内部类&Lambda

1.公开的内部类实例化

public class Outter {
    public class Inner{
        public void method(){
            System.out.println("内部方法成功被调用了!");
        }
    }
}
public class Main {
    public static void main(String[] args) {
        Outter.Inner i = new Outter().new Inner();
        i.method();
    }
}

2.私有的内部类

public class Outter {
    private class Inner{
        public void method(){
            System.out.println("内部方法成功被调用了!");
        }
    }

    public void test(){
        Inner inner = new Inner(); // 创建内部类的实例
        inner.method(); // 调用内部类的方法
    }
}
public class Main {
    public static void main(String[] args) {
        Outter outter = new Outter();
        outter.test();
    }
}

3.静态公开内部类的实例化

public class Outter {
    public static class Inner{
        public void method(){
            System.out.println("内部方法成功被调用了!");
        }
    }

    public void test(){
        Inner inner = new Inner(); // 创建内部类的实例
        inner.method(); // 调用内部类的方法
    }
}
public class Main {
    public static void main(String[] args) {
        Outter.Inner i = new Outter.Inner();
        i.method();
    }
}

4.静态内部类中的静态方法(共有)

5.局部内部类

public class Outer {
    public void test() {
        class LocalInner {
            private void method() {
                System.out.println("局部内部类的方法被调用了!");
            }
        }

        LocalInner localInner = new LocalInner(); // 创建局部内部类的实例
        localInner.method(); // 调用局部内部类的方法
    }

    public static void main(String[] args) {
        Outer outer = new Outer();
        outer.test(); // 调用外部类的方法
    }
}

4.匿名内部类

//调用方法
public interface Swim {
    void swim();
}
        new Swim(){

            @Override
            public void swim() {
                System.out.println("铁汁, 我们去游泳吧!");
            }
        }.swim();

//实际开发使用匿名内部类的场景
        JButton jButton = new JButton();
        jButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                //具体的代码逻辑
            }
        });

5.Lambda

public class Test6 {
    public static void main(String[] args) {
        useInter((double a,double b)->{return a+b;});

        useInter(new Inter() {
            @Override
            public double method(double a, double b) {
                return a + b;
            }
        });
    }

    public static void useInter(Inter inter){
        double result = inter.method(9.9,0.1);
        System.out.println(result);
    }
}
interface Inter{
    double method(double a, double b);
}