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();
    }
}

package corejava.string.intern;

import java.io.DataInputStream;

import java.util.ArrayList;

/*
 * wap to accept only 3 sentences and convert first character of each word into upper case
 */

public class Accept3Lines_FirstCharUppercase {

    static String line;
    static String words[];
    static ArrayList<String> list=new ArrayList<String>();

    /**
     * @param args
     */
    public static void main(String[] args) throws java.lang.Exception{

        DataInputStream read=new DataInputStream(System.in);
        System.out.println("Enter only three sentences");
        int i=0;
        while((line=read.readLine())!=null){
            method(line);       //main logic of the code
            if((i++)==2){
                break;
            }
        }
        display();
        System.out.println("\n End of the program");

    }

    /*
     * this will display all the elements in an array
     */
    public static void display(){
        for(String display:list){
            System.out.println(display);
        }
    }

    /*
     * this divide the line of string into words 
     * and first char of the each word is converted to upper case
     * and to an array list
     */
    public static void method(String lineParam){
        words=line.split("\\s");
        for(String s:words){
            String result=s.substring(0,1).toUpperCase()+s.substring(1);
            list.add(result);
        }
    }

}

试试这个非常简单的方法

示例givenString="ram是好孩子"

public static String toTitleCase(String givenString) {
    String[] arr = givenString.split(" ");
    StringBuffer sb = new StringBuffer();

    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();
}  

输出将是:公羊是好孩子

因为没有人使用regexp，所以我们使用regexp。这个解决方案只是为了好玩。:)(更新:实际上我刚刚发现有一个regexp的答案，无论如何，我想把这个答案留在原地，因为它更好看:)):

public class Capitol 
{
    public static String now(String str)
    {
        StringBuffer b = new StringBuffer();
        Pattern p = Pattern.compile("\\b(\\w){1}");
        Matcher m = p.matcher(str);
        while (m.find())
        {
            String s = m.group(1);
            m.appendReplacement(b, s.toUpperCase());
        }
        m.appendTail(b);
        return b.toString();
    }
}

使用

Capitol.now("ab cd"));
Capitol.now("winnie the Pooh"));
Capitol.now("please talk loudly!"));
Capitol.now("miles o'Brien"));

worddutil .capitalize(str) (from apache common -text)

(注意:如果你需要“fOO BAr”变成“fOO BAr”，那么用大写的(..)代替)

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);
}