JPA Criteria API：关联实体列表属性的复杂路径导航与查询

// Property Entity
@Entity
public class Property {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String address;

    @OneToOne(mappedBy = "property", cascade = CascadeType.ALL, orphanRemoval = true)
    @JsonManagedReference
    private Amenities amenities;

    // Getters and Setters
    public Long getId() { return id; }
    public void setId(Long id) { this.id = id; }
    public String getAddress() { return address; }
    public void setAddress(String address) { this.address = address; }
    public Amenities getAmenities() { return amenities; }
    public void setAmenities(Amenities amenities) { this.amenities = amenities; }
}

// Amenities Entity
@Entity
public class Amenities {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @OneToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "property_id")
    @JsonBackReference
    private Property property;

    @OneToMany(mappedBy = "amenities", cascade = CascadeType.ALL, orphanRemoval = true)
    @JsonManagedReference
    private List<Interiors> interiors = new ArrayList<>();

    // Getters and Setters
    public Long getId() { return id; }
    public void setId(Long id) { this.id = id; }
    public Property getProperty() { return property; }
    public void setProperty(Property property) { this.property = property; }
    public List<Interiors> getInteriors() { return interiors; }
    public void setInteriors(List<Interiors> interiors) { this.interiors = interiors; }
    public void addInterior(Interiors interior) {
        this.interiors.add(interior);
        interior.setAmenities(this);
    }
    public void removeInterior(Interiors interior) {
        this.interiors.remove(interior);
        interior.setAmenities(null);
    }
}

// Interiors Entity
@Entity
public class Interiors {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String name; // e.g., "Gym", "Pool", "Sauna"

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "amenities_id")
    @JsonBackReference
    private Amenities amenities;

    // Getters and Setters
    public Long getId() { return id; }
    public void setId(Long id) { this.id = id; }
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public Amenities getAmenities() { return amenities; }
    public void setAmenities(Amenities amenities) { this.amenities = amenities; }
}

// 假设 propertyRoot 是 Root<Property>
// criteriaBuilder.equal(propertyRoot.join("amenities").join("interiors").<String>get("name"), "Gym");

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.TypedQuery;
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.Arrays;
import java.util.List;

// 假设在一个Service或Repository类中
public class PropertyService {

    @PersistenceContext
    private EntityManager entityManager;

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

        // 1. 导航到 Amenities
        // Join<Property, Amenities> amenitiesJoin = propertyRoot.join("amenities");
        // 注意：如果 amenities 可能是 null，可以使用 JoinType.LEFT
        Join<Property, Amenities> amenitiesJoin = propertyRoot.join("amenities");

        // 2. 导航到 Interiors 集合
        // Join<Amenities, Interiors> interiorsJoin = amenitiesJoin.join("interiors");
        // 同样，如果 interiors 集合可能为空，并且你仍想返回 Property（即使没有匹配的 interiors），可以使用 JoinType.LEFT
        Join<Amenities, Interiors> interiorsJoin = amenitiesJoin.join("interiors");

        // 3. 创建 Predicate: interiorsJoin.get("name") in (interiorNames)
        Predicate nameInListPredicate = interiorsJoin.get("name").in(interiorNames);

        // 4. 将 Predicate 应用到 where 子句
        query.where(nameInListPredicate);

        // 5. 执行查询并返回结果
        TypedQuery<Property> typedQuery = entityManager.createQuery(query.distinct(true)); // distinct(true) 避免重复的 Property
        return typedQuery.getResultList();
    }

    // 示例用法
    public void demoQuery() {
        List<String> desiredInteriors = Arrays.asList("Gym", "Pool");
        List<Property> properties = findPropertiesWithSpecificInteriors(desiredInteriors);

        System.out.println("Properties with Gym or Pool:");
        for (Property p : properties) {
            System.out.println("Property ID: " + p.getId() + ", Address: " + p.getAddress());
            if (p.getAmenities() != null) {
                p.getAmenities().getInteriors().forEach(i -> System.out.println("  - Interior: " + i.getName()));
            }
        }
    }
}