java - 类 - Java 中的内部类和属性

Question

我一直在尝试制作一个瓶子类，其中包括啤酒的内部类。为什么外部类“bottle”中的属性 beer 无效？这样“私有(private)‘啤酒’字段永远不会分配？

这是我的代码

public class Bottle {
    private Beer beer; //THE PROBLEM IS IN THIS LINE//
    private double volume;


    public Bottle () {
    }

    public Beer getBeer {return beer;}
    public void Beer setBeer(Beer beer){return beer;}

    public double getVolume {return volume};
    public void setVolume (double volume) {return this.volume = volume;}


    public class Beer {
        private String brandName;
        private double strength;

        public Beer (String brandName, double strength) {
            this.brandName = brandName;
            this.strength = strength;
        }

        public String getbrandName() {return brandName;}
        public void setbrandName(String brandName) {return this.brandName = brandName;}
        public double getstrength() {return strength;}
        public void setstrength(double strength) {return this.strength = strength;}
    }
}

Answer 1

您的代码没有一个问题，而是有很多问题。主要是语法错误。我更正了它以使其编译:

public class Bottle {

    private Beer beer = new Beer("Beck's", 5.1);
    private double volume;

    public Bottle () {
    }

    public Beer getBeer() { return beer; }
    public Beer setBeer(Beer beer) {return beer;}

    public double getVolume() { return volume; }
    public void setVolume(double volume) { this.volume = volume; }

    public class Beer {
        private String brandName;
        private double strength;

        public Beer (String brandName, double strength) {
            this.brandName = brandName;
            this.strength = strength;
        }

        public String getbrandName() {return brandName;}
        public void setbrandName(String brandName) { this.brandName = brandName;}
        public double getstrength() {return strength;}
        public void setstrength(double strength) { this.strength = strength;}
    }
}