Question

我与链接表中的额外文件（xml文件中的映射）有很多关系。使用标准api如何为产品名称添加限制？

public class Recipe implements Serializable{

    private int id_re;

    private String name;

    private Set<ProductRecipe> listOfRecipe_Product = new HashSet<>(0);
}


public class ProductRecipe implements Serializable{

    private ProductRecipeMapping id;

    private float quantity;
}

public class ProductRecipeMapping implements Serializable{

    private Product product;

    private Recipe recipe;
}

public class Product implements Serializable{

    private int id_p;

    private String name;
}

映射：

<class entity-name="recipe" name="Recipe" table="recipe">
        <id name="id_re" type="java.lang.Integer">
            <column name="id_re" />
            <generator class="identity" />
        </id>
        <set name="listOfRecipe_Product" table="recipe_product" lazy="false" fetch="select" cascade="all">
            <key>
                <column name="id_re" not-null="true" />
            </key>

            <one-to-many entity-name="productRecipe" />
        </set>
</class>

<class entity-name="productRecipe" name="ProductRecipe" table="recipe_product">
        <composite-id name="id" class="ProductRecipeMapping" >
            <key-many-to-one name="recipe" entity-name="recipe" column="id_re" />
            <key-many-to-one name="product" entity-name="product" column="id_p" />
        </composite-id>

        <property name="quantity" type="float" column="quantity" />

</class>    

<class entity-name="product" name="Product" table="product">

        <id name="id_p" type="java.lang.Integer" column="id_p">
            <generator class="identity" />
        </id>

        <property name="name" column="name" type="java.lang.String" not-null="true" length="255"/>

</class>

E.G。我使用带有名称测试的配方标准：

Criteria cr = session.createCriteria(Recipe.class);
cr.add(Restrictions.eq("name", "test"));

但我不知道如何获得产品列表名称的所有食谱像cr.add（Restrictions.eq（“product.name”，“test”））; （但没有工作）

我使用2个想法来解决这个问题，但没有任何作用：

1）Restrictions.eq("listOfRecipe_Product.id.product.name", "test") 但我收到错误org.hibernate.QueryException: could not resolve property: listOfRecipe_Product.id.product.name of: recipe

2）

cr.createCriteria("listOfRecipe_Product")
    .createCriteria("id")
    .createCriteria("product")
    .add(Restrictions.eq("name", "test"));

我收到错误org.hibernate.QueryException: Criteria objects cannot be created directly on components. Create a criteria on owning entity and use a dotted property to access component property: listOfRecipe_Product.id

Answer 1

您需要创建别名才能向映射实体添加约束;

e.g：

{{1}}

Hibernate Criteria API where子句的多对多关系

1 个答案: