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
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。
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());
}
}
这里我们要实现单词的首字符大写
public static void main(String[] args) {
String input ="my name is ranjan";
String[] inputArr = input.split(" ");
for(String word : inputArr) {
System.out.println(word.substring(0, 1).toUpperCase()+word.substring(1,word.length()));
}
}
}
//输出:My Name Is Ranjan
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。
public static void main(String[] args) throws IOException {
String words = "this is a test";
System.out.println(Arrays.asList(words.split(" ")).stream().reduce("",(a, b)->(a + " " + b.substring(0, 1).toUpperCase() + b.substring(1))));
}
}
String toBeCapped = "i want this sentence capitalized";
String[] tokens = toBeCapped.split("\\s");
toBeCapped = "";
for(int i = 0; i < tokens.length; i++){
char capLetter = Character.toUpperCase(tokens[i].charAt(0));
toBeCapped += " " + capLetter + tokens[i].substring(1);
}
toBeCapped = toBeCapped.trim();
