public static void main(String[] args) throws IOException {
    String words = "this is a test";

    System.out.println(Arrays.asList(words.split(" ")).stream().reduce("",(a, b)->(a + " " + b.substring(0, 1).toUpperCase() + b.substring(1))));


}

}

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;
}

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);
  }
}

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);

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();
}

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();
}