Java内部类介绍

public class InnerClassTest {
    public class FirstInnerClass{
        
    }
}

public class InnerClassTest {
    private int age = 10;
    public class FirstInnerClass{
        int age = 20;
        public void test(){
            int age = 30;
            System.out.println(InnerClassTest.this.age);
            System.out.println(FirstInnerClass.this.age);
            System.out.println(age);
        }
    }

    public static void main(String[] args) {
        InnerClassTest.FirstInnerClass innerClass = new InnerClassTest().new FirstInnerClass();
        innerClass.test();
    }
}

public class InnerClassTest {
    public static class FirstInnerClass{
        
    }
}

public class InnerClassTest {
    private int age = 10;
    public static class FirstInnerClass{
        int age = 20;
        public void test(){
            int age = 30;
            //System.out.println(InnerClassTest.this.age); 不能访问外部类变量，因为静态内部类对象不依赖外部类对象，所以存在内部类对象不代表存在外部类对象
            System.out.println(FirstInnerClass.this.age);
            System.out.println(age);
        }
    }

    public static void main(String[] args) {
        InnerClassTest.FirstInnerClass innerClass = new InnerClassTest.FirstInnerClass();//注意和非静态内部类的new方式区别
        innerClass.test();
    }
}

public class InnerClassTest {
    public static void talk(Person person){
        person.speak();
    }
    public static void main(String[] args) {
        //只是创建一个匿名内部类的对象，并没有调用它，所以不会输出你好
        new Person() {
            @Override
            public void speak() {
                System.out.println("你好");
            }
        };

        InnerClassTest.talk(new Person() {
            @Override
            public void speak() {
                System.out.println("Hello");
            }
        });

        //通常的new一个线程
        new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println("萨瓦迪卡");
            }
        }).start();
    }
}

interface Person{
    public void speak();
}

public class Test2 {
    public void show() {
        //作用域仅限于该方法
        class Inner {
            public void fun() {
                System.out.println("helloworld");
            }
        }
        new Inner().fun();
    }
    public static void main(String[] args) {
        new Test2().show();
    }
}