JPA Criteria API：关联实体路径导航与集合字段过滤教程

// Property Entity
class Property {
    // ... 其他属性
    @OneToOne(mappedBy = "property", cascade = CascadeType.ALL)
    @JsonManagedReference
    private Amenities amenities;
    // ... getter/setter
}

// Amenities Entity
class Amenities {
    // ... 其他属性
    @OneToMany(mappedBy = "amenities", cascade = CascadeType.ALL)
    @JsonManagedReference
    private List<Interiors> interiors;
    // ... getter/setter
}

// Interiors Entity
public class Interiors {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id;
    private String name; // 例如："Gym", "Pool", "Sauna"
    // ... getter/setter
}

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Join;
import javax.persistence.criteria.Root;
import javax.persistence.criteria.Predicate;
import java.util.List;

// 假设在一个Spring Data JPA Repository或Service中
public class PropertyService {

    @PersistenceContext
    private EntityManager entityManager;

    public List<Property> findPropertiesWithInteriorName(String interiorName) {
        CriteriaBuilder cb = entityManager.getCriteriaBuilder();
        CriteriaQuery<Property> cq = cb.createQuery(Property.class);
        Root<Property> propertyRoot = cq.from(Property.class);

        // 1. 导航到 Amenities (OneToOne 关联)
        // Join<源实体, 目标实体>
        Join<Property, Amenities> amenitiesJoin = propertyRoot.join("amenities");

        // 2. 导航到 Interiors (OneToMany 关联)
        // 此时 interiorsJoin 代表了 Amenities 实体中 List<Interiors> 集合里的每一个 Interiors 元素
        Join<Amenities, Interiors> interiorsJoin = amenitiesJoin.join("interiors");

        // 3. 构建谓词：interiorsJoin 的 name 属性等于指定名称
        Predicate namePredicate = cb.equal(interiorsJoin.get("name"), interiorName);

        // 4. 将谓词应用到查询的 where 子句
        cq.where(namePredicate);

        // 5. 执行查询并返回结果
        return entityManager.createQuery(cq).getResultList();
    }

    // 调用示例
    public static void main(String[] args) {
        // 假设已经获取到 EntityManager 实例
        // PropertyService service = new PropertyService();
        // List<Property> gymProperties = service.findPropertiesWithInteriorName("Gym");
        // gymProperties.forEach(p -> System.out.println("Property ID: " + p.getId()));
    }
}

import java.util.Arrays;
import java.util.List;

public class PropertyService {
    // ... (同上，省略EntityManager注入和findPropertiesWithInteriorName方法)

    public List<Property> findPropertiesWithInteriorNamesInList(List<String> interiorNames) {
        CriteriaBuilder cb = entityManager.getCriteriaBuilder();
        CriteriaQuery<Property> cq = cb.createQuery(Property.class);
        Root<Property> propertyRoot = cq.from(Property.class);

        Join<Property, Amenities> amenitiesJoin = propertyRoot.join("amenities");
        Join<Amenities, Interiors> interiorsJoin = amenitiesJoin.join("interiors");

        // 构建 IN 谓词：interiorsJoin 的 name 属性在 interiorNames 列表中
        Predicate inPredicate = interiorsJoin.get("name").in(interiorNames);

        cq.where(inPredicate);

        return entityManager.createQuery(cq).getResultList();
    }

    // 调用示例
    public static void main(String[] args) {
        // ...
        // List<String> desiredInteriors = Arrays.asList("Gym", "Pool");
        // List<Property> gymOrPoolProperties = service.findPropertiesWithInteriorNamesInList(desiredInteriors);
        // gymOrPoolProperties.forEach(p -> System.out.println("Property ID: " + p.getId()));
    }
}