抓取一對多對象在Hibernate中

Question

我下面的兩個實體，

用戶

@Entity 
@EqualsAndHashCode 
public class User extends BaseEntity{ 

    @Getter @Setter 
    private String msid; 
    @OneToMany(cascade = CascadeType.ALL, mappedBy = "sender") 
    @Getter 
    private List<Media> sentList; 
    @OneToMany(cascade = CascadeType.ALL, mappedBy = "receiver") 
    @Getter 
    private List<Media> receivedList; 

    protected User(){ 
    super(); 
    } 

    public User(String yguid) { 
    this(); 
    this.yguid = yguid; 
    this.receivedList = new ArrayList<>(); 
    this.sentList = new ArrayList<>(); 
    } 
} 

媒體

@Entity 
@EqualsAndHashCode 
public class Media extends BaseEntity{ 

    @Getter @Setter 
    private String mediaId; 
    @Getter @Setter 
    private String url; 
    @ManyToOne 
    @JoinColumn(name="sender") 
    @Getter @Setter 
    private User sender; 
    @ManyToOne 
    @JoinColumn(name="receiver") 
    @Getter @Setter 
    private User receiver; 

    public Media() { 
    super(); 
    } 

    public Media(String mediaId, String url, User sender, User receiver) { 
    this(); 
    this.mediaId = mediaId; 
    this.url = url; 
    this.sender = sender; 
    this.receiver = receiver; 
    } 
} 

無論從BaseEntity

public abstract class BaseEntity { 
    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO) 
    private final Long id; 

    public BaseEntity() { 
    id = null; 
    } 
} 

繼承我想爲我們提取所有媒體呃。這是我的代碼

public List<Media> getReceivedMediaForUser(User user){ 
    Session session = sessionFactory.openSession(); 
    Query query = session.createQuery("FROM Media m WHERE m.receiver = :user"); 
    //parse query to get result 
    session.close(); 
    // 
    return null; 
    } 

這不會編譯，有人可以幫助我形成正確的查詢並獲得結果。我是Spring和Hibernate的新手。

Answer 1

你可以做到這一點，如下圖所示（這是按照不解決方案的例子。實現的解決方案因此您的要求），

Query query = session.createSQLQuery(
"select * from stock s where s.stock_code = :stockCode") 
.addEntity(Stock.class) 
.setParameter("stockCode", "7277"); 
List result = query.list(); 

您的解決方案可能是

Session session = sessionFactory.openSession(); 
    Query query = session.createQuery("select * FROM Media m WHERE m.receiver = :user") 
    .addEntity(Media.class) 
    .setParameter("user", "xyz"); 
    List result = query.list(); 
    session.close();