[英]Spring Data Join with Specifications
我正在嘗試轉換這個原始 sql 查詢:
select product.* from following_relationship
join product on following_relationship.following=product.owner_id
where following_relationship.owner=input
進入 Spring Data 規范,我認為到目前為止我的問題是加入這些表。
這是我目前在規范中的轉換:
protected Specification<Product> test(final User user){
return new Specification<Product>() {
@Override
public Predicate toPredicate(Root<Product> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
Join<FollowingRelationship,Product> pfJoin = query.from(FollowingRelationship.class).join("following");
pfJoin.on(cb.equal(pfJoin.get("following"),"owner"));
return query.where(cb.equal(pfJoin.get("following"),user)).getGroupRestriction();
}
};
}
我得到這個例外:
Request processing failed; nested exception is org.springframework.dao.InvalidDataAccessA
piUsageException: org.hibernate.hql.internal.ast.InvalidWithClauseException: with clause can only reference columns in the driving table
我想補充一點,我是 Spring 框架的新手,例如這是我在 Spring 上的第一個應用程序,所以我為新手問題道歉;)
編輯:添加實體產品,FollowingRelationShip
Entity
@JsonIdentityInfo(generator = ObjectIdGenerators.IntSequenceGenerator.class, property = "json_id_prop")
public class FollowingRelationship extends BaseEntity {
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "OWNER", referencedColumnName = "uuid")
private User owner;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "FOLLOWING", referencedColumnName = "uuid")
private User following;
public User getOwner() {
return owner;
}
public void setOwner(User owner) {
this.owner = owner;
}
public User getFollowing() {
return following;
}
public void setFollowing(User following) {
this.following = following;
}
}
@Entity
@Table(name = "product")
@JsonIdentityInfo(generator = ObjectIdGenerators.IntSequenceGenerator.class, property = "json_id_prop")
public class Product extends BaseEntity {
@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "OWNER_ID", referencedColumnName = "uuid")
private User owner;
@NotNull
private String name;
@NotNull
private String description;
@NotNull
private String price;
@NotNull
private String brand;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String getPrice() {
return price;
}
public void setPrice(String price) {
this.price = price;
}
public String getBrand() {
return brand;
}
public void setBrand(String brand) {
this.brand = brand;
}
public User getOwner() {
return owner;
}
public void setOwner(User owner) {
this.owner = owner;
}
}
Product 和FollowingRelationShip 實體沒有任何明確的關系,因此加入我的實現about.What 我想要實現的是從Spring 數據規范中另一個用戶遵循的所有用戶中獲取所有產品。
編輯:好的,我在這里搞得一團糟,但我希望這次我更接近正確的答案。
考慮(id 是自動生成的,如 John 等的 1):
INSERT INTO some_user (name) VALUES ('John');
INSERT INTO some_user (name) VALUES ('Ariel');
INSERT INTO some_user (name) VALUES ('Brian');
INSERT INTO some_user (name) VALUES ('Kelly');
INSERT INTO some_user (name) VALUES ('Tom');
INSERT INTO some_user (name) VALUES ('Sonya');
INSERT INTO product (owner_id,name) VALUES (1,'Nokia 3310');
INSERT INTO product (owner_id,name) VALUES (2,'Sony Xperia Aqua');
INSERT INTO product (owner_id,name) VALUES (3,'IPhone 4S');
INSERT INTO product (owner_id,name) VALUES (1,'Xiaomi MI5');
INSERT INTO product (owner_id,name) VALUES (3,'Samsung Galaxy S7');
INSERT INTO product (owner_id,name) VALUES (3,'Sony Xperia Z3');
INSERT INTO following_relationship (follower_id, owner_id) VALUES (4,1);
INSERT INTO following_relationship (follower_id, owner_id) VALUES (5,1);
INSERT INTO following_relationship (follower_id, owner_id) VALUES (4,2);
INSERT INTO following_relationship (follower_id, owner_id) VALUES (6,2);
INSERT INTO following_relationship (follower_id, owner_id) VALUES (6,3);
INSERT INTO following_relationship (follower_id, owner_id) VALUES (1,3);
基於您提供的實體的簡化版本,以及 SomeUser 實體,例如:
@Entity
public class FollowingRelationship {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;
@ManyToOne(cascade=CascadeType.ALL, fetch=FetchType.EAGER)
@JoinColumn(name = "owner_id")
SomeUser owner;
@ManyToOne(cascade=CascadeType.ALL, fetch=FetchType.EAGER)
@JoinColumn(name = "follower_id")
SomeUser follower;
...
@Entity
public class Product {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;
@ManyToOne()
@JoinColumn(name = "owner_id")
private SomeUser owner;
@Column
private String name;
...
@Entity
public class SomeUser {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;
@Column
private String name;
@OneToMany(mappedBy = "owner")
private Set<Product> products = new HashSet<Product>();
@OneToMany(mappedBy = "owner")
private Set<FollowingRelationship> ownedRelationships = new HashSet<FollowingRelationship>();
@OneToMany(mappedBy = "follower")
private Set<FollowingRelationship> followedRelationships = new HashSet<FollowingRelationship>();
我創建了如下規范:
public static Specification<Product> joinTest(SomeUser input) {
return new Specification<Product>() {
public Predicate toPredicate(Root<Product> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
Join<Product,SomeUser> userProd = root.join("owner");
Join<FollowingRelationship,Product> prodRelation = userProd.join("ownedRelationships");
return cb.equal(prodRelation.get("follower"), input);
}
};
}
現在,我們可以使用以下命令執行查詢:
SomeUser someUser = someUserRepository.findOne(Specification.where(ProductSpecifications.userHasName("Kelly")));
List<Product> thatProducts = productRepository.findAll(Specification.where(ProductSpecifications.joinTest(someUser)));
System.out.println(thatProducts.toString());
我們得到:
[Product [id=1, name=Nokia 3310], Product [id=4, name=Xiaomi MI5], Product [id=2, name=Sony Xperia Aqua]]
在我看來,這相當於:“從另一個用戶關注的所有用戶那里獲取所有產品”——獲取凱利關注的所有用戶的產品。
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