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
来自Java 9+
你可以像这样使用String::replaceAll:
public static void upperCaseAllFirstCharacter(String text) {
String regex = "\\b(.)(.*?)\\b";
String result = Pattern.compile(regex).matcher(text).replaceAll(
matche -> matche.group(1).toUpperCase() + matche.group(2)
);
System.out.println(result);
}
例子:
upperCaseAllFirstCharacter("hello this is Just a test");
输出
Hello This Is Just A Test
其他回答
s.toLowerCase().trim();
result += Character.toUpperCase(s.charAt(0));
result += s.substring(1, s.indexOf(" ") + 1);
s = s.substring(s.indexOf(" ") + 1);
do {
if (s.contains(" ")) {
result += " ";
result += Character.toUpperCase(s.charAt(0));
result += s.substring(1, s.indexOf(" "));
s = s.substring(s.indexOf(" ") + 1);
} else {
result += " ";
result += Character.toUpperCase(s.charAt(0));
result += s.substring(1);
break;
}
} while (true);
System.out.println(result);
这是我的解决方案。
今晚我偶然发现了这个问题，并决定研究一下。我发现Neelam Singh的答案几乎在那里，所以我决定解决这个问题(断在空字符串上)，导致系统崩溃。
您正在寻找的方法名为capString(String s)。 它把“这里才早上5点”变成了“这里才早上5点”。
代码注释得很好，喜欢吧。
package com.lincolnwdaniel.interactivestory.model;
public class StringS {
/**
* @param s is a string of any length, ideally only one word
* @return a capitalized string.
* only the first letter of the string is made to uppercase
*/
public static String capSingleWord(String s) {
if(s.isEmpty() || s.length()<2) {
return Character.toUpperCase(s.charAt(0))+"";
}
else {
return Character.toUpperCase(s.charAt(0)) + s.substring(1);
}
}
/**
*
* @param s is a string of any length
* @return a title cased string.
* All first letter of each word is made to uppercase
*/
public static String capString(String s) {
// Check if the string is empty, if it is, return it immediately
if(s.isEmpty()){
return s;
}
// Split string on space and create array of words
String[] arr = s.split(" ");
// Create a string buffer to hold the new capitalized string
StringBuffer sb = new StringBuffer();
// Check if the array is empty (would be caused by the passage of s as an empty string [i.g "" or " "],
// If it is, return the original string immediately
if( arr.length < 1 ){
return s;
}
for (int i = 0; i < arr.length; i++) {
sb.append(Character.toUpperCase(arr[i].charAt(0)))
.append(arr[i].substring(1)).append(" ");
}
return sb.toString().trim();
}
}
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);
String s="hi dude i want apple";
s = s.replaceAll("\\s+"," ");
String[] split = s.split(" ");
s="";
for (int i = 0; i < split.length; i++) {
split[i]=Character.toUpperCase(split[i].charAt(0))+split[i].substring(1);
s+=split[i]+" ";
System.out.println(split[i]);
}
System.out.println(s);
来自Java 9+
你可以像这样使用String::replaceAll:
public static void upperCaseAllFirstCharacter(String text) {
String regex = "\\b(.)(.*?)\\b";
String result = Pattern.compile(regex).matcher(text).replaceAll(
matche -> matche.group(1).toUpperCase() + matche.group(2)
);
System.out.println(result);
}
例子:
upperCaseAllFirstCharacter("hello this is Just a test");
输出
Hello This Is Just A Test
