List的三种遍历

1.foreach循环遍历

for (Object object : list) {            System.out.print(object+" ");        }

2.Iterator迭代器遍历

Iterator iterator = list.iterator();        while (iterator.hasNext()) {            System.out.print(iterator.next()+" ");        }

3.ListIterator迭代器遍历

ListIterator iterator2 = list.listIterator();        while (iterator2.hasNext()) {            System.out.print(iterator2.next()+" ");        }

ListIterator迭代器具有向前遍历的方法，以及在迭代位置添加对象的方法

iterator2.add(4);        while(iterator2.hasPrevious()) {            System.out.print(iterator2.previous()+" ");        }