如何为Kryo序列化器注册许多类？ （例如，包中的所有类）

Question

Registering all classes for efficient Kryo Serialization takes a lot of time. So I'm trying to make a Kryo Registrator that takes package as parameter (in Java or Scala). I'm wondering what is the easiest way to do so? (Of course, with reflection, but better with existing libraries) Thanks a lot for your help.

Answer 1

It's not a custom Registrator (though you could doubtless turn it into one), but you could use the Reflections library to obtain a Set of all the classes that extend Object in the package of interest. Then simply register each member of the set.

Reflections reflections = new Reflections(new ConfigurationBuilder()
        .setUrls(ClasspathHelper.forPackage("your.package"))
        .setScanners(new SubTypesScanner(false)));
Set<Class<? extends Object>> types = reflections.getSubTypesOf(Object.class);
for (Class c : types) {
    kryoInstance.register(c.getClass());
}

Note that this will register EVERY class that extends Object (including anonymous, inner, etc). You'd probably be better served by either using the annotation capabilities of the library to restrict what you register to those classes you really want - unless that's all that's in the specified package!