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()+" ");
        }