1.如果当前单个线程在更改容器(add, delete...),那么迭代的时候采用iterator.remove()方法可以确保迭代器在查找next的时候,指针不会丢失。 while(iterator.hasNext() { Object item = iterator.next(); iterator.remove(); //Important! 避免ConcurrentModificationException ... } 2.如果当前有多个线程在对容器进...
List<String> list = List.of("Apple","Orange","Pear");for(String s : list) { System.out.println(s); } 实际上,Java编译器并不知道如何遍历List。上述代码能够编译通过,只是因为编译器把for each循环通过Iterator改写为了普通的for循环: for(Iterator<String> it =list.iterator(); it.hasNext(); )...
list.add("ghi");for(Iterator<String> it=list.iterator();it.hasNext();) { System.out.println(it.next()); } } 执行结果: 回到顶部 二、ArrayList的Iterator实现 privateclass Itrimplements Iterator<E> {int cursor;//index of next element to returnint lastRet = -1;//index of last element r...
Unlike the other abstract collection implementations, the programmer does not have to provide an iterator implementation; the iterator and list iterator are implemented by this class, on top of the “random access” methods: get(int), set(int, E), add(int, E) and remove(int). The documen...
java Iterator.hasNext 用if还是while is a 代表的是类之间的继承关系,比如PC机是计算机,工作站也是计算机。PC机和工作站是两种不同类型的计算机,但都继承了计算机的共同特性。因此在用 Java语言实现时,应该将PC机和工作站定义成两种类,均继承计算机类。 has a 代表的是对象和它的成员的从属关系。同一种类的对象,...
iterator = list.iterator(); while (iterator.hasNext()) { String s = iterator.next(...
1.概念Iterator接口迭代对于我们搞Java的来说绝对不陌生。我们常常使用JDK提供的迭代接口进行Java集合的迭代。Iteratoriterator= list.iterator(); while(iterator.hasNext()){ String string =iterator.next(); //do s 迭代器iterator remove java 迭代
set()- replaces the element returned by eithernext()orprevious()with the specified element Example 1: Implementation of ListIterator In the example below, we have implemented thenext(),nextIndex()andhasNext()methods of theListIteratorinterface in anarray list. ...
(nonstatic) inner class. Note well that each instance contains an implicit* reference to the containing list, allowing it to access the list's members.*/privateclassArrayIteratorimplementsIterator<E>{/** Index of the next element to report. */privateintj=0;// index of the next element to...
hasNext boolean hasNext() Returns true if this list iterator has more elements when traversing the list in the forward direction. (In other words, returns true if next() would return an element rather than throwing an exception.) Specified by: hasNext in interface Iterator<E> Returns: true if...