Spring 引导：存储枚举 Integer 常量值到 MySQL 数据库表

Question

I'm a beginner in Spring Boot and Java and having following issues while trying to store VoteType Enum Constant value in the database as Integer.

1. In MySQL DB, value for DOWNVOTE and UPVOTE is being stored as 0 and 1 respectively instead of -1 and 1.
2. I am unable to print the Integer Constant value of DOWNVOTE and UPVOTE. I've tried to do System.out.println(VoteType.UPVOTE.ordinal()), but it still prints UPVOTE instead of it's Integer value ie 1

Here's my code:

VoteType.java

public enum VoteType {
     DOWNVOTE(-1), UPVOTE(1);

    private final int direction;

    VoteType(int direction) {
        this.direction= direction;
    }
    
    public Integer getDirection() {
        return direction;
    }
    
}

VoteService.java

@Service
@Transactional
@AllArgsConstructor
public class VoteService {
    
    private final VoteRepository voteRepository;
    private final PostRepository postRepository;
    private final AuthService authService;

    @Transactional
    public void vote(VoteDto voteDto) {
        Post post = postRepository.findById(voteDto.getPostId())
                .orElseThrow(() -> new PostNotFoundException("Post Not Found with ID - " + voteDto.getPostId()));
        Optional<Vote> voteByPostAndUser = 
                voteRepository.findTopByPostAndUserOrderByIdDesc(post, 
                                                                 authService.getCurrentUser());
        if (voteByPostAndUser.isPresent() &&
                voteByPostAndUser.get().getType()
                        .equals(voteDto.getVoteType())) {
            throw new MyRedditException("You have already "
                    + voteDto.getVoteType() + "'d for this post");
        }
        if (UPVOTE.equals(voteDto.getVoteType())) {
            post.setVoteCount(post.getVoteCount() + 1);
        } else {
            post.setVoteCount(post.getVoteCount() - 1);
        }

        voteRepository.save(mapDtoToVote(voteDto, post));

        postRepository.save(post);
    }

    private Vote mapDtoToVote(VoteDto voteDto, Post post) {
        return Vote.builder()
                .type(voteDto.getVoteType())
                .post(post)
                .user(authService.getCurrentUser())
                .build();
    }
}

VoteController.java

@RestController
@RequestMapping("/api/votes/")
@AllArgsConstructor
public class VoteController {
    private final VoteService voteService;
    
    @PostMapping
    public ResponseEntity<Void> save(@RequestBody VoteDto voteDto){
        voteService.vote(voteDto);
        return new ResponseEntity<>(HttpStatus.CREATED);
    }

}

VoteDto.java

@AllArgsConstructor
@NoArgsConstructor
@Data
public class VoteDto {
    private VoteType voteType;
    private Long postId;
}

Vote.java

@Entity
@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
@Table(name = "vote")
public class Vote {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @Column(name = "type")
    private VoteType type;  
    
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "user_id")
    private User user;
    
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "post_id")
    private Post post;
    
}

Screenshot of Vote Table where Type is getting stored as 0 and 1 instead of -1 and 1 for DOWNVOTE and UPVOTE respectively.

Please let me know if more detail is needed to answer this question. Thanks.

Answer 1

Simply define type as Integer and translate to enum in get/set methods.

@Column(name = "type")
private Integer type;  

public VoteType getType() {
    return VoteType.fromValue(this.type);
}

public void setType(VoteType type) {
    this.type = type.getValue();
}