获取LinkedHashMap的中间个对象

LinkedHashMap是一个有序的HashMap，可以通过迭代器或者转换成List来获取其中间的元素。

方法一：使用迭代器

LinkedHashMap<Integer, String> map = new LinkedHashMap<>();
map.put(1, "a");
map.put(2, "b");
map.put(3, "c");
map.put(4, "d");
Iterator<Map.Entry<Integer, String>> it = map.entrySet().iterator();
int i = 0;
int mid = map.size() / 2;
while (it.hasNext()) {
    Map.Entry<Integer, String> entry = it.next();
    if (i == mid) {
        System.out.println(entry.getValue());
        break;
    }
    i++;
}

方法二：转换成List

LinkedHashMap<Integer, String> map = new LinkedHashMap<>();
map.put(1, "a");
map.put(2, "b");
map.put(3, "c");
map.put(4, "d");
List<Map.Entry<Integer, String>> list = new ArrayList<>(map.entrySet());
int mid = list.size() / 2;
System.out.println(list.get(mid).getValue());