用Java将字符串的首字母转换大小写

  //首字母转小写  public static String toLowerCaseFirstOne(String s){    if(Character.isLowerCase(s.charAt(0)))      return s;    else      return (new StringBuilder()).append(Character.toLowerCase(s.charAt(0))).append(s.substring(1)).toString();  }  //首字母转大写  public static String toUpperCaseFirstOne(String s){    if(Character.isUpperCase(s.charAt(0)))      return s;    else      return (new StringBuilder()).append(Character.toUpperCase(s.charAt(0))).append(s.substring(1)).toString();  }