传递的ArrayList的价值，而不是只引用 [英] Passing ArrayList as value only and not reference

问题描述

简单地说，我有一个ArrayList参数的方法。在该方法中我修改的ArrayList内容相关仅什么是该方法返回的目的。因此，我不希望在所有（即不作为引用传递）。

Simply put, I have a method with an ArrayList parameter. In the method I modify the contents of the ArrayList for purposes relevant only to what is returned by the method. Therefore, I do not want the ArrayList which is being passed as the parameter to be affected at all (i.e. not passed as a reference).

我已经试过一切都未能达到预期的效果。什么我需要做的，这样我只能在方法中使用ArrayList的副本，但又不希望它改变实际变量？

Everything I have tried has failed to achieve the desired effect. What do I need to do so that I can make use of a copy of the ArrayList within the method only, but not have it change the actual variable?

推荐答案

即使你有办法传递数组列表作为一个拷贝，而不是引用它本来只是一个浅拷贝。

Even if you had a way to pass the array list as a copy and not by reference it would have been only a shallow copy.

我会做这样的事情：

void foo(final ArrayList list) {

    ArrayList listCopy = new ArrayList(list);
    // Rest of the code

}

和刚才复制的名单上的工作。

And just work on the copied list.

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