How to filter a list with common string and group to a new list-CodePudding

I have a List<String> which consist of a json string. example below has 5 items in the list. Is there any simple way to extract common class (ex. Biology, Mathematics, History) from the list and group it and create a new List for all the common class.

{"name":"Alex","age":"31","class":"Biology","parents":{"father":"Robert","mother":"Mary"}}
{"name":"John","age":"34","class":"Mathematics","parents":{"father":"Remi","mother":"Maya"}}
{"name":"Rita","age":"27","class":"History","parents":{"father":"Shankar","mother":"Anita"}}
{"name":"Sonia","age":"27","class":"Biology","parents":{"father":"Mathew","mother":"Lucy"}}
{"name":"Caroline","age":"29","class":"Mathematics","parents":{"father":"David","mother":"Christine"}}

expected:

List newList1

{"name":"Alex","age":"31","class":"Biology","parents":{"father":"Robert","mother":"Mary"}}
{"name":"Sonia","age":"27","class":"Biology","parents":{"father":"Mathew","mother":"Lucy"}}

List newList2

{"name":"John","age":"34","class":"Mathematics","parents":{"father":"Remi","mother":"Maya"}
{"name":"Caroline","age":"29","class":"Mathematics","parents":{"father":"David","mother":"Christine"}}

List newList3

{"name":"Rita","age":"27","class":"History","parents":{"father":"Shankar","mother":"Anita"}}

CodePudding user response：

Create a DTO representing your JSON structure (e.g. class YourDTO)
Use Jackson's ObjectMapper to parse your JSON string to instances of the Java class
Use Stream API and groupingBy collector to create a Map<String, List<YourDTO>>, by grouping on the Category of the parsed object
Assign the required categories to separate variables or call .values() on the map to get a List<List<YourDTO>>.