java - [java.lang.ArrayIndexOutOfBoundsException : Index 2 out of bounds for length 2]

Question

我知道有人问过这个问题 here但我找不到解决方案。所以answer在该问题中解释问题:

The exception happens at EnumJavaTypeDescriptor.fromOrdinal. So my guess is that your role_id value in the database column is 2.

But there are only two values in the UserType enum: ADMIN and USER. ADMIN's ordinal is 0, and USER's ordinal is 1. So if your row contains 2 in the user_type column, it's an invalid ordinal for the UserType enum.

在数据库中，我有两个值 1 和 2 代表两个字符串“black”和“white”，所以我无法将它们从 1 和 2 更改为 0 和 1。所以我应该在我的 java 代码中处理它，所以我尝试了这个但我不断收到相同的错误

public enum TypeColor {
    black(1),
    white(2);

    private int val;

    private TypeColor(int val) {
        this.val = val;
    }
}

更新

这是使用该枚举的实体

@Entity
@Table(name = "BOOKS")
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class Book implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequenceGenerator")
    @SequenceGenerator(name = "sequenceGenerator")
    @Column(name = "id")
    private Long id;
   
   private TypeColor typeColor; 

    //other attributes, getters, setters
    
}

在 Controller 中，当我尝试获取所有书籍时，我收到了该错误(在标题中)

@GetMapping("/books")
    public ResponseEntity<List<Book>> getAllBooks(@org.springdoc.api.annotations.ParameterObject Pageable pageable) {
        log.debug("REST request to get a page of Books");
        Page<Rdv> page = bookRepository.findAll(pageable);
        HttpHeaders headers = PaginationUtil.generatePaginationHttpHeaders(ServletUriComponentsBuilder.fromCurrentRequest(), page);
        return ResponseEntity.ok().headers(headers).body(page.getContent());
    }

Answer 1

要将 int 转换为枚举(其中该 int 不是枚举常量的ordinal())，您需要一个查找函数。您已经将整数值分配给常量，因此剩下的就是查找本身:

public enum TypeColor {
    black(1),
    white(2);

    private int val;

    private TypeColor(int val) {
        this.val = val;
    }

    static TypeColor lookup(int v) {
        for(TypeColor t:values()) {
            if(t.val == v) {
                return t;
            }
        }
        return null; //or throw an Exception
    }
}