Map three ways to traverse

Package decorator; Import java.util.Collection;  Import Java.util.HashMap;  Import Java.util.Map;  Import Java.util.Map.Entry;  Import Java.util.Set;  Import Org.junit.Before;  Import Org.junit.Test; /** * Three ways for map traversal 1.keySet () 2.values () 3.entrySet () * Three ways to get set, you can use foreach or iterator, cannot use for, because the data structure determines the * * @aut                       Hor Administrator * * */public class Mapcycle {map<integer, string> Map;  Ready data @Before public void TestData () {map =                                New Hashmap<> ();                                Map.put (1, "Ling Yi");           Map.put (2, "Ling er");                                Map.put (3, "ling three");                                Map.put (4, "Ling Si");           Map.put (5, "Ling Five");                         }/** Test Three ways, these three methods are finally traversing set, so you can use the foreach or iterator **///Way 1:keyset () method to get to set (key)    @Test public void Testfirst () {                              set<integer> set = Map.keyset ();                                    For (integer integer:set) {System. Out.println (Map.get (integer));                          }}//Way 2:values () method gets to collection (value) @Test public void Testsecond () {collection<string& Gt                                   Collection = Map.values ();                                    for (string string:collection) {System. OUT.PRINTLN (String); }}//Mode 3:entryset () method gets to set<entry<key,value& gt;> @Test public void Testthird () {set<e                                    Ntry<integer, string>> entries = Map.entryset (); for (Entry<integer, string> entry:entries) {System. Out.println (Entry.getvalue (                                            )); }                               }                }

　　

Map three ways to traverse