map是雙列集合(hashMap treeMap)
HashMap<Integer, String> hm = new HashMap(); hm.put(1, "第一"); hm.put(2, "第二"); hm.put(3, "第三"); hm.put(4, "第四"); hm.put(5, "第五"); hm.put(6, "第六");
方式一:
keySet():拿到所有key的集合
Set<Integer> integers = hm.keySet();
get():遍歷key集合,根據key,拿到對應的value值
for (Integer i : integers) { String s = hm.get(i); System.out.println("xd----key==" + i + "---value==" + s); }
方式二:
entrySet():拿到所有鍵值對的地址值
Set<Map.Entry<Integer, String>> entries = hm.entrySet();
遍歷地址集合返回的是Map對象:拿到每個map的key和value
for (Map.Entry<Integer, String> map : entries) { String value = map.getValue(); Integer key = map.getKey(); }