在DbForumFactory.java里面
Class c = Class.forName(className);
// Attempt to instantiate the UserManager implementation with a
// DbForumFactory as a paramater.
Class [] params = new Class [] { this.getClass() };
Constructor constructor = c.getConstructor(params);
// Intantiate the gateway object. We assume that
userManager = (UserManager)constructor.newInstance(
new Object[] { this });
}
上面几行代码怎么理解？谢谢