Several methods of Java traversal List,map,vector,set

About the difference of list,map,set reference http://www.cnblogs.com/qlqwjy/p/7406573.html

1. Traversing the list

@Test Public voidtestlist () {List<Integer> list =NewArraylist<integer>(); List.add (1); List.add (2); System.out.println ("-------------------List------------------"); System.out.println ("-------Enhanced for loop list----");  for(inti:list)        {System.out.println (i); } System.out.println ("-------for loop list----");  for(inti = 0; I < list.size (); i++) {System.out.println (List.get (i)); } System.out.println ("-------iterators traverse list----"); Iterator<Integer> iterator =List.iterator ();  while(Iterator.hasnext ()) {System.out.println (Iterator.next ()); }    }

Results:

-------------------list-------------------------enhanced for loop list-----------for loop list-----------iterator traverse list----12

2. Traverse the Map

@Test Public voidTestMap () {Map<integer, string> m =NewHashmap<integer, string>(); M.put (1, "s"); M.put (2, "s"); M.put (3, "s"); M.put (4, "s"); System.out.println ("-------------------Map------------------"); System.out.println ("--------Loop through key values---------");  for(Map.entry<integer, string>Entry:m.entryset ()) {System.out.println (Entry.getkey ()+ "   " +Entry.getvalue ()); } System.out.println ("--------is based on the key value (the key is exactly an integer)---------");  for(inti = 0; I < m.size (); i++) {System.out.println (M.get (i+ 1)); }    }

-------------------Map--------------------------Loop-through key values---------1   s 2   s3   s 4   s-----------------ssss based on the key value (the key is exactly an integer)

3. Traversing set

@Test Public voidTestset () {Set<Integer> set =NewHashSet (); Set.add (1); Set.add (2); System.out.println ("-------------------Set------------------"); System.out.println ("-------Enhance for loop----");  for(intI:set)        {System.out.println (i); } System.out.println ("-------Iterator traversal----"); Iterator<Integer> iterator =Set.iterator ();  while(Iterator.hasnext ()) {System.out.println (Iterator.next ()); }    }

-------------------set-------------------------enhanced for loop-----------Iterator traversal----12

4. Traversing vectors

@Test Public voidTestvector () {System.out.println ("-------------------Vector------------------"); Vector<String> v =NewVector<string>(); V.add ("SSS"); V.add ("Sssss"); System.out.println ("-------normal for loop----");  for(inti = 0; I < v.size (); i++) {System.out.println (V.get (i)); } System.out.println ("-------Enhance for loop----");  for(String x:v) {System.out.println (x); } System.out.println ("-------Iterator traversal----"); Iterator<String> iterator =V.iterator ();  while(Iterator.hasnext ()) {System.out.println (Iterator.next ()); }    }

-------------------vector-------------------------normal for loop----ssssssss-------enhanced for loop----ssssssss -------Iterator traversal----ssssssss

Several methods of Java traversal List,map,vector,set