java内部类的分类

一、静态内部类

public class Out {
    private static String name;
    private int age;

    public static class In{
        private int age;
        public void sayHello(){
            
            System.out.println("my name is : "+name);
            //--编译报错---
            //System.out.println("my age is :"+ age);
        }
    }
}
public static void main(String [] args){
    Out.In innerClass = new Out.In();
    innerClass.sayHello();
}

二、成员内部类

public class Out {
    private String name;

    public void showName(){
        System.out.println("my name is : "+name);
    }

    public class In{
        public void sayHello(){
            System.out.println(name);
            Out.this.showName();
        }
    }
}
public static void main(String [] args){
    Out out = new Out();
    Out.In in = out.new In();
    in.sayHello();
}

三、方法内部类

public class Out {
    private String name;

    public void sayHello(){
        class In{
            public void showName(){
                System.out.println("my name is : "+name);
            }
        }

        In in = new In();
        in.showName();
    }
}

四、匿名内部类

//首先定义一个普通类
public class Out {
    private String name;

    private void sayHello(){
        System.out.println("my name is :" + name);
    }
}

//定义和使用一个匿名内部类
public static void main(String [] args){
    Out out = new Out(){
        @Override
        public void sayHello(){
            System.out.println("my name is cyy");
        }
        public void showName(){
            System.out.println("hello single");
        }
    };
    out.sayHello();
}