Spring MVC: Complex object with an array field as GET @RequestParam

Question

My issue is similar to this one: I don't want to have a lot of parameters in my controller, so I moved them all to a separate class.

class FilterRequest(
    val storeCode: List<String>,
    val extOrderId: List<String>,
    val name: String,    
    
    @DateTimeFormat(iso = DateTimeFormat.ISO.DATE)
    val createDate: LocalDate?,
    
    @DateTimeFormat(iso = DateTimeFormat.ISO.DATE)
    val lastModifiedDate: LocalDate?
)

Controller

@GetMapping
fun getByFilters(request: FilterRequest, pageable: Pageable){...}

If I send a request like this

?extOrderId=200600774995,200600774

all values are stored a single cell.

And If I send it like this

?extOrderId=200600774995&extOrderId=200600774

values go to separate cells.

Is there any way to pass multiple values as a parameter and have these values stored in separate cells?

Answer 1

I was able to fix this issue by changing val to var in the FilterRequest class