Hibernate标准连接表问题

Question

我有3个实体,如下所示.我想写一个提取产品的查询.在此查询中,参数是optionValues id的列表.

现在我的问题是如何加入这些实体？

产品:

 public class Product{
   //other col

    @OneToMany(mappedBy = "product")
    private Set<Attribute> attributeSet = new HashSet<>();
 }

属性:

public class Attribute{
  @OneToOne
  @JoinColumn(name = "OPTION_VALUE_ID")
  private OptionValue optionValue;

  @ManyToOne
  @JoinColumn(name="PRODUCT_ID",referencedColumnName="id")
  private Product product;
}

optionValue:

 public class OptionValue{
     @Column(name = "id")
     private Long id;

    @Column(name = "value",updatable = true)
    private String value;
 }

我写了一个查询,但我认为我的代码不是一个好的解决方案.

 Criteria aCriteria = null;
    if (!optionValueList.isEmpty()) {
        aCriteria = currentSession().createCriteria(Attribute.class, "attribute");
        aCriteria.createAlias("attribute.optionValue", "optionValue");
        aCriteria.add(Restrictions.in("optionValue.id", optionValueList));
        attributes = aCriteria.list();
    }
    PagingData<Product> pagingData = new PagingData<>();
    Criteria criteria = currentSession().createCriteria(Product.class, "product");
    if (!attributes.isEmpty()) {
        for (Attribute attribute:attributes){
            longList.add(attribute.getId());
        }
        criteria.createAlias("product.attributeSet", "attribute");
        criteria.add(Restrictions.in("attribute.id", longList));
        criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);

    }

Answer 1

总体思路是从创建要返回的对象的条件开始，然后通过添加连接的条件来进一步进行。因此，我从Parent类开始，添加限定符，最后得到大多数嵌套元素OptionValue.

下面的代码未经测试，但您应该明白：

Criteria criteria = currentSession()
  .createCriteria(Product.class)
  .createCriteria("attributeSet", "join_between_product_and_attribute");

if (!attributes.isEmpty()) {
  Set<String> attributeIds = new HashSet<>();
  for (Attribute attribute : attributeList) {
    attributeIds.add(attribute.getId());
  }
  criteria.add(Restrictions.in("id", attributeIds));
}

criteria = criteria.createCriteria("optionValue", "join_between_attribute_optionvalue");
if (!optionValueList.isEmpty()) {
  criteria.add(Restrictions.in("id", optionValueList));
}