lCollection接口:单列集合的根接口
•主要方法
-boolean add(E e)
-boolean remove(Object o)
-void clear()
-boolean contains(Object o)
-boolean isEmpty()
-int size()
•主要方法2
-boolean addAll(Collection c)
-boolean removeAll(Collection c)
-boolean containsAll(Collection c)
-boolean retainAll(Collection c)
•返回迭代器方法
-Iterator<E> iterator()
lIterator接口:单列集合的迭代器。迭代器会像地震搜救队的方式一样去遍历集合中的每一个元素。
•主要方法
-boolean hasNext()
-E next()
•使用固定格式:
•格式一:
Collection c = new ArrayList(); Iterator it = c.iterator(); while(it.hasNext()){ System.out.println(it.next()); } •格式二:
for(Interator it =c.iterator();it.hasNext();){ System.out.println(it.next()); }
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