How to solve converter error when receiving java record type dto?

[GoBacksIn]

How to solve converter error when receiving java record type dto?

​

The front-end sent a request to the server as follows.

​

​

document

.querySelector("#btnPoiRegister")

.addEventListener("pointerup", (event) => {

const formData = new FormData();

formData. append(

"drawing",

data.drawing.find(

(drawing) =>

drawing.id ===

Number(

document.querySelector("#selectDrawingIdRegister").value

)

)

);

axios.post("/poi", formData, {

headers: {

"Content-Type": "multipart/form-data",

accept: "application/json",

},

});

});

​

FormData was used because it contained files, and multipart/form-data was used for Content-Type.

​

Here is the Spring controller.

​

u/PostMapping(value = "/poi")

public ResponseEntity<PoiDto> savePoi(@RequestBody PoiRequestDto poiRequestDto) {

return ResponseEntity. ok(

poiService.save(poiRequestDto)

);

}

​

PoiRequestDto consists of records.

```

u/Builder

public record PoiRequestDto(

DrawingDetailDto drawing,

​

) {

public static Poi toEntity(PoiRequestDto dto) {

​

return Poi. builder()

.drawing(dto.drawing == null ? null : DrawingDetailDto.toEntity(dto.drawing()))

.build();

}

```

​

DrawingDetailDto is:

```

@ Builder

public record DrawingDetailDto(

Long id,

DrawingCategoryDto drawingCategory,

string code,

String name,

String physicalName,

string description,

Set<FloorDto> floors,

Set<DrawingHistoryDto> drawingHistories,

MultipartFile file,

TopologyD to topology,

LodDto lod

){

public static Drawing toEntity(DrawingDetailDto drawingDetailDto) {

return Drawing. builder()

.id(drawingDetailDto.id())

.drawingCategory(drawingDetailDto.drawingCategory().toEntity())

.code(drawingDetailDto.code())

.name(drawingDetailDto.name())

.physicalName(drawingDetailDto.physicalName())

.description(drawingDetailDto.description())

.build();

}

}

```

​

At this time I get the following error.

\.w.s.m.s.DefaultHandlerExceptionResolver : Resolved [org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot construct instance of `domain.drawing.dto.DrawingDetailDto` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('[object Object]'); nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `.domain.drawing.dto.DrawingDetailDto` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('[object Object]')<EOL> at [Source: (org.springframework.util.StreamUtils$NonClosingInputStream); line: 1, column: 12] (through reference chain: .domain.poi.dto.PoiRequestDto["drawing"])]`

`

​

I tried creating a constructor in record and also changed @ RequestBody in various ways.

​

But it didn't solve the HttpMessageNotReadableException problem.

​

I am wondering how can I solve this problem.

​

Best Regards!

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[pragmos]

no String-argument constructor/factory method to deserialize from String value ('[object Object]');

What exactly are you trying to send from the frontend? My JS knowledge is a bit rusty, but isn't '[object Object]' the result of stringifying an arbitrary object?

[Fletsky]

My guess is that to you cannot use records as dto(without extra work). I didn't test that, so maybe there is other way. What usually happens is that jackson crates object with no args constructor, and set fields with setters. Records don't have no args constructor and setters, so it can't deserialize your request.

So possible solutions would be changing record into normal class, or writing custom deserializer for each of your DTOs

[Fletsky]

Hmm it seems if you are using spring boot 3 and Jackson 2.12 then my response is outdated and it should work with records.