java.lang.IllegalArgumentException : No enum constant found

Question

我有这个枚举，我想用它来设置不同的状态:

@Enumerated(EnumType.STRING)
@Column(name = "status", length = 20)
private OnboardingTaskStatus status; 

public enum OnboardingTaskStatus {
    NEW,
    IN_PROGRESS,
    DISABLED,
}

当我尝试构建搜索规范时，我得到了这个:

public Page<OnboardingTaskDto> findOnboardingTasks(OnboardingTaskSearchParams params, Pageable pageable){
        Specification<OnboardingTasks> spec = (root, query, cb) -> {
            List<Predicate> predicates = new ArrayList<>();
            if (params.getStatus() != null) {
                predicates.add(cb.equal(root.get("status"), params.getStatus()));
            }
            return cb.and(predicates.toArray(new Predicate[predicates.size()]));
        };
        return onboardingTasksService.findAll(spec, pageable).map(onboardingMapper::taskToTaskDTO);
    }

@Getter
@Setter
public class OnboardingTaskSearchParams {
    private String title;
    private String status;

    private LocalDateTime createdAt;
    private LocalDateTime updatedAt;
}

我尝试将状态更新为该文件:

predicates.add(cb.equal(root.get("status"), OnboardingTaskStatus.valueOf(params.getStatus())));

但我得到错误:

OnboardingTaskStatus.2769df0841; nested exception is java.lang.IllegalArgumentException: No enum constant OnboardingTaskStatus.2769df0841] with root causejava.lang.IllegalArgumentException: No enum constant OnboardingTaskStatus.2769df0841

如果找不到值，您是否知道实现 Enum 搜索而不抛出错误的正确方法是什么？

Answer 1

您可以在 Enum 中引入静态方法检查给定字符串是否正确 Enum值(value)。像这样的东西，

enum OnBoardingTaskStatus {
    NEW,
    IN_PROGRESS,
    DISABLED;

    public static Optional<OnBoardingTaskStatus> check(String val) {
        try { return Optional.of(OnBoardingTaskStatus.valueOf(val)); }
        catch (Exception e) {/* do nothing */}
        return Optional.empty();
    }
}

注意这里我返回了一个 Optional那你可以换 findOnboardingTasks方法如下，

public Page<OnboardingTaskDto> findOnboardingTasks(OnboardingTaskSearchParams params, Pageable pageable) {
    Specification<OnboardingTasks> spec = (root, query, cb) -> {
        List<Predicate> predicates = new ArrayList<>();
        predicates.add(cb.notEqual(cb.literal(1), 1));

        OnBoardingTaskStatus.check(params.getStatus())
                .ifPresent(e -> predicates.add(cb.equal(root.get("status"), e)));

        return cb.or(predicates.toArray(new Predicate[]{}));
    };
    return onboardingTasksService.findAll(spec, pageable).map(onboardingMapper::taskToTaskDTO);
}