map的幾種遍歷方法
private Hashtable<String, String> emails = new Hashtable<String, String>();
//方法一: 用entrySet()
Iterator it = emails.entrySet().iterator();
while(it.hasNext()){
Map.Entry m=(Map.Entry)it.next();
logger.info("email-" + m.getKey() + ":" + m.getValue());
}
// 方法二:jdk1.5支持,用entrySet()和For-Each循環()
for (Map.Entry<String, String> m : emails.entrySet()) {
logger.info("email-" + m.getKey() + ":" + m.getValue());
}
// 方法三:用keySet()
Iterator it = emails.keySet().iterator();
while (it.hasNext()){
String key;
key=(String)it.next();
logger.info("email-" + key + ":" + emails.get(key));
}
// 方法五:jdk1.5支持,用keySEt()和For-Each循環
for(Object m: emails.keySet()){
logger.info("email-" + m+ ":" + emails.get(m));
}
另外 我們可以先把hashMap 轉為集合Collection,再叠代輸出,不過得到的對象
Map aa = new HashMap();
aa.put("tmp1", new Object()); //追加 替換用同樣的函數.
aa.remove("temp1"); //刪除
for (Iterator i = aa.values().iterator(); i.hasNext(); ) {
Object temp = i.next();
} //遍歷
map的幾種遍歷方法