Java中是否内置了一个函数,使字符串中每个单词的第一个字符大写,而不影响其他字符?

例子:

乔恩·斯基特->乔恩·斯基特 miles o'Brien -> miles o'Brien (B仍然是大写,这排除了Title Case) 老麦当劳->

*(老麦当劳也会被发现,但我不指望它有那么聪明。)

快速浏览一下Java字符串文档就会发现只有toUpperCase()和toLowerCase(),它们当然没有提供所需的行为。当然,谷歌的结果主要是这两个函数。它看起来像一个已经被发明出来的轮子,所以问一下也无妨,这样我以后就可以用它了。


当前回答

Use:

    String text = "jon skeet, miles o'brien, old mcdonald";

    Pattern pattern = Pattern.compile("\\b([a-z])([\\w]*)");
    Matcher matcher = pattern.matcher(text);
    StringBuffer buffer = new StringBuffer();
    while (matcher.find()) {
        matcher.appendReplacement(buffer, matcher.group(1).toUpperCase() + matcher.group(2));
    }
    String capitalized = matcher.appendTail(buffer).toString();
    System.out.println(capitalized);

其他回答

Simple answer by program:


public class StringCamelCase {
    public static void main(String[] args) {
        String[] articles = {"the ", "a ", "one ", "some ", "any "};
        String[] result = new String[articles.length];
        int i = 0;
        for (String string : articles) {
            result[i++] = toUpercaseForstChar(string);
        }

        for (String string : result) {
            System.out.println(string);
        }
    }
    public static String toUpercaseForstChar(String string){
        return new String(new char[]{string.charAt(0)}).toUpperCase() + string.substring(1,string.length());
    }
}

worddutil .capitalize(str) (from apache common -text)

(注意:如果你需要“fOO BAr”变成“fOO BAr”,那么用大写的(..)代替)

下面是这个问题的Kotlin版本:

fun capitalizeFirstLetterOfEveryWord(text: String): String
{
    if (text.isEmpty() || text.isBlank())
    {
        return ""
    }

    if (text.length == 1)
    {
        return Character.toUpperCase(text[0]).toString()
    }

    val textArray = text.split(" ")
    val stringBuilder = StringBuilder()

    for ((index, item) in textArray.withIndex())
    {
        // If item is empty string, continue to next item
        if (item.isEmpty())
        {
            continue
        }

        stringBuilder
            .append(Character.toUpperCase(item[0]))

        // If the item has only one character then continue to next item because we have already capitalized it.
        if (item.length == 1)
        {
            continue
        }

        for (i in 1 until item.length)
        {
            stringBuilder
                .append(Character.toLowerCase(item[i]))
        }

        if (index < textArray.lastIndex)
        {
            stringBuilder
                .append(" ")
        }
    }

    return stringBuilder.toString()
}

1. Java 8流

public static String capitalizeAll(String str) {
    if (str == null || str.isEmpty()) {
        return str;
    }

    return Arrays.stream(str.split("\\s+"))
            .map(t -> t.substring(0, 1).toUpperCase() + t.substring(1))
            .collect(Collectors.joining(" "));
}

例子:

System.out.println(capitalizeAll("jon skeet")); // Jon Skeet
System.out.println(capitalizeAll("miles o'Brien")); // Miles O'Brien
System.out.println(capitalizeAll("old mcdonald")); // Old Mcdonald
System.out.println(capitalizeAll(null)); // null

对于foo bAR到foo bAR,替换map()方法如下:

.map(t -> t.substring(0, 1).toUpperCase() + t.substring(1).toLowerCase())

2. 字符串()(Java 9+)

ublic static String capitalizeAll(String str) {
    if (str == null || str.isEmpty()) {
        return str;
    }

    return Pattern.compile("\\b(.)(.*?)\\b")
            .matcher(str)
            .replaceAll(match -> match.group(1).toUpperCase() + match.group(2));
}

例子:

System.out.println(capitalizeAll("12 ways to learn java")); // 12 Ways To Learn Java
System.out.println(capitalizeAll("i am atta")); // I Am Atta
System.out.println(capitalizeAll(null)); // null

3.Apache Commons文本

System.out.println(WordUtils.capitalize("love is everywhere")); // Love Is Everywhere
System.out.println(WordUtils.capitalize("sky, sky, blue sky!")); // Sky, Sky, Blue Sky!
System.out.println(WordUtils.capitalize(null)); // null

titlecase:

System.out.println(WordUtils.capitalizeFully("fOO bAR")); // Foo Bar
System.out.println(WordUtils.capitalizeFully("sKy is BLUE!")); // Sky Is Blue!

有关详细信息,请查看本教程。

试试这个:

 private String capitalizer(String word){

        String[] words = word.split(" ");
        StringBuilder sb = new StringBuilder();
        if (words[0].length() > 0) {
            sb.append(Character.toUpperCase(words[0].charAt(0)) + words[0].subSequence(1, words[0].length()).toString().toLowerCase());
            for (int i = 1; i < words.length; i++) {
                sb.append(" ");
                sb.append(Character.toUpperCase(words[i].charAt(0)) + words[i].subSequence(1, words[i].length()).toString().toLowerCase());
            }
        }
        return  sb.toString();
    }