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JDK1.4ÖÐ
Map map = new HashMap();
Iterator it = map.entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
Object key = entry.getKey();
Object value = entry.getValue();
}
JDK1.5ÖÐ,Ó¦ÓÃÐÂÌØÐÔFor-EachÑ­»·
Map m = new HashMap();
for(Object o : map.keySet()){
map.get(o);
}
·µ»ØµÄ set ÖеÄÿ¸öÔªËض¼ÊÇÒ»¸ö Map.Entry ÀàÐÍ¡£
private Hashtable<String, String> emails = new Hashtable<String, String>();
  ÁíÍâ ÎÒÃÇ¿ÉÒÔÏÈ°ÑhashMap תΪ¼¯ºÏCollection£¬ÔÙµü´úÊä³ö£¬²»¹ýµÃµ½µÄ¶ÔÏó
//·½·¨Ò»: ÓÃentrySet()
Iterator it = emails.entrySet().iterator();
while(it.hasNext()){
Map.Entry m=(Map.Entry)it.next();
logger.info("email-" + m.getKey() + ":" + m.getValue());
}

// ·½·¨¶þ£ºjdk1.5Ö§³Ö£¬ÓÃentrySet()ºÍFor-EachÑ­»·()
for (Map.Entry<String, String> m : emails.entrySet()) {

logger.info("email-" + m.getKey() + ":" + m.getValue());
}

// ·½·¨Èý£ºÓÃkeySet()
Iterator it = emails.keySet().iterator();
while (it.hasNext()){
String key;
key=(String)it.next();
logger.info("email-" + key + ":" + emails.get(key));
}
// ·½·¨Î壺jdk1.5Ö§³Ö£¬ÓÃkeySEt()ºÍFor-EachÑ­»·
for(Object m: emails.keySet()){
logger.info("email-" + m+ ":" + emails.get(m));
}
      Map    aa    =    new    HashMap();     
 aa.put("tmp1",    new    Object());    
  //×·¼Ó      Ìæ»»ÓÃͬÑùµÄº¯Êý.     
aa.remove("temp1");                       
 //ɾ³ý     
 for    (Iterator    i    =    aa.values().iterator