java - 使用 'this' 关键字调用基本构造函数并使用方法调用来设置私有(private)成员

Question

几个问题:

1) 如果您有一个父类(super class) Monster 并且您创建了一个继承其行为的子类。在子类的每个构造函数中调用super是一种很好的做法。下面我所做的是在第一个重载构造函数中调用它一次，并在第二个重载构造函数中使用 this(..) 调用第一个构造函数，这是最佳实践吗？

2) 是否最好使用方法调用，即 setHealthAid(10) 来设置 use 赋值的类字段，即

mHealthAid = -1;
mHasInvisibleMode = false;

没有实现 getter 和 setter 的类片段以使其简短。

public class Monster {  
    private int mStrength;  
    private int mScareFactor;   

    public Monster(int strength, int scareFactor) {     
        setStrength(strength);      
        setScareFactor(scareFactor);    
    }   

    /* Getters and setters */
}

public class BigBoss extends Monster {  
    private int mHealthAid; 
    private boolean mHasInvisibleMode;  

    public BigBoss(int strength, int scareFactor) {     
        super(strength, scareFactor);       
        setHealthAid(-1);       
        setHasInvisibleMode(false);     
    }       
    public BigBoss(int strength, 
                   int scareFactor, 
                   int healthAid, 
                   boolean hasInvisibleMode) {      
       this(strength, scareFactor);     
       setHealthAid(healthAid);     
       setHasInvisibleMode(hasInvisibleMode);   
    }   

    /* Getters and setters */
}

非常感谢您的建议，

Answer 1

1) If you have a super class Monster and you create a subclass that inherits its behaviour. Its it good practice to call super in every constructor in the subclass. What I have done below is call it once in the first overloaded constructor and in the second overloaded constructor I call the first using this(..) Is this the best practice?

您应该有一个构造函数，它采用正确实例化类所需的所有参数。在参数较少的第二个构造函数中，您应该使用 this 来调用第一个构造函数，并为缺少的参数传递默认值。喜欢:

public BigBoss(int strength, int scareFactor) {     
    this(strength, scareFactor, -1, false);
}       

//costructor with all required params to instantiate BigBoss properly  
public BigBoss(int strength, 
               int scareFactor, 
               int healthAid, 
               boolean hasInvisibleMode) {
   super(strength, scareFactor);     
   mHealthAid = healthAid;     
   mHasInvisibleMode = hasInvisibleMode;   
} 

2) Is it better to use the method calls i.e setHealthAid(10) to set the class fields of use assignment instead

您可以使用同一类中的字段 setter 来设置属性。但由于你们已经在同一个类中，所以您应该直接使用属性来设置值，即。

mHealthAid = -1;
mHasInvisibleMode = false;

这使得代码变得有点简洁，并且由于不涉及方法调用，因此您获得的性能提升很小。