java - Spring 验证失败时枚举字段上的自定义错误消息

Question

我的 Spring DTO 中有一个枚举字段，我在 @RestController 中使用它。我希望在验证此枚举字段失败时创建自定义错误消息:

public class ConversionInputDto {

    // validation annotations
    private BigDecimal sourceAmount;

    // enum field
    @NotNull(message = ERROR_EMPTY_VALUE)
    private CurrencyFormat targetCurrency;

    // no-args constructor and getters
} 

接收字符串形式的输入并生成 custom annotation在我的情况下似乎有点矫枉过正，而我知道的另一种选择是通过 @ControllerAdvise 捕获所有 InvalidFormatException 错误并为它们返回相同的错误(因此，用户提交例如，数字属性的字符串输入将得到相同的错误消息):

@ExceptionHandler(InvalidFormatException.class)
public void handleInvalidEnumAndAllOtherInvalidConversions(HttpServletResponse response) throws IOException {
    response.sendError(HttpStatus.BAD_REQUEST.value(), ERROR_MESSAGE);
}

当前的默认验证错误太长，我想让它更加用户友好，例如“无效的货币格式值。请选择......”:

"Invalid JSON input: Cannot deserialize value of type com.foreignexchange.utilities.CurrencyFormat from String \"test\": not one of the values accepted for Enum class: [AUD, PLN, MXN, USD, CAD]; nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type com.foreignexchange.utilities.CurrencyFormat from String \"test\": not one of the values accepted for Enum class: [AUD, PLN, MXN, USD, CAD]\n at [Source: (PushbackInputStream); line: 3, column: 20] (through reference chain: com.foreignexchange.models.ConversionInputDto[\"targetCurrency\"])",

有没有一种优雅的方法来解决这个问题？也许在 @ExceptionHandler 中使用一些额外的逻辑来检查哪个字段验证失败？

Answer 1

感谢这些评论，我找到了一个解决方案，使用 isAssignableFrom() 为失败的枚举验证提供自定义错误消息:

@ExceptionHandler(InvalidFormatException.class)
public void handleOfflineBankApi(HttpServletResponse response, InvalidFormatException ex) throws IOException {
    if (ex.getTargetType().isAssignableFrom(CurrencyFormat.class)) {
        response.sendError(HttpStatus.BAD_REQUEST.value(), Constants.ERROR_INVALID_CURRENCY_FORMAT);
    } else {
        response.sendError(HttpStatus.BAD_REQUEST.value(), ex.getMessage());
    }
}