Java Basic Knowledge Hardening Collection Framework note 18:list Collection-specific Listiterator iterators

1. Listiterator (List iterator):

Listiterator Listiterator (): A list collection-specific iterator

2. code example:

1  Packagecn.itcast_04;2 3 Importjava.util.ArrayList;4 ImportJava.util.Iterator;5 Importjava.util.List;6 ImportJava.util.ListIterator;7 8 /*9 * List iterator:Ten * Listiterator listiterator (): List collection-specific iterator One * The iterator inherits the iterator iterator, so you can use the Hasnext () and Next () methods directly.  A  *  - * Unique Features: - * Object Previous (): Gets the previous element  the * boolean hasprevious (): Determine if there are elements  -  *  - * Note: Listiterator can implement reverse traversal, but must first forward traversal, in order to reverse the traversal, so generally meaningless, not used .  -  */ +  Public classListiteratordemo { -      Public Static voidMain (string[] args) { +         //To Create a list collection Object AList List =NewArrayList (); atList.add ("Hello"); -List.add ("World"); -List.add ("Java"); -  -         //listiterator listiterator () -Listiterator lit = List.listiterator ();//sub-class object in         //While (Lit.hasnext ()) { -         //string s = (string) lit.next (); to         //System.out.println (s); +         // } -         //System.out.println ("-----------------"); the          *         //System.out.println (Lit.previous ()); $         //System.out.println (Lit.previous ());Panax Notoginseng         //System.out.println (Lit.previous ()); -         //nosuchelementexception the         //System.out.println (Lit.previous ()); +  A          while(Lit.hasprevious ()) {//no print, just start (Pointer to collection list first element address first element before one is not), so there is nothing to print out  theString s =(String) lit.previous (); + System.out.println (s); -         } $System.out.println ("-----------------"); $  -         //iterators -Iterator it =list.iterator (); the          while(It.hasnext ()) { -String s =(String) It.next ();Wuyi System.out.println (s); the         } -System.out.println ("-----------------"); Wu  -     } About}

The results are as follows:

Java Basic Knowledge Hardening Collection Framework note 18:list Collection-specific Listiterator iterators