封装和抽象之间的确切区别是什么?
当前回答
封装是将复杂性包裹在一个胶囊中,即类&因此封装… 抽象是一个对象区别于其他对象的特征。
抽象可以通过使具有一个或多个抽象方法的类抽象来实现。它只是一个特性,应该由扩展它的类来实现。 例如,当你发明/设计一辆汽车时,你定义了一个特征,比如汽车应该有4个门、刹车、方向盘等,所以任何使用这种设计的人都应该包括这些特征。实现并不是抽象的首要部分。它只会定义应该包含的特征。
Encapsulation is achieved keeping data and the behaviour in one capsule that is class & by making use of access modifiers like public, private, protected along with inheritance, aggregation or composition. So you only show only required things, that too, only to the extent you want to show. i.e. public, protected, friendly & private ka funda…… e.g. GM decides to use the abstracted design of car above. But they have various products having the same characteristics & doing almost same functionality. So they write a class which extends the above abstract class. It says how gear box should work, how break should work, how steering wheel should work. Then all the products just use this common functionality. They need not know how the gear box works or break works or steering wheal works. Indivisual product can surely have more features like a/c or auto lock etc…..
两者都很强大;但是使用抽象需要比封装更多的技能,没有抽象,更大的应用程序/产品就无法生存。
其他回答
封装意味着隐藏数据,比如使用getter和setter等。
抽象意味着-隐藏实现使用抽象类和接口等。
封装是将复杂性包裹在一个胶囊中,即类&因此封装… 抽象是一个对象区别于其他对象的特征。
抽象可以通过使具有一个或多个抽象方法的类抽象来实现。它只是一个特性,应该由扩展它的类来实现。 例如,当你发明/设计一辆汽车时,你定义了一个特征,比如汽车应该有4个门、刹车、方向盘等,所以任何使用这种设计的人都应该包括这些特征。实现并不是抽象的首要部分。它只会定义应该包含的特征。
Encapsulation is achieved keeping data and the behaviour in one capsule that is class & by making use of access modifiers like public, private, protected along with inheritance, aggregation or composition. So you only show only required things, that too, only to the extent you want to show. i.e. public, protected, friendly & private ka funda…… e.g. GM decides to use the abstracted design of car above. But they have various products having the same characteristics & doing almost same functionality. So they write a class which extends the above abstract class. It says how gear box should work, how break should work, how steering wheel should work. Then all the products just use this common functionality. They need not know how the gear box works or break works or steering wheal works. Indivisual product can surely have more features like a/c or auto lock etc…..
两者都很强大;但是使用抽象需要比封装更多的技能,没有抽象,更大的应用程序/产品就无法生存。
封装隐藏了实现细节,这些细节可能是通用的,也可能不是专门的行为。
抽象提供了一种泛化(例如,在一组行为之上)。
这里有一个很好的阅读:抽象、封装和信息隐藏,作者是Object Agency的Edward V. Berard。
上面提供了很多很好的答案,但我将在这里介绍我的(Java)观点。
数据封装简单地说就是包装和控制类中逻辑分组数据的访问。它通常与另一个关键字-数据隐藏相关联。这是在Java中使用访问修饰符实现的。
一个简单的例子是定义一个私有变量,并使用getter和setter方法访问它,或者将一个方法设置为私有,因为它只在类中使用。用户不需要知道这些方法和变量。
注意:不要误解封装只是关于数据隐藏。当我们说封装时,重点应该是将相关数据和行为分组、打包或捆绑在一起。
另一方面,数据抽象是泛化的概念,这样底层的复杂逻辑就不会暴露给用户。在Java中,这是通过使用接口和抽象类实现的。
的例子,
Lets say we have an interface Animal and it has a function makeSound(). There are two concrete classes Dog and Cat that implement this interface. These concrete classes have separate implementations of makeSound() function. Now lets say we have a animal(We get this from some external module). All user knows is that the object that it is receiving is some Animal and it is the users responsibility to print the animal sound. One brute force way is to check the object received to identify it's type, then typecast it to that Animal type and then call makeSound() on it. But a neater way is to abstracts thing out. Use Animal as a polymorphic reference and call makeSound() on it. At runtime depending on what the real Object type is proper function will be invoked.
详情请点击这里。
复杂的逻辑是在电路板中,封装在一个触摸板中,并提供了一个漂亮的界面(按钮)来将其抽象给用户。
附注:以上链接是我的个人博客。
简而言之:
抽象是一种帮助我们识别哪些特定信息是必要的,哪些信息应该隐藏的技术。
因此,封装是一种以隐藏对象的细节和实现细节的方式封装信息的技术。