBaseDao implements IEmployerDao  {

    private Criteria criteria() {
        return getCurrentSession().createCriteria(Employer.class);
    }

    @Override
    @Transactional(readOnly = true)
    public Employer read(Serializable id) {
        return (Employer)getCurrentSession().load(Employer.class, id);
    }

    @Override
    public Employer create(Employer employer) {
        getCurrentSession().persist(employer);

        return employer;
    }

    @Override
    public Employer update(Employer employer) {

        getCurrentSession().merge(employer);

        return employer;
    }


}
java hibernate jpa hibernate-mapping
1个回答
0
投票

截至目前，我的解决办法是通过EmployerProducts循环并检查新记录。我叫调用合并（）父用人单位面前的新的一种坚持。我也感动的逻辑我在我的Struts的行动有它的所有键关联到DAO来代替。下面是我的更新（）在雇主DAO方法现在看起来像

public Employer update(Employer employer) {


    // associate this employer record with any products attached
    for (EmployerProducts employerProduct : employer.getEmployerProductsList()) {
        employerProduct.setEmployer(employer);

        if (employerProduct.getEmployerProductsNo() == null) {
            // The cascade down to employerProductsPlanList has issues getting the employerProductsNo
            // automatically if the employerProduct does not exists yet.  Persist the new employer product
            // before we try to insert the new composite key in the plan
            // https://stackoverflow.com/questions/54517061/hibernate-4-3-cascade-merge-through-multiple-lists-with-embeded-id
            List<EmployerProductsPlan> plansToBeSaved = employerProduct.getEmployerProductsPlanList();
            employerProduct.setEmployerProductsPlanList(new ArrayList<>());
            getCurrentSession().persist(employerProduct);

            // add the plans back in
            employerProduct.setEmployerProductsPlanList(plansToBeSaved);
        }

        // associate the plan with the employer product
        employerProduct.getEmployerProductsPlanList().forEach(x ->
                    x.getId().setEmployerProductsNo(employerProduct.getEmployerProductsNo())
        );

    }


    return (Employer)getCurrentSession().merge(employer);
}
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