Java：迭代迭代对象的属性 [英] Java: Changing the properties of an iterable object while iterating over it

问题描述

以下代码只是为了产生一个问题的示例：

The following code is just to produce an example of the problem:

 public static void main(String[] args) {
  Collection<Integer> src = new ArrayList<Integer>();
  Collection<Integer> dest = new ArrayList<Integer>();

  src.add(2);
  src.add(7);
  src.add(3);
  src.add(2201);
  src.add(-21);

  dest.add(10);

  while (src.size() != 0) {
   for (int i : dest) {
    int min = Collections.min(src);
    dest.add(min);
    src.remove(min);
   }
  }

 }

我是什么我想做的是按照特定顺序将所有内容从src移动到dest。 （这里，它是最小值，但这只是我真正问题的简化。）但是，我在迭代它时修改dest，并得到以下错误：

What I want to do is move everything from src to dest in a specific order. (Here, it's what is the minimum value, but that's just a simplification from my real problem.) However, I am modifying dest while iterating over it, and get the following error:

Exception in thread "main" java.util.ConcurrentModificationException
 at java.util.AbstractList$Itr.checkForComodification(Unknown Source)
 at java.util.AbstractList$Itr.next(Unknown Source)
 at nth23.experimental.MoveBetweenSets.main(MoveBetweenSets.java:25)

我该如何解决这个问题？

How can I get around this?

推荐答案

这是一种解决方法：

while (!src.isEmpty()) {
    int min = Collections.min(src);
    dest.add(min);
    src.remove(min);
}

但这可能会让事情变得更糟。更具体一点（如Jon所说）。

But this might be even make thing worse. Be a bit more specific (as Jon mentioned).

这篇关于Java：迭代迭代对象的属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！