hoge

test.rb

require 'json'

class Hoge
  def initialize
    @a=1
    @b='hoge'
    @c={:a => 1}
  end

  def to_json
    h = { }
    self.instance_variables.each do |v|
      h[v] = self.instance_variable_get(v)
    end
    h.to_json
  end
end  


hoge = Hoge.new
p hoge.to_json