Ruby面向对象编程如何应用

面向对象编程（Object-Oriented Programming，OOP）是一种编程范式，它使用“对象”来表示现实世界中的事物，通过封装、继承和多态等特性来实现代码的复用和模块化。在Ruby中，面向对象编程的应用非常广泛，以下是一些常见的应用场景：

1. 封装（Encapsulation）

封装是将对象的属性和方法隐藏起来，只暴露必要的接口。这样可以保护对象内部的状态不被外部直接修改，提高代码的安全性和可维护性。

class Car
  attr_reader :make, :model, :year

  def initialize(make, model, year)
    @make = make
    @model = model
    @year = year
  end

  def drive
    puts "Driving the #{@make} #{@model}..."
  end
end

car = Car.new("Toyota", "Corolla", 2020)
car.drive

2. 继承（Inheritance）

继承允许一个类（子类）继承另一个类（父类）的属性和方法。子类可以重写或扩展父类的方法，实现代码的复用。

class Vehicle
  attr_accessor :make, :model, :year

  def initialize(make, model, year)
    @make = make
    @model = model
    @year = year
  end

  def drive
    puts "Driving..."
  end
end

class Car < Vehicle
  def drive
    puts "Driving the #{@make} #{@model}..."
  end
end

bike = Vehicle.new("Honda", "CBR", 2021)
bike.drive

car = Car.new("Toyota", "Corolla", 2020)
car.drive

3. 多态（Polymorphism）

多态是指不同类的对象可以使用相同的接口。通过多态，可以在运行时根据对象的实际类型调用相应的方法，提高代码的灵活性和可扩展性。

class Vehicle
  attr_accessor :make, :model, :year

  def initialize(make, model, year)
    @make = make
    @model = model
    @year = year
  end

  def drive
    puts "Driving..."
  end
end

class Car < Vehicle
  def drive
    puts "Driving the #{@make} #{@model}..."
  end
end

class Motorcycle < Vehicle
  def drive
    puts "Riding the #{@make} #{@model}..."
  end
end

vehicles = [Car.new("Toyota", "Corolla", 2020), Motorcycle.new("Honda", "CBR", 2021)]

vehicles.each do |vehicle|
  vehicle.drive
end

4. 模块（Modules）

模块是一种代码复用的方式，可以将一组相关的函数和方法封装在一个模块中，然后在其他类中通过include关键字引入。

module Drivable
  def drive
    puts "Driving..."
  end
end

class Vehicle
  include Drivable

  attr_accessor :make, :model, :year

  def initialize(make, model, year)
    @make = make
    @model = model
    @year = year
  end
end

car = Vehicle.new("Toyota", "Corolla", 2020)
car.drive

5. 抽象类（Abstract Classes）

抽象类是不能实例化的类，通常用于定义一些通用的方法和属性，供子类实现。

class Vehicle
  attr_accessor :make, :model, :year

  def initialize(make, model, year)
    @make = make
    @model = model
    @year = year
  end

  def drive
    raise NotImplementedError, "This method must be overridden in subclass"
  end
end

class Car < Vehicle
  def drive
    puts "Driving the #{@make} #{@model}..."
  end
end

class Motorcycle < Vehicle
  def drive
    puts "Riding the #{@make} #{@model}..."
  end
end

vehicles = [Car.new("Toyota", "Corolla", 2020), Motorcycle.new("Honda", "CBR", 2021)]

vehicles.each do |vehicle|
  vehicle.drive
end

通过这些面向对象编程的特性，Ruby可以编写出结构清晰、易于维护和扩展的代码。