加入List< String>在Java中用逗号和"and"表示 [英] Joining a List<String> in Java with commas and "and"

问题描述

提供列表

List<String> l = new ArrayList<String>();
l.add("one");
l.add("two");
l.add("three");

我有方法

String join(List<String> messages) {
        if (messages.isEmpty()) return "";
        if (messages.size() == 1) return messages.get(0);
        String message = "";
        message = StringUtils.join(messages.subList(0, messages.size() -2), ", ");
        message = message + (messages.size() > 2 ? ", " : "") + StringUtils.join(messages.subList(messages.size() -2, messages.size()), ", and ");
        return message;
    }

，对于l，它产生"1、2和3". 我的问题是，是否有一个标准的方法(apache-commons)能做到相同?例如

which, for l, produces "one, two, and three". My question is, is there a standard (apache-commons) method that does the same?, eg

WhatEverUtils.join(l, ", ", ", and ");

要澄清.我的问题是没有使这种方法起作用.它按照我想要的方式工作，经过了测试，一切都很好.我的问题是我找不到实现此类功能的类似apache-commons的模块.这让我感到惊讶，因为我不能成为第一个需要此功能的人.

To clarify. My problem is not getting this method to work. It works just as I want it to, it's tested and all is well. My problem is that I could not find some apache-commons-like module which implements such functionality. Which surprises me, since I cannot be the first one to need this.

但是也许其他所有人都做过

But then maybe everyone else has just done

StringUtils.join(l, ", ").replaceAll(lastCommaRegex, ", and");

推荐答案

在Java 8中，您可以使用String.join()，如下所示:

In Java 8 you can use String.join() like following:

Collection<String> elements = ....;
String result = String.join(", ", elements);

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