package com.test;

 /**
   * @author Prasanth Pillai
   * @date 01-Feb-2012
   * @description : Below is the test class details
   * 
   * inputs a String from a user. Expect the String to contain spaces and    alphanumeric     characters only.
   * capitalizes all first letters of the words in the given String.
   * preserves all other characters (including spaces) in the String.
   * displays the result to the user.
   * 
   * Approach : I have followed a simple approach. However there are many string    utilities available 
   * for the same purpose. Example : WordUtils.capitalize(str) (from apache commons-lang)
   *
   */
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;

  public class Test {

public static void main(String[] args) throws IOException{
    System.out.println("Input String :\n");
    InputStreamReader converter = new InputStreamReader(System.in);
    BufferedReader in = new BufferedReader(converter);
    String inputString = in.readLine();
    int length = inputString.length();
    StringBuffer newStr = new StringBuffer(0);
    int i = 0;
    int k = 0;
    /* This is a simple approach
     * step 1: scan through the input string
     * step 2: capitalize the first letter of each word in string
     * The integer k, is used as a value to determine whether the 
     * letter is the first letter in each word in the string.
     */

    while( i < length){
        if (Character.isLetter(inputString.charAt(i))){
            if ( k == 0){
            newStr = newStr.append(Character.toUpperCase(inputString.charAt(i)));
            k = 2;
            }//this else loop is to avoid repeatation of the first letter in output string 
            else {
            newStr = newStr.append(inputString.charAt(i));
            }
        } // for the letters which are not first letter, simply append to the output string. 
        else {
            newStr = newStr.append(inputString.charAt(i));
            k=0;
        }
        i+=1;           
    }
    System.out.println("new String ->"+newStr);
    }
}

以下方法将所有字母转换为大写/小写，取决于它们靠近空格或其他特殊字符的位置。

public static String capitalizeString(String string) {
  char[] chars = string.toLowerCase().toCharArray();
  boolean found = false;
  for (int i = 0; i < chars.length; i++) {
    if (!found && Character.isLetter(chars[i])) {
      chars[i] = Character.toUpperCase(chars[i]);
      found = true;
    } else if (Character.isWhitespace(chars[i]) || chars[i]=='.' || chars[i]=='\'') { // You can add other chars here
      found = false;
    }
  }
  return String.valueOf(chars);
}

这是一个简单的函数

public static String capEachWord(String source){
    String result = "";
    String[] splitString = source.split(" ");
    for(String target : splitString){
        result += Character.toUpperCase(target.charAt(0))
                + target.substring(1) + " ";
    }
    return result.trim();
}

这里是一个lil程序，我是用来大写每个第一个字母单词在每个子文件夹的父目录。

private void capitalize(String string)
{
    List<String> delimiters = new ArrayList<>();
    delimiters.add(" ");
    delimiters.add("_");

    File folder = new File(string);
    String name = folder.getName();
    String[] characters = name.split("");

    String newName = "";
    boolean capitalizeNext = false;

    for (int i = 0; i < characters.length; i++)
    {
        String character = characters[i];

        if (capitalizeNext || i == 0)
        {
            newName += character.toUpperCase();
            capitalizeNext = false;
        }
        else
        {
            if (delimiters.contains(character)) capitalizeNext = true;
            newName += character;
        }
    }

    folder.renameTo(new File(folder.getParent() + File.separator + newName));
}

import java.io.*;
public class Upch2
{
   BufferedReader br= new BufferedReader( new InputStreamReader(System.in));
   public void main()throws IOException
    { 
        System.out.println("Pl. Enter A Line");
        String s=br.readLine();
        String s1=" ";
        s=" "+s;
        int len=s.length();
        s= s.toLowerCase();
        for(int j=1;j<len;j++)
         {
           char  ch=s.charAt(j);

           if(s.charAt(j-1)!=' ')
           {
             ch=Character.toLowerCase((s.charAt(j)));
           }
           else
           {
             ch=Character.toUpperCase((s.charAt(j)));
            }
            s1=s1+ch;
          }
     System.out.println(" "+s1);
  }
}

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