public static void main(String[] args) {
    char[] chars= new String("How old are you !? I don't understand").toCharArray();
    System.out.println("the first:");
    System.out.println(chars);
     
    reverseWords(chars); //主要方法
     
    System.out.println("the second:");
    System.out.println(chars);
  }
 
   
  /**
   * 会将数组里面的单词 倒序排列 例如 how old are you -> you are old how
   * @param chars
   */
  public static void reverseWords(char[] chars) {
    reverseChars(chars,0,chars.length-1);
    int begin = -1;
    int end = 0;
    for(int i=0;i<chars.length;i++){
      char c = chars[i];
      if((c>='a'&&c<='z')||(c>='A'&&c<='Z')||c=='\''){ //简单的判断了一下是否是连续的单词
        if(begin==-1){
          begin = i;
          end=i;
        }else{
          end=i;
          if(i==chars.length-1){
            reverseChars(chars,begin,end);
          }
        }
      }else{
        if(begin!=-1){
          reverseChars(chars,begin,end);
          begin=-1;
          end=0;
        }
      }
    }
  }
 
  /**
   * 将char 一定范围内的 字符 倒序排列 例如   hello -> olleh
   * @param chars 数组
   * @param begin 开始位置
   * @param end  结束位置
   */
  public static void reverseChars(char[] chars, int begin, int end) {
    while(end>begin){
      char c = chars[begin];
      chars[begin] = chars[end];
      chars[end] = c;
      begin++;
      end--;
    }
  }