今天看到很多程序员写的代码，老是在enum与string之间来回转换，自己也不确定struts2能否进行enum的类型转换，struts2的文档说不支持enum的自动转换，通过阅读struts2的DefaultTypeConverter源代码发现是可以的，主要集中在convertValue方法

    public Object convertValue(Object value, Class toType) {
        Object result = null;

        if (value != null) {
            /* If array -> array then convert components of array individually */
            if (value.getClass().isArray() && toType.isArray()) {
                Class componentType = toType.getComponentType();

                result = Array.newInstance(componentType, Array
                        .getLength(value));
                for (int i = 0, icount = Array.getLength(value); i < icount; i++) {
                    Array.set(result, i, convertValue(Array.get(value, i),
                            componentType));
                }
            } else {
                if ((toType == Integer.class) || (toType == Integer.TYPE))
                    result = Integer.valueOf((int) longValue(value));
                if ((toType == Double.class) || (toType == Double.TYPE))
                    result = new Double(doubleValue(value));
                if ((toType == Boolean.class) || (toType == Boolean.TYPE))
                    result = booleanValue(value) ? Boolean.TRUE : Boolean.FALSE;
                if ((toType == Byte.class) || (toType == Byte.TYPE))
                    result = Byte.valueOf((byte) longValue(value));
                if ((toType == Character.class) || (toType == Character.TYPE))
                    result = new Character((char) longValue(value));
                if ((toType == Short.class) || (toType == Short.TYPE))
                    result = Short.valueOf((short) longValue(value));
                if ((toType == Long.class) || (toType == Long.TYPE))
                    result = Long.valueOf(longValue(value));
                if ((toType == Float.class) || (toType == Float.TYPE))
                    result = new Float(doubleValue(value));
                if (toType == BigInteger.class)
                    result = bigIntValue(value);
                if (toType == BigDecimal.class)
                    result = bigDecValue(value);
                if (toType == String.class)
                    result = stringValue(value);
                if (Enum.class.isAssignableFrom(toType))
                    result = enumValue((Class)toType, value);
            }
        } else {
            if (toType.isPrimitive()) {
                result = primitiveDefaults.get(toType);
            }
        }
        return result;
    }