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
有很多方法可以转换第一个大写单词的第一个字母。我有个主意。这很简单:
public String capitalize(String str){
/* The first thing we do is remove whitespace from string */
String c = str.replaceAll("\\s+", " ");
String s = c.trim();
String l = "";
for(int i = 0; i < s.length(); i++){
if(i == 0){ /* Uppercase the first letter in strings */
l += s.toUpperCase().charAt(i);
i++; /* To i = i + 1 because we don't need to add
value i = 0 into string l */
}
l += s.charAt(i);
if(s.charAt(i) == 32){ /* If we meet whitespace (32 in ASCII Code is whitespace) */
l += s.toUpperCase().charAt(i+1); /* Uppercase the letter after whitespace */
i++; /* Yo i = i + 1 because we don't need to add
value whitespace into string l */
}
}
return l;
}
其他回答
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);
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()
}
我在Java 8中编写了一个更具可读性的解决方案。
public String firstLetterCapitalWithSingleSpace(final String words) {
return Stream.of(words.trim().split("\\s"))
.filter(word -> word.length() > 0)
.map(word -> word.substring(0, 1).toUpperCase() + word.substring(1))
.collect(Collectors.joining(" "));
}
这个解决方案的要点可以在这里找到:https://gist.github.com/Hylke1982/166a792313c5e2df9d31
有很多方法可以转换第一个大写单词的第一个字母。我有个主意。这很简单:
public String capitalize(String str){
/* The first thing we do is remove whitespace from string */
String c = str.replaceAll("\\s+", " ");
String s = c.trim();
String l = "";
for(int i = 0; i < s.length(); i++){
if(i == 0){ /* Uppercase the first letter in strings */
l += s.toUpperCase().charAt(i);
i++; /* To i = i + 1 because we don't need to add
value i = 0 into string l */
}
l += s.charAt(i);
if(s.charAt(i) == 32){ /* If we meet whitespace (32 in ASCII Code is whitespace) */
l += s.toUpperCase().charAt(i+1); /* Uppercase the letter after whitespace */
i++; /* Yo i = i + 1 because we don't need to add
value whitespace into string l */
}
}
return l;
}
String toUpperCaseFirstLetterOnly(String str) {
String[] words = str.split(" ");
StringBuilder ret = new StringBuilder();
for(int i = 0; i < words.length; i++) {
ret.append(Character.toUpperCase(words[i].charAt(0)));
ret.append(words[i].substring(1));
if(i < words.length - 1) {
ret.append(' ');
}
}
return ret.toString();
}
