Java实现字符串单词反转

 public static void reverse(char[]arr,int i ,int j) {
    //每个单词首位交换
    while (i < j){
      swap(arr, i ++, j --);
    }
  }
  public static void swap(char[] arr, int i, int j){
    char brr = arr[i];
    arr[i] = arr[j];
    arr[j] = brr;

  }
 public static void rev(String word){
    char[] a = word.toCharArray();
    int n = a.length;
    reverse(a,0,n-1);
    for (int i=0; i<n; ++i) {
      int j = i;
      for (; j<n && a[j]!=' '; j++);
      reverse(a, i, j-1);
      i = j;
    }
    System.out.println(a);
  }

public static void main(String[] args) {
  String s = "hello world ni hao shi jian";
  String[] arr = s.split(" ");
  int i=0, j=arr.length-1;
  while (i < j) {
    String x = arr[i];
    arr[i] = arr[j];
    arr[j] = x;
    i ++;j--;
  }
  String res="";
  for (int k=0; k<arr.length; ++k) {
    res = res + arr[k];
    if (k != arr.length-1) res += " ";
  }
  System.out.println(res);
}