Question

我有一个实体电影，然后是人物实体。电影与Person有一个ManyToMany关系：一个是铸造，另一个是生产，另一个是直接。

所以我的问题是给了一个人如何获得他所采取的行动，制作和指导的电影。

//人员类：

@Entity
public class Person implements Serializable{

private static final long serialVersionUID = 1L;

@Id
@JsonView(Views.Private.class)
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long idPerson;
private String name;
private String surnames;
private boolean isActor;
private boolean isDirector;
private boolean isProducer;

@ManyToMany(mappedBy = "casting")
private Set<Movie> moviesCasting = new HashSet<>();

@ManyToMany(mappedBy = "movieDirection")
private Set<Movie> movieDirection = new HashSet<>();

@ManyToMany(mappedBy = "movieProduction")
private Set<Movie> movieProduction = new HashSet<>();

//电影课

 @Entity
 public class Movie implements Serializable {

private static final long serialVersionUID = 1L;    
@ManyToMany(cascade = {CascadeType.ALL})
@JoinTable(name = "casting_movie",
        joinColumns = @JoinColumn(name = "id"),
        inverseJoinColumns = @JoinColumn(name = "idPerson")
)
private Set<Person> casting = new HashSet<>();

public Set<Person> getCasting() {
    casting.size();
    return casting;
}

@ManyToMany(cascade = {CascadeType.ALL})
@JoinTable(name = "production_movie",
        joinColumns = @JoinColumn(name = "id"),
        inverseJoinColumns = @JoinColumn(name = "idPerson")
)
private Set<Person> movieProduction = new HashSet<>();

public Set<Person> getMovieProduction() {
    movieProduction.size();
    return movieProduction;
}

@ManyToMany(cascade = {CascadeType.ALL})
@JoinTable(name = "direction_movie",
        joinColumns = @JoinColumn(name = "id"),
        inverseJoinColumns = @JoinColumn(name = "idPerson")
)

private Set<Person> movieDirection = new HashSet<>();
getters and setters(...)

当我想获取有关某人的信息时，我收到错误：未能懒惰地初始化角色集合Movies.casting“

如果我给了一个人，我想获得每个“电影摄影”，我必须双向创建ManyToMany关系吗？

Answer 1

您可以拥有另一个实体，该实体将具有多个对Movie和Person的引用，并具有一个额外的字段RelationshipType（具有值Casting，Production，Direction等）。你应该为它创建一个枚举。

通过这样做，你可以获取一个人的定向电影（来自新实体）： findByMovieAndPersonAndRelationshipType(Movie movie, Person person, RelationshipType.DIRECTED);

P.S。摆脱你所有的多对多关系

JPA ManyToMany关系休眠

1 个答案: