如何 clone/copy 我自己的实例 class？

Question

这种clone的使用方式是否正确？我每次都会收到运行时错误。还有人可以建议在这个class中编写复制构造函数的方法吗？

public class Pair {
    final StringBuffer x;
    final StringBuffer y;

    public Pair(StringBuffer x, StringBuffer y) {
        this.x = x;
        this.y = y;
    }

    public StringBuffer getX() {
        return x;
    }

    public StringBuffer getY() {
        return y;
    }

    public Pair clone() {
        Pair p = new Pair(new StringBuffer(), new StringBuffer());
        try {
            p = (Pair) super.clone();
        } catch (CloneNotSupportedException e) {
            throw new Error();
        }
        return p;
    }
}

Answer 1

复制构造函数：

public Pair(Pair other) {
  this.x = new StringBuffer(other.x.toString());
  this.y = new StringBuffer(other.y.toString());
}

你应该avoid using clone():

clone is very tricky to implement correctly in all circumstances, nearly to the point of being pathological

the importance of copying objects will always remain, since object fields often need to be defensively copied

copy constructors and static factory methods provide an alternative to clone, and are much easier to implement

如何 clone/copy 我自己的实例 class？

How to clone/copy an instance of my own class?

java

deep-copy