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

您也可以非常简单地这样做,并保留任何双空格、前导空格和尾随空格

public static String capitalizeWords(String text) {

    StringBuilder sb = new StringBuilder();
    if(text.length()>0){
        sb.append(Character.toUpperCase(text.charAt(0)));
    }
    for (int i=1; i<text.length(); i++){
        String chPrev = String.valueOf(text.charAt(i-1));
        String ch = String.valueOf(text.charAt(i));

        if(Objects.equals(chPrev, " ")){
            sb.append(ch.toUpperCase());
        }else {
            sb.append(ch);
        }

    }

    return sb.toString();

}

其他回答

如果你只担心第一个单词的首字母大写:

private String capitalize(final String line) {
   return Character.toUpperCase(line.charAt(0)) + line.substring(1);
}

我需要做一个通用的toString(Object obj)帮助类函数,在那里我必须将字段名转换为方法名-传递对象的getXXX()。

下面是代码

/**
 * @author DPARASOU
 * Utility method to replace the first char of a string with uppercase but leave other chars as it is.
 * ToString() 
 * @param inStr - String
 * @return String
 */
public static String firstCaps(String inStr)
{
    if (inStr != null && inStr.length() > 0)
    {
        char[] outStr = inStr.toCharArray();
        outStr[0] = Character.toUpperCase(outStr[0]);
        return String.valueOf(outStr);
    }
    else
        return inStr;
}

我的toString()实用程序是这样的

public static String getToString(Object obj)
{
    StringBuilder toString = new StringBuilder();
    toString.append(obj.getClass().getSimpleName());
    toString.append("[");
    for(Field f : obj.getClass().getDeclaredFields())
    {
        toString.append(f.getName());
        toString.append("=");
        try{
            //toString.append(f.get(obj)); //access privilege issue
            toString.append(invokeGetter(obj, firstCaps(f.getName()), "get"));
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
        toString.append(", ");        
    }
    toString.setCharAt(toString.length()-2, ']');
    return toString.toString();
}

这是我做的另一种方法

    StringBuilder str=new StringBuilder("pirai sudie test test");

    str.setCharAt(0,Character.toUpperCase(str.charAt(0)));

    for(int i=str.length()-1;i>=0;i--)
    {
        if(Character.isSpaceChar(str.charAt(i)))
            str.setCharAt(i+1,Character.toUpperCase(str.charAt(i+1)));
    }

    System.out.println(str);
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);

最基本和最简单的理解方法(我认为):

import java.util.Scanner;

public class ToUpperCase {
    static Scanner kb = new Scanner(System.in);

    public static String capitalize(String str){
        /* Changes 1st letter of every word 
           in a string to upper case
         */
        String[] ss = str.split(" ");
        StringBuilder[] sb = new StringBuilder[ss.length];
        StringBuilder capped = new StringBuilder("");
        str = "";

        // Capitalise letters
        for (int i = 0; i < ss.length; i++){
            sb[i] = new StringBuilder(ss[i]); // Construct and assign
            str += Character.toUpperCase(ss[i].charAt(0)); // Only caps
            //======================================================//

            // Replace 1st letters with cap letters
            sb[i].setCharAt(0, str.charAt(i)); 
            capped.append(sb[i].toString() + " ");  // Formatting
        }
        return capped.toString();
    }

    public static void main(String[] args){
        System.out.println(capitalize(kb.nextLine()));
    }
}