Fruit 扩展了 HealthyFood，HealthyFood 扩展了 Food，但 Fruit 和 HealthyFood 都不能访问私有字符串名称；或私人 int cal；

Question

说明：

对于本练习，您将创建一个带有健康食品子class 的食品超级class。 HealthyFood 还将有一个 Fruit 子class。创建这些 classes 后，在 FoodTester class.

中测试结果

食物 class 将有两个实例变量，一个用于存储名称，一个用于存储卡路里。

食物也应该有两个访问器（getter 方法）：

public String getName()
public int getCal()

HealthyFood class 将只有一个实例变量 group，它表示食物组并且应该具有以下访问器（getter 方法）：

public String getGroup()

Fruit class 将有两个实例变量，一个布尔值指示符（如果水果是本地的）和颜色。访问器方法应该是：

public boolean isLocal()
public String getColor()

构造函数应遵循以下格式：

public Food (String foodName, int calories)
public HealthyFood(String foodName, int calories, String foodGroup)
public Fruit(String foodName, int calories, boolean isLocal, String foodColor)

最后，Food class 应该有一个 toString 打印：名字有卡路里

例如：

Ice Cream has 200 calories

实际代码：

FoodTester.Java

public class FoodTester {
    public static void main(String[] args) {
        
    }
}

Fruit.java

public class Fruit extends HealthyFood {
    private boolean local;
    private String color;
    
    public Fruit(String foodName, int calories, boolean isLocal, String foodColor){
        super(name, calories, "Strings");
        local = isLocal;
        color = foodColor;
    }
    
    public boolean isLocal(){
        return local;
    }
    
    public String getColor(){
        return color;
    }
}

HealthyFood.java

public class HealthyFood extends Food {
    private String group;
    
    public HealthyFood(String foodName, int calories, String foodGroup){
        super(name, cal);
        group = foodGroup;
    }
    
    public String getGroup(){
        return group;
    }
}

Food.java

public class Food {
    private String name;
    private int cal;
    
    public Food(String foodName, int calories){
        name = foodName;
        cal = calories;
    }
    
    public String getName(){
        return name;
    }
    
    public int getCal(){
        return cal;
    }
    
    public String toString(){
        return name + " has " + cal + " calories";
    }
}

错误信息：

HealthyFood.java:6: error: name has private access in Food
        super(name, cal);
              ^
HealthyFood.java:6: error: cal has private access in Food
        super(name, cal);
                    ^
Fruit.java:7: error: name has private access in Food
        super(name, calories, "Strings");
              ^
3 errors

Answer 1

尝试这样修改：

public HealthyFood(String foodName, int calories, String foodGroup){
    super(foodName, calories);

和

public Fruit(String foodName, int calories, boolean isLocal, String foodColor){
       super(foodName, calories, "Strings");

您应该将 foodName 或 calories 作为超级构造函数的参数。

Fruit 扩展了 HealthyFood，HealthyFood 扩展了 Food，但 Fruit 和 HealthyFood 都不能访问私有字符串名称；或私人 int cal；

Fruit extends HealthyFood which extends Food, yet neither Fruit nor HealthyFood can access private String name; or private int cal;

java

subclass

superclass