four ways of MAP traversal

  map<string, string> map = new hashmap<string, string> ();
  Map.put ("Key1", "value1");
  Map.put ("Key2", "value2");
  
  Map.put ("Key3", "value3");
  The first: universal use, two times value System.out.println ("Through the Map.keyset traversal key and Value:");
  For (String Key:map.keySet ()) {System.out.println ("key=" + key + "and value=" + map.get (key));
  }//Second System.out.println ("Traverse key and value using iterator via Map.entryset:");
  Iterator<map.entry<string, string>> it = Map.entryset (). iterator ();
   while (It.hasnext ()) {map.entry<string, string> Entry = It.next ();
  System.out.println ("key=" + entry.getkey () + "and value=" + entry.getvalue ());
  //Third: recommended, especially when capacity is large System.out.println ("Traverse key and value via Map.entryset"); For (map.entry<string, string> entry:map.entrySet ()) {System.out.println ("key=" + entry.getkey () + "and Valu")
  E= "+ entry.getvalue ());
  }//Fourth System.out.println ("Traverse all value through Map.values (), but cannot traverse key"); For (String v:map.values ()) {System.Out.println ("value=" + V);
 }