java reflection to create field/value hashmap

Question

I need to create a Hashmap of field/values contained in an Entity, so I can can use them to replace them in a String containing tags with the field names.

I have this code:

public static String replaceTags(String message, Map<String, String> tags) ...

Which replaces all tags found in message for the equivalent values in tags, but in order to build the Map table I need to take "any" Entity and be able to create a Map from the Entity. So, how could I make that possible? to get a routine where I send the Entity and get as return a Map with all the fields and values.

public static Map<String, String> getMapFromEntity(Object entity){
    Map<String, String> map = new HashMap<String, String>();

    ...?????

    return map;
}

I know I could use reflection and this is the only approach I have found to get this done, but is there any other way to accomplish the same?, I mean a more efficient way.

Thanks.

Answer 1

If all you want to get out of this is a map, why not use a literary like Jackson, then you can simply convert it like this Map map = new ObjectMapper().convertValue(object, Map.class);

Answer 2

    Field[] fields = entity.getClass().getFields();
    Map<String, String> map = new HashMap<String, String>();
    for(Field f : fields)
            map.put(f.getName(),(String) f.get(entity));

O, and your entity should be an object of your class, not your class itself. If your fields are private and you have getters for them, you should use getMethods() and check if method name starts with "get" prefix.Like this:

    Method[] methods = entity.getClass().getMethods();
    Map<String, String> map = new HashMap<String, String>();
    for(Method m : methods)
    {
        if(m.getName().startsWith("get"))
        {
            String value = (String) m.invoke(entity);
            map.put(m.getName().substring(3), value);
        }
    }