初始化一個對象的多個構造函數

Question

我想知道是否可以調用多個構造函數並通過它們初始化一個對象值。我一直在尋找答案，但我沒有找到答案;讓我告訴你一些代碼，並提前感謝你的幫助：

int MAX_VALUE; // Field variable 
    boolean[] elements = new boolean[10000]; // Field variable 

    public IntegerSet(int maxValue) { 
     this.MAX_VALUE = maxValue; 
    } 
    public IntegerSet(boolean[] tmp) { 
     int i = 0; 

     for(i = 0; i < tmp.length; ++i) 
      this.elements[i] = tmp[i]; 

     this.elements = Arrays.copyOf(this.elements, tmp.length); 
    } 

/*In main:*/ 

    // I just want to have one object, s1, and I want to be able 
    // to access MAX_VALUE and elements by s1.MAX_VALUE and s1.elements 
    IntegerSet s1 = new IntegerSet(50); 
    /* SOMETHING that uses second constructor with object s1*/ 

Answer 1

你不能調用多個構造函數來創建一個類的實例。每次調用都會創建一個與另一個完全不同的新實例。同時設置int領域和使用構造數組，其值應傳遞給構造本身：

public IntegerSet(boolean[] tmp, int maxValue) { 
    this.MAX_VALUE = maxValue; 
    int i = 0; 

    for(i = 0; i < tmp.length; ++i) 
     this.elements[i] = tmp[i]; 

    this.elements = Arrays.copyOf(this.elements, tmp.length); 
} 

這相當於

public IntegerSet(boolean[] tmp, int maxValue) { 
    this(maxValue); // will call the constructor that takes one parameter 
    int i = 0; 

    for(i = 0; i < tmp.length; ++i) 
     this.elements[i] = tmp[i]; 

    this.elements = Arrays.copyOf(this.elements, tmp.length); 
}