解决方法
AFAIK在普通的Ruby中没有这样的东西.您可以像这样创建自己的：
class NilClass
def blank?
true
end
end
class String
def blank?
self.strip.empty?
end
end
这适用于nil.blank？和a_string.blank？你可以为真/假和一般对象扩展这个(就像rails一样)：
class FalseClass
def blank?
true
end
end
class TrueClass
def blank?
false
end
end
class Object
def blank?
respond_to?(:empty?) ? empty? : !self
end
end
参考文献：
https://github.com/rails/rails/blob/2a371368c91789a4d689d6a84eb20b238c37678a/activesupport/lib/active_support/core_ext/object/blank.rb#L57
https://github.com/rails/rails/blob/2a371368c91789a4d689d6a84eb20b238c37678a/activesupport/lib/active_support/core_ext/object/blank.rb#L67
https://github.com/rails/rails/blob/2a371368c91789a4d689d6a84eb20b238c37678a/activesupport/lib/active_support/core_ext/object/blank.rb#L14
https://github.com/rails/rails/blob/2a371368c91789a4d689d6a84eb20b238c37678a/activesupport/lib/active_support/core_ext/object/blank.rb#L47
这是String.blank？实施应该比前一个更有效：