Java Learning Notes < >iterator sub-interface of the collection framework Listiterator

1 Importjava.util.ArrayList;2 ImportJava.util.Iterator;3 Importjava.util.List;4 5  Public classTest3 {6 7      Public Static voidMain (string[] args) {8List List =NewArrayList ();9         TenList.add ("ABC1"); OneList.add ("ABC2"); AList.add ("ABC3"); -List.add ("ABC4"); -          theIterator it =list.iterator (); -          while(It.hasnext ()) { -Object obj = It.next ();//java.util.ConcurrentModificationException -              +             if(Obj.equals ("ABC2")){ -List.add ("abc9");//In the iterator process, do not use the collection manipulation elements, prone to exceptions.  +                                       //You can use the subinterface listiterator of the iterator interface to do more with the elements in the iteration A             } at             Else -System.out.println ("Next:" +obj); -         } - System.out.println (list); -  -     } in  -}

1 Importjava.util.ArrayList;2 Importjava.util.List;3 ImportJava.util.ListIterator;4 5  Public classTest3 {6 7      Public Static voidMain (string[] args) {8List List =NewArrayList ();9         TenList.add ("ABC1"); OneList.add ("ABC2"); AList.add ("ABC3"); -List.add ("ABC4"); -          theSystem.out.println ("list:" +list); -          -Listiterator it = List.listiterator ();//gets the object of the list iterator -                                               //it can be implemented in the iterative process to complete the deletion and modification of elements +                                                //Note: Only the list collection has this iteration function -          +System.out.println ("Hasnext:" +it.hasprevious ());//returns the result of the element before the current position in the list. True or False A          at          while(It.hasnext ()) { -Object obj =It.next (); -              -             if(Obj.equals ("ABC2")){ -It.set ("abc9");//replaces the last element returned by next or previous with the specified element (optional action).  -             } in         } -          toSystem.out.println ("list:" +list); + System.out.println (); -          theSystem.out.println ("Hasnext:" +It.hasnext ()); *System.out.println ("Hasnext:" +it.hasprevious ()); $ System.out.println ();Panax Notoginseng          -          while(It.hasprevious ()) the         { +System.out.println ("Previous:" +it.previous ()); A         } the System.out.println (); +          -System.out.println ("list:" +list); $     } $  -}

Java Learning Notes < >iterator sub-interface of the collection framework Listiterator