要让你的类方法变得私有，你需要使用 private_class_method :method_name 或者把你的私有类方法放到class << self block 中：

class Foo  class << self    private        def bar      puts 'Class method called'    end      end  def self.baz    puts 'Another class method called'  end  private_class_method :bazendFoo.bar # => NoMethodError: private method `bar' called for Foo:ClassFoo.baz # => NoMethodError: private method `baz' called for Foo:Class