> For the complete documentation index, see [llms.txt](https://yubin551.gitbook.io/java-note/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yubin551.gitbook.io/java-note/basic-object-oriented/accessobjectfieldmethod.md).

# 存取物件的欄位、方法

> 我們知道物件有屬性有方法，但該如何存取及使用呢？

透過『點』運算子(dot operator)，就可以存取到物件的屬性、呼叫物件的方法。

```java
class Human{  //習慣上類別名稱都會字首大寫
  String name;
  int age;
  int height;
  void eat(){
    System.out.println("eating");
  }
  void sleep(){
    System.out.println("Zzz");
  }
}//end of class Human
```

上面是一個名叫Human的class，

定義的屬性有：字串(String)型態的姓名(name)、整數(int)型態的年齡(age)、身高(height)，

定義的方法有：eat()會印出"eating"、sleep()會印出"Zzz"兩個方法。

現在在一個我們自己測試用的類別中，利用Human類別產生物件。

```java
class Test{
  public static void main(String[] args){
    Human h1 = new Human();
    h1.name = "小木";
    h1.age = 22;
    h1.height = 178;
    System.out.println( h1.name );
    h1.eat();
  }
}//end of class Test
```

執行結果：

```
小木
eating
```

沒錯，就是透過 『 . 』去作存取呼叫。

但要記住，不是所有屬性方法都可以呼叫的到，物件導向有一個重要特性叫作『封裝(Encapsulation)』，設計該類別的工程師不會希望你可以碰到所有的資訊，他只會提供他想公開給你的屬性或方法，只有那些方法才能用點運算子存取到，詳細說明會在『修飾子』的部份介紹。


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