問題描述

我需要一個來自 String 對象的 Iterator<Character>.Java 中是否有任何可用函數可以為我提供此功能，還是我必須自己編寫代碼?

I need a Iterator<Character> from a String object. Is there any available function in Java that provides me this or do I have to code my own?

推薦答案

一種選擇是使用 番石榴:

ImmutableList<Character> chars = Lists.charactersOf(someString);
UnmodifiableListIterator<Character> iter = chars.listIterator();

這會生成一個由給定字符串支持的不可變字符列表(不涉及復制).

This produces an immutable list of characters that is backed by the given string (no copying involved).

如果您最終自己這樣做，我建議不要像許多其他示例那樣公開 Iterator 的實現類.我建議改為創建自己的實用程序類并公開靜態工廠方法:

If you end up doing this yourself, though, I would recommend not exposing the implementation class for the Iterator as a number of other examples do. I'd recommend instead making your own utility class and exposing a static factory method:

public static Iterator<Character> stringIterator(final String string) {
  // Ensure the error is found as soon as possible.
  if (string == null)
    throw new NullPointerException();

  return new Iterator<Character>() {
    private int index = 0;

    public boolean hasNext() {
      return index < string.length();
    }

    public Character next() {
      /*
       * Throw NoSuchElementException as defined by the Iterator contract,
       * not IndexOutOfBoundsException.
       */
      if (!hasNext())
        throw new NoSuchElementException();
      return string.charAt(index++);
    }

    public void remove() {
      throw new UnsupportedOperationException();
    }
  };
}

這篇關于Java:如何獲取迭代器<字符>從字符串的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！