Inner class is not public 实例化新的 inner class 时出错

Question

我有这个class

package com.rafael;

public class Vehicle {

    public class InnerVehicle {
        InnerVehicle() {
            System.out.println("This is InnerVehicle");
        }
    }
}

并且在主函数中

import com.rafael.Vehicle;

public class VehicleTest {
    public static void main(String[] args) {
        Vehicle v = new Vehicle();
        Vehicle.InnerVehicle iv = v.new InnerVehicle();
    }
}

但这总是给我错误：

java: InnerVehicle() is not public in com.rafael.Vehicle.InnerVehicle; cannot be accessed from outside package

Answer 1

制作内classpublic static

否则，您需要外部对象 class 来创建内部实例，正如 Tim Biegeleisen 已经提到的那样

并使您的内部 class public 的构造函数也成为

类似于：

public class Vehicle {    
    public static class InnerVehicle {
        public InnerVehicle() {
            System.out.println("This is InnerVehicle");
        }
    }
}

Answer 2

您指的是嵌套 class 不正确。您只能在包含 class:

的上下文中实例化内部 class

Vehicle v = new Vehicle();
InnerVehicle iv = v.new InnerVehicle();

您使用的语法用于静态嵌套 class，在这种情况下，您的代码将如下所示：

public class Vehicle {
    static public class InnerVehicle {
        InnerVehicle() {
            System.out.println("This is InnerVehicle");
        }
    }
}

Vehicle.InnerVehicle iv = new Vehicle.InnerVehicle();

Inner class is not public 实例化新的 inner class 时出错

Inner class is not public error when instantiating new inner class

java

access-modifiers

inner-classes