在另一個Spring實體中使用Spring實體

Question

當我嘗試向“用戶”類中指定的ArrayList中添加“游戲”對象時出現以下錯誤。 這個動作是在我的控制器類中完成的：

"org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.billsheng.huddlespringmvc.models.Game; nested exception is java.lang.IllegalStateException: org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.billsheng.huddlespringmvc.models.Game"

用戶實體

@Data
@Entity
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;

    private String email;
    private String firstName;
    private String lastName;
    private String password;
    private String chosenTeam;
    private int gamesPlayed;
    private int gamesWon;

    @ElementCollection
    private List<Game> games = new ArrayList<>();

    public User(String firstName, String lastName, String email, String password, String chosenTeam, int gamesPlayed, int gamesWon, ArrayList<Game> games) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
        this.password = password;
        this.chosenTeam = chosenTeam;
        this.gamesPlayed = gamesPlayed;
        this.gamesWon = gamesWon;
        this.games = games;
    }

    public User(String firstName, String lastName, String email, String password, String chosenTeam) {
        this(firstName, lastName, email, password, chosenTeam, 0, 0, null);
    }

    public User(int gamesPlayed, int gamesWon, ArrayList<Game> games) {
        this.gamesPlayed = gamesPlayed;
        this.gamesWon = gamesWon;
        this.games = games;
    }

    public User() {
    }

//getters and setters
}

游戲實體

@Data
@Entity
public class Game {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;
    private String homeTeam;
    private String awayTeam;
    private Date date;
    private String location;
    private String bettingOdds;
    private boolean inProgress;
    private boolean isReviewed;

//getters and setters
}

我做了一些研究，我相信這個問題源於我在User對象中使用Game對象，但是我不確定具體是什么問題。 感謝所有幫助。

Answer 1

@ElementCollection不應與實體集合一起使用； 它與@Embeddable集合@Embeddable 。 如果Thing是實體，則不要使用@ElementCollection ，而要使用@OneToMany 。

@ElementCollection ：定義基本類型或可嵌入類的實例的集合

您可以使用@OneToMany映射來建立用戶和游戲實體之間的關系。

User.java

@OneToMany(cascade=CascadeType.ALL,fetch= FetchType.LAZY,mappedBy = "user")
private List<Game> games = new ArrayList<>();

//getters and setters

Game.java

@ManyToOne
private User user;

//getters and setters