JAVA-无法解析方法“.equals（）”[重复]

Question

我正在REST API中执行一个方法，您可以通过其ID获取出版物上的注释。CommentServiceImplementation中出现错误，因为它无法解析方法等于（long）

评论服务实施

@Override
public CommentDto getCommentById(long publicationId, long commentId) {
    Publication publication = publicationRepository.findById(publicationId)
            .orElseThrow(() -> new ResourceNotFoundException("Publication", "id", publicationId));

    //once found the publication we find the comment
    Comment comment = commentRepository.findById(commentId)
            .orElseThrow(() -> new ResourceNotFoundException("Comment", "id", commentId));

    if (comment.getPublication().getId().equals(publication.getId())) {
        throw new BlogAppException(HttpStatus.BAD_REQUEST, "The comment does not belong to the publication")
    }
    return mapDTO(comment);
}

我首先找到了出版物。然后我找到了评论。最后，如果与发布相关联的注释ID与发布的ID不同，则该注释不属于所述发布。如果是，我会将注释作为DTO返回。据我所知，问题一定是出版物。getId（）返回一个长的和注释。getPublication（）。getId（）的静态类型不提供等于（长）。但看不出我的错误在哪里（我有点跟着别人的教程，他们没有错）。

出版物类

@Entity
@AllArgsConstructor @NoArgsConstructor @ToString
@Table(name = "publications", uniqueConstraints = {@UniqueConstraint(columnNames = {"title"})})
@Getter @Setter
public class Publication {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;

    @Column(name = "title", nullable = false)
    private String title;
    @Column(name = "description", nullable = false)
    private String description;
    @Column(name = "content", nullable = false)
    private String content;

    @OneToMany(mappedBy = "publication", cascade = CascadeType.ALL, orphanRemoval = true)
    private Set<Comment> comments = new HashSet<>();

注释类

@Entity
@Table(name = "comments")
@Getter@Setter
@AllArgsConstructor
@NoArgsConstructor
public class Comment {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;

    private String name;
    private String email;
    private String body;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "publications_id", nullable = false)
    private Publication publication;

注释到类

@Getter@Setter@NoArgsConstructor
public class CommentDto {

    private long id;
    private String name;
    private String email;
    private String body;
}

CommentService类公共接口CommentService{

public CommentDto createComment(Long publicationId, CommentDto commentDto);

public List<CommentDto> getCommentByPublicationID(long publicationId);

public CommentDto getCommentById(long publicationId, long commentId);

Answer 1

<代码>。equals（）仅用于比较对象。您正在尝试比较长的，这是您需要使用比较的八种基本类型之一。Java中的八种基本类型是int、byte、short、long、float、double、boolean和char。

if (comment.getPublication().getId() == publication.getId()) {