Java有一个默认的复制构造函数（像C ++）？ [英] Does Java have a default copy constructor (like in C++)?

问题描述

Java是否具有C ++的默认复制构造函数？如果它有一个 - 如果我明确声明另一个构造函数（而不是复制构造函数），它仍然可用？

Does Java has a default copy constructor as C++? If it has one - does it remain usable if I declare another constructor (not a copy constructor) explicitly?

推荐答案

Java不有bulit-in复制构造函数。

Java does not have bulit-in copy constructors.

但你可以编写自己的这样的构造函数。参见下面的示例：

But you can write your own such constructors. See an example below:

class C{
    private String field;
    private int anotherField;
    private D d;

    public C(){}

    public C(C other){
        this.field = other.field;
        this.anotherField = other.anotherField;
        this.d = new D(other.d); //watch out when copying mutable objects; they should provide copy constructors, as well. Otherwise, a deep copy may not be possible
    }

    //getters and setters
}

class D{//mutable class

    //fields
    public D(D other){
        //this is a copy constructor, like the one for C class
    }
}

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