初始化一个对象的多个构造函数

Question

我想知道是否可以调用多个构造函数并通过它们初始化一个对象值。我一直在寻找答案，但我没有找到答案;让我告诉你一些代码，并提前感谢你的帮助：

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

你不能调用多个构造函数来创建一个类的实例。每次调用都会创建一个与另一个完全不同的新实例。同时设置int领域和使用构造数组，其值应传递给构造本身：

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); 
} 

这相当于

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); 
}