Several traversal methods of map

public static void Main (string[] args) {

map<string, string> map = new hashmap<string, string> ();
Map.put ("1", "value1");
Map.put ("2", "value2");
Map.put ("3", "Value3");

The first type: Universal use, two-time value
System.out.println ("Traverse key and value by Map.keyset");
For (String Key:map.keySet ()) {
System.out.println ("key=" + key + "and value=" + map.get (key));
}

The second Kind
System.out.println ("Traverse key and value by Map.entryset using iterator");
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 ());
}

The third type: recommended, especially when the capacity is large
System.out.println ("Traverse key and value through Map.entryset");
For (map.entry<string, string> entry:map.entrySet ()) {
System.out.println ("key=" + entry.getkey () + "and value=" + entry.getvalue ());
}

Fourth type
System.out.println ("Traverse all the value through Map.values (), but cannot traverse key");
For (String v:map.values ()) {
System.out.println ("value=" + V);
}
}

Several traversal methods of map