根据两个值对地图列表进行排序

Question

Here is the initialization code:

List<Map<String, Object>> list = new ArrayList<>();

Map<String, Object> map1 = new HashMap<>();
Map<String, Object> map2 = new HashMap<>();
Map<String, Object> map3 = new HashMap<>();
Map<String, Object> map4 = new HashMap<>();
Map<String, Object> map5 = new HashMap<>();

map1.put("Age", 23);
map2.put("Age", 24);
map3.put("Age", 25);
map4.put("Age", 23);
map5.put("Age", 24);

map1.put("Name", "Rohan");
map2.put("Name", "Shyam");
map3.put("Name", "George");
map4.put("Name", "Ram");
map5.put("Name", "Sam");

list.add(map1);
list.add(map2);
list.add(map3);
list.add(map4);
list.add(map5);

Now, I want to sort the list based on the 'Age' value, and then for each same 'Age' values, sort again based on the 'Name' value.

So, my required output is:

{Age=23, Name=Ram}

{Age=23, Name=Rohan}

{Age=24, Name=Sam}

{Age=24, Name=Shyam}

{Age=25, Name=George}

I am able to do the first sorting, but not able to perform the second one.

Answer 1

You could implement a custom Comparator based on those two values:

list.sort(Comparator.comparing((Map<String, Object> map) -> (Integer) map.get("Age"))
                    .thenComparing((Map<String, Object> map) -> (String) map.get("Name"))
);