????Map????
????1.????ü???洢????????????????檔???????????????
????2.???÷?????
????1.????v  put(k key ?? v value); ???????????????????????С?
????void putAll(Map<? extends k??? extends v> m) ;?????????н??????????????????????
????2.?????void clear();  ??????
????v remove(Object key); ???????е?????????????????
????3.?ж??containsKey(Object key) ?ж???????????key??????У?????true??
????contaninValue(Object value) ?ж???????????value
????4.?????get(Object key);
????size();
????values();
????entrySet();
????keySet();
????Map??????????????
????|---Hashtable???????????????????ù?????????????????κη?null????????????????????ü?????????????? Jdk1.0 Ч???
????|--HashMap?????????????????????????null???null?????ü???????????? Jdk1.2 Ч???
????|--TreeMap?????????????????????????????????????map?????е??????????
??????Set????
???????Set??????????Map?????
??????????????????????????????????????????????
????map?????????????????
????1.keySet????map?????е??????Set????????set?????????????????????????????????е?????????get???????????????????????
????Map??????????????map???????set?????????????????????
????2.Set<Map.Entry<k??v>>  entrySet????map?????е????????????set?????У??????????????????????map.entry.
????Map.Entry  ???Entry??????????????Map????е???????????
??????????????????????
???????
????a.Map?????д??????????????????????????????Map??????????????????????????????????????????????
????b.??????????????????????Map?????е???????????????????????

 

package Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;
import java.util.Map.Entry;
public class HashMapDemo {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
entrySetMethod();
}
//????keySet??????????map?????е????
public static void keySetMethod(){
//???????HashMap???????????????????????String??????
HashMap<String??String> hm = new HashMap<String??String>();
hm.put("01"??"zhangsan01");
hm.put("02"??"zhangsan02");
hm.put("03"??"zhangsan03");
hm.put("04"??"zhangsan04");
Set<String> keyset = hm.keySet();
for(Iterator<String> it =keyset.iterator();it.hasNext();){
String key =it.next();
String value = hm.get(key);
System.out.println("key: "+key+" "+"value:"+value);
}
}
public static void entrySetMethod(){
HashMap<String??String> hm = new HashMap<String??String>();
hm.put("01"??"zhangsan01");
hm.put("02"??"zhangsan02");
hm.put("03"??"zhangsan03");
hm.put("04"??"zhangsan04");
Set<Entry<String?? String>> entry=hm.entrySet();
for(Iterator<Entry<String?? String>> it =entry.iterator();it.hasNext();){
Entry<String?? String> en = it.next();
System.out.println(en.getKey()+"  "+en.getValue());
}
}
}