chinabugotech/hutool · error · ConvertException

Can not convert {} to {}

Error message

Can not convert {} to {}

What it means

EnumConverter.convertInternal tries EnumItem conversion, then a static valueOf-like method on the enum, then Enum.valueOf. If none yields a constant it throws ConvertException with the value and enum class.

Source

Thrown at hutool-core/src/main/java/cn/hutool/core/convert/impl/EnumConverter.java:53

	 * @param enumClass 转换成的目标Enum类
	 */
	public EnumConverter(Class enumClass) {
		this.enumClass = enumClass;
	}

	@Override
	protected Object convertInternal(Object value) {
		Enum enumValue = tryConvertEnum(value, this.enumClass);
		if (enumValue == null && !(value instanceof String)) {
			// 最后尝试先将value转String，再valueOf转换
			enumValue = Enum.valueOf(this.enumClass, convertToStr(value));
		}

		if (null != enumValue) {
			return enumValue;
		}

		throw new ConvertException("Can not convert {} to {}", value, this.enumClass);
	}

	@Override
	public Class getTargetType() {
		return this.enumClass;
	}

	/**
	 * 尝试转换，转换规则为：
	 * <ul>
	 *     <li>如果实现{@link EnumItem}接口，则调用fromInt或fromStr转换</li>
	 *     <li>找到类似转换的静态方法调用实现转换且优先使用</li>
	 *     <li>约定枚举类应该提供 valueOf(String) 和 valueOf(Integer)用于转换</li>
	 *     <li>oriInt /name 转换托底</li>
	 * </ul>
	 *
	 * @param value     被转换的值
	 * @param enumClass enum类

View on GitHub (pinned to 8870454b2a)

Solutions

1. Validate the value against EnumUtil.getNames(enumClass) / fromString before converting.
2. Pass a defaultValue so AbstractConverter returns it instead of throwing.
3. Normalize input (trim, uppercase) to match constant names, or have your enum implement EnumItem for int/string mapping.

Example fix

// before
Color c = Convert.convert(userInput, Color.class);

// after - validate then convert
String name = userInput.trim().toUpperCase();
if (!EnumUtil.getNames(Color.class).contains(name)) {
    return Color.DEFAULT;
}
Color c = Convert.convert(name, Color.class);

if (value instanceof String) {
    String name = ((String) value).trim().toUpperCase();
    if (!EnumUtil.getNames(enumClass).contains(name)) {
        return defaultValue; // or throw a controlled error
    }
}
Convert.convert(value, enumClass);

try {
    return Convert.convert(value, enumClass);
} catch (ConvertException e) {
    if (e.getMessage().startsWith("Can not convert") && e.getMessage().contains(enumClass.getSimpleName())) {
        return defaultValue;
    }
    throw e;
}

When it happens

Trigger: Calling Convert.convert("BLUE", Color.class) when Color has no constant named BLUE; converting an int that matches no enum ordinal/EnumItem int code; case mismatch ("blue" vs "BLUE").

Common situations: User input to an enum where the value does not exist; external data using a different casing or synonym; numeric value out of the enum's range.

Related errors

• Bad number '{}{}' at: {}
• Unknown unit '{}' at: {}
• Video URI is empty
• File not found!
• Base58 checksum is invalid

AI-assisted analysis of chinabugotech/hutool@8870454b2a (2026-08-14). Data as JSON: /api/errors/475a832b0858bcc7. Report an issue: GitHub.