java - Collections.sort 与 Arrays.sort - Java 中

Question

我首先进行了这种排序:

List<String> items = new ArrayList<String>();

Comparator<items> ignoreLeadingThe = new Comparator<items>() {
    public int compare(String a, String b) {
        a = a.replaceAll("(?i(^the\\s+", "");
        b = b.replaceAll("(?i(^the\\s+", "");
        return a.compareToIgnoreCase(b);
    }
};

Collections.sort(items, ignoreLeadingThe);

现在我正在这样做:

ItemObject[] io = new ItemObject[items.size()];

Comparator<ItemObject> ignoreLeadingThe = new Comparator<ItemObject>() {
    public int compare(ItemObject a, ItemObject b) {
        a.name = a.name.replaceAll("(?i(^the\\s+", "");
        b.name = b.name.replaceAll("(?i(^the\\s+", "");
        return a.name.compareToIgnoreCase(b.name);
    }
};

Arrays.sort(io, ignoreLeadingThe);

当我将 ArrayList 排序到顶部时，它表现正常；它忽略了“The”并相应地对列表进行了排序；但它实际上并没有影响列表的输出。

但是，当我对常规Array(填充对象而不是字符串)进行排序时，底部代码实际上删除了“The”。例如，“ clown ”将变成“ clown ”。

有人看出这里出了什么问题吗？

Answer 1

正如我在 my comment 中所述,

You're overwriting a.name and b.name. Declare separate local variables for the transformed names and use those in your compareToIgnoreCase.

...或者只使用一个大的表达式。所以，尝试这样的事情......

final Comparator<ItemObject> ignoreLeadingThe = new Comparator<ItemObject>() {

  final Pattern pattern = Pattern.compile("(?i(^the\\s+");

  public int compare(final ItemObject a, final ItemObject b) {
    return pattern.matcher(a.name).replaceAll("")
        .compareToIgnoreCase(pattern.matcher(b.name).replaceAll(""));
  }
};