Hashmap -- traverse ---- keyset -- entryset

 

Import Java. util. *; import Java. util. map. entry; class person implements comparable <person> {public string name; Public int age; Public Person (string name, int age) {This. name = Name; this. age = age;} Public String getname () {return name;} public int getage () {return age;} @ overridepublic int hashcode () {return name. hashcode () + age ;}@ overridepublic Boolean equals (Object OBJ) {If (! (OBJ instanceof person) throw new classcastexception ("inconsistent types"); person = (person) OBJ; return this. name. equals (person. name) & (this. age = person. age) ;}@ overridepublic int compareto (person p) {int num = (New INTEGER (AGE )). compareto (New INTEGER (P. age); If (num = 0) return name. compareto (P. name); Return num ;}@ overridepublic string tostring () {return name + ":" + age ;}} public class maptest {public static void main (string ARGs []) {hashmap <person, string> hashmap = new hashmap <person, string> (); hashmap. put (new person ("boy", 20), "Jiangsu"); hashmap. put (new person ("girl", 19), "Henan"); hashmap. put (new person ("person", 49), "China"); // The following output uses the keyset method set <person> keyset = hashmap. keyset (); For (iterator <person> it = keyset. iterator (); it. hasnext ();) {person P = it. next (); system. out. println (P. getname () + ":" + P. getage () + ":" + hashmap. get (p);} // use the entryset method set <entry <person, string> entryset = hashmap. entryset (); For (iterator <entry <person, string> it = entryset. iterator (); it. hasnext ();) {entry <person, string> item = it. next (); system. out. println (item. getkey () + ":" + item. getvalue () ;}}2011/10/28 14:27:45