Spring不将组合键实体映射到数据库

问题描述

我有两个实体User和Focus，我必须为其存储一个等级，这样一个User才能具有多个Focus的排名，并且一个Focus可能有许多用户。为了解决这个问题，我遵循了https://www.baeldung.com/jpa-many-to-many第3部分，其中有以下2个类：

@Entity(name = "UserBaseratings")
public class rating {

    @EmbeddedId
    ratingKey id;

    @ManyToOne
    @MapsId("userID")
    @JoinColumn(name="userID")
    private User user;

    @ManyToOne
    @MapsId("focusID")
    @JoinColumn(name="focusID")
    private Focus focus;

    private BigDecimal baserating;

    protected rating(){}

    public rating(User user,Focus focus,BigDecimal baserating) {
        this.user = user;
        this.focus = focus;
        this.baserating = baserating;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public Focus getFocus() {
        return focus;
    }

    public void setFocus(Focus focus) {
        this.focus = focus;
    }

    public BigDecimal getBaserating() {
        return baserating;
    }

    public void setBaserating(BigDecimal baserating) {
        this.baserating = baserating;
    }
}

和

@Embeddable
public class ratingKey implements Serializable {

    @Column(name="userID")
    private Long userID;

    @Column(name="focusID")
    private Long focusID;

    protected ratingKey(){}

    public ratingKey(Long userID,Long focusID) {
        this.userID = userID;
        this.focusID = focusID;
    }

    public Long getUserID() {
        return userID;
    }

    public void setUserID(Long userID) {
        this.userID = userID;
    }

    public Long getFocusID() {
        return focusID;
    }

    public void setFocusID(Long focusID) {
        this.focusID = focusID;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        ratingKey ratingKey = (ratingKey) o;
        return Objects.equals(userID,ratingKey.userID) &&
                Objects.equals(focusID,ratingKey.focusID);
    }

    @Override
    public int hashCode() {
        return Objects.hash(userID,focusID);
    }
}

UserBaseratings的表的baserating的默认值为1，这样，如果用户对当前焦点没有评级，则他们的评级应为1。如果用户未进行评级，则会遇到问题一个等级，则该等级的集合为空，而不是每个存在的焦点的等级为1。

用户：

public class User {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Long userID;

    @Column(name = "userHashedPassword")
    private String password;

    @Column(name = "userName")
    private String userName;
    @Column(name = "userEmail")
    private String email;

    //probably being reset
    @Transient
    private List<String> groups = new LinkedList<>();

    @ManyToMany
    @JoinTable(name = "UserRoles",joinColumns = @JoinColumn(
                name = "userID"),inverseJoinColumns = @JoinColumn(
                    name = "roleID"))
    private Set<Role> roles = new HashSet<>();

    @OnetoMany(mappedBy = "user")
    private Set<rating> ratings;

    protected User(){}

    public User(String userHashedPassword,String userName,String email,Set<Role> roles){
        this.password = userHashedPassword;
        this.userName = userName;
        this.email = email;
        this.roles = roles;
    }

    public Long getUserId() {
        return userID;
    }

    public void setId(Long userID) {
        this.userID = userID;
    }

    public String getpassword(){
        return password;
    }

    public void setPassword(String password){
        this.password = password;
    }

    public String getUsername() {
        return userName;
    }

    public void setUsername(String name) {
        this.userName = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public Set<Role> getRoles() {
        return roles;
    }

    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }

    public Set<rating> getratings() {
        return ratings;
    }

    public void setratings(Set<rating> ratings) {
        this.ratings = ratings;
    }
}

重点：

@Entity
public class Focus {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long focusID;

    private String focusCategory;

    private String focusName;

    private String focusExplanation;

    @OnetoMany(mappedBy = "focus")
    Set<rating> ratings;

    //image

    protected Focus(){}

    public Focus(String focusCategory,String focusName,String focusExplanation,Set<rating> ratings){
        this.focusCategory = focusCategory;
        this.focusName = focusName;
        this.focusExplanation = focusExplanation;
        this.ratings = ratings;
    }

    public Long getFocusId() {
        return focusID;
    }

    public void setFocusId(Long focusID) {
        this.focusID = focusID;
    }

    public String getFocusCategory() {
        return focusCategory;
    }

    public void setFocusCategory(String focusCategory) {
        this.focusCategory = focusCategory;
    }

    public String getFocusName() {
        return focusName;
    }

    public void setFocusName(String focusName) {
        this.focusName = focusName;
    }

    public String getFocusExplanation() {
        return focusExplanation;
    }

    public void setFocusExplanation(String focusExplanation) {
        this.focusExplanation = focusExplanation;
    }

    public Set<rating> getratings() {
        return ratings;
    }

    public void setratings(Set<rating> ratings) {
        this.ratings = ratings;
    }
}

我缺少什么，可以使用数据库中存在的每个焦点的默认值填充用户的评分？

编辑：将@PrePersist和@PreUpdate添加到评级实体：

@Entity(name = "UserBaseratings")
public class rating {

    @EmbeddedId
    ratingKey id;

    @ManyToOne
    @MapsId("userID")
    @JoinColumn(name="userID")
    private User user;

    @ManyToOne
    @MapsId("focusID")
    @JoinColumn(name="focusID")
    private Focus focus;

    private BigDecimal baserating;

    protected rating(){}

    public rating(User user,BigDecimal baserating) {
        this.user = user;
        this.focus = focus;
        this.baserating = baserating;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public Focus getFocus() {
        return focus;
    }

    public void setFocus(Focus focus) {
        this.focus = focus;
    }

    public BigDecimal getBaserating() {
        return baserating;
    }

    public void setBaserating(BigDecimal baserating) {
        this.baserating = baserating;
    }

    @PrePersist
    public void prePersist() {
        if(baserating == null) {
            baserating = BigDecimal.ONE;
        }
    }

    @PreUpdate
    public void preUpdate() {
        if(baserating == null) {
            baserating = BigDecimal.ONE;
        }
    }
}

将spring.jpa.hibernate.ddl-auto=从none更改为update也没什么区别。

解决方法

如果使用ORM，则必须显式声明所有默认值。可以通过这种方式完成

@Entity(name = "UserBaseRatings")
public class Rating {

    // ...

    private BigDecimal baseRating = BigDecimal.ONE;

    // ...
}

或使用@PrePersist和@PreUpdate

@Entity(name = "UserBaseRatings")
public class Rating {
    
    // ...
    
    private BigDecimal baseRating;
        
    // ...
    
    @PrePersist
    public void prePersist() {
        if(baseRating == null) {
           baseRating = BigDecimal.ONE;
        }
    }  
    
    @PreUpdate
    public void preUpdate() {
        if(baseRating == null) {
           baseRating = BigDecimal.ONE;
        }
    }    
}

jpa spring spring-boot spring-data-jpa spring-mvc