Java内部类和静态嵌套类 | Java内部类和静态嵌套类

本文介绍了Java内部类和静态嵌套类的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

Java中内部类和静态嵌套类之间的主要区别是什么？设计/实现是否在选择其中一个中起作用？

What is the main difference between an inner class and a static nested class in Java? Does design / implementation play a role in choosing one of these?

推荐答案

来自：

使用封闭的类名访问静态嵌套类：

Static nested classes are accessed using the enclosing class name:

OuterClass.StaticNestedClass

例如，为静态创建对象嵌套类，使用以下语法：

For example, to create an object for the static nested class, use this syntax:

OuterClass.StaticNestedClass nestedObject = new OuterClass.StaticNestedClass();

作为内部类实例的对象存在于外部类的实例中。考虑以下类：

Objects that are instances of an inner class exist within an instance of the outer class. Consider the following classes:

class OuterClass {
    ...
    class InnerClass {
        ...
    }
}

InnerClass的一个实例只能存在于OuterClass的一个实例，可以直接访问其封闭实例的方法和字段。

An instance of InnerClass can exist only within an instance of OuterClass and has direct access to the methods and fields of its enclosing instance.

要实例化内部类，必须首先实例化外部类。然后，使用以下语法在外部对象中创建内部对象：

To instantiate an inner class, you must first instantiate the outer class. Then, create the inner object within the outer object with this syntax:

OuterClass.InnerClass innerObject = outerObject.new InnerClass();

参见：

为了完整性，请注意还有这样的事情：

For completeness note that there is also such a thing as an inner class without an enclosing instance:

class A {
  int t() { return 1; }
  static A a =  new A() { int t() { return 2; } };
}

此处，新A（）{... } 是在静态上下文中定义的内部类，并且没有封闭的实例。

Here, new A() { ... } is an inner class defined in a static context and does not have an enclosing instance.

这篇关于Java内部类和静态嵌套类的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！