java-----内部类

内部类概述：

public class Outer {

    private int num=10;

        public class Inter {

            public void show() {
                System.out.println(num);
            }
        }

        public void method() {
            Inter i=new Inter();
            i.show();
        }


}

匿名内部类：

public interface Inter {
    void show();
}

public class Outer {
    public void methed() {
  

        //多次调用的写法如下
        Inter i=new Inter(){
            @Override
            public void show() {
                System.out.println("匿名内部类");
            }
        };
        i.show();
        i.show();
        i.show();


    }
}

public class OuterDemo {
    public static void main(String[] args) {
        Outer o=new Outer();
        o.methed();
    }
}

局部内部类：

public class Outer {

    private int num=10;

    public void method(){
        int num2=20;
      class Inner{
            public void show() {
                System.out.println(num);
                System.out.println(num2);
            }
        }
            Inner i=new Inner();
                 i.show();
    }

}

public class OuterDemo {
    public static void main(String[] args) {
        Outer o=new Outer();
        o.method();
    }
}

成员内部类：

public class Outer {

    private int num =10;

    private class Inter{
        public void show() {
            System.out.println(num);
        }
    }

    public void method() {
        Inter i=new Inter();
        i.show();
    }
}

public class InterDemo {
    public static void main(String[] args) {
        //创建内部类对象，并调用方法
        Outer.Inter oi=new Outer().new Inter();
        oi.show();

        Outer o=new Outer();
        o.method();
    }
}