Question

      ArrayList<String> aList = new ArrayList<String>();

        //Add elements to ArrayList object
        aList.add("1");
      aList.add("2");
       aList.add("3");
        aList.add("4");
        aList.add("5");

        //Get an object of ListIterator using listIterator() method
        ListIterator listIterator = aList.listIterator();

        //Traverse in forward direction  
        System.out.println("Traversing ArrayList in forward directio using ListIterator");
        while(listIterator.hasNext())
          System.out.println(listIterator.next());

        /*
          Traverse the ArrayList in reverse direction using hasPrevious and previous
          methods of ListIterator. hasPrevious method returns true if
          ListIterator has more elements to traverse in reverse direction.
          Previous method returns previous element in the list.
        */
        System.out.println("Traversing ArrayList in reverse direction using ListIterator");
        while(listIterator.hasPrevious())
          System.out.println(listIterator.previous());

      }
    }

在上面的代码列表中，数组值反向打印。但是我需要使用相同的方法来反转单个数组句子。例如：aList.add（“你好世界”）;这里只有一个字符串。但需要像“世界问候”一样颠倒这个词。

Answer 1

您可以split String成String（s）数组，将其转换为List<String> Arrays.asList然后reverse那个。像，

String str = "hello world";
List<String> al = Arrays.asList(str.split("\\s+"));
Collections.reverse(al);
for (String s : al) {
    System.out.print(s + " ");
}
System.out.println();

输出（按要求）

world hello

或者，修改您的ListIterator（不应使用raw types）。像，

String str = "hello world";
List<String> al = Arrays.asList(str.split("\\s+"));
ListIterator<String> listIterator = al.listIterator();

我得到了

Traversing ArrayList in forward directio using ListIterator
hello
world
Traversing ArrayList in reverse direction using ListIterator
world
hello

如何使用hasprevious（）方法使用java来反转单词？

1 个答案: