Best practice to send response in spring boot

Question

I\'m coding REST Api-s in spring boot. I want to make sure that my code is readable to front-end developers using swagger API development tool (Swagger). For example

Answer 1

I would recommend to do it like this .

@GetMapping("/getOne")
public Response getOne(@RequestParam String id) {
        ResponseEntity<Branch> resbranch;
        ResponseEntity<FindError> reserror;
        try {
            resbranch=new ResponseEntity<Branch>(branchService.getOne(id), HttpStatus.OK);
            return Response.status(200).entity(resbranch).build();

        } catch (Exception e) {
            reserror=new ResponseEntity<FindError>(new FindError(e.getMessage()), HttpStatus.BAD_REQUEST);
            return Response.status(400).entity(reserror).build();
        }
    }

200 is for OK and 400 is for bad request. Here there wont be anymore ambiguous types..

Answer 2

First of all you should follow the best practices of a RESTful API . Don't use verbs, instead use nouns as URL.So instead of @GetMapping("/getOne") , you can write it as @GetMapping("/branch/{id}") . You can refer this blog https://blog.mwaysolutions.com/2014/06/05/10-best-practices-for-better-restful-api/

@2ndly , Don't return a generic type as ? , instead you can user the specific type , here as Branch and do central exception handling . The following code snippet can help you :

@GetMapping("/branch/{id}")
public ResponseEntity<Branch> getBranch(@Pathvariable String id) {
{
    Branch branch = branchService.getOne(id);

    if(branch == null) {
         throw new RecordNotFoundException("Invalid Branch id : " + id);
    }
    return new ResponseEntity<Branch>(branch, HttpStatus.OK);
}

RecordNotFoundException.java

@ResponseStatus(HttpStatus.NOT_FOUND)
public class RecordNotFoundException extends RuntimeException
{
    public RecordNotFoundException(String exception) {
        super(exception);
    }
}

CustomExceptionHandler.java

@ControllerAdvice
public class CustomExceptionHandler extends ResponseEntityExceptionHandler
{
    @ExceptionHandler(Exception.class)
    public final ResponseEntity<Object> handleAllExceptions(Exception ex, WebRequest request) {
        List<String> details = new ArrayList<>();
        details.add(ex.getLocalizedMessage());
        ErrorResponse error = new ErrorResponse("Server Error", details);
        return new ResponseEntity(error, HttpStatus.INTERNAL_SERVER_ERROR);
    }

    @ExceptionHandler(RecordNotFoundException.class)
    public final ResponseEntity<Object> handleRecordNotFoundException(RecordNotFoundException ex, WebRequest request) {
        List<String> details = new ArrayList<>();
        details.add(ex.getLocalizedMessage());
        ErrorResponse error = new ErrorResponse("Record Not Found", details);
        return new ResponseEntity(error, HttpStatus.NOT_FOUND);
    }
}

ErrorResponse.java

public class ErrorResponse
{
    public ErrorResponse(String message, List<String> details) {
        super();
        this.message = message;
        this.details = details;
    }

    private String message;

    private List<String> details;

    //Getter and setters
}

The above class handles multiple exceptions including RecordNotFoundException and you can also customize for payload validations too.

Test Cases :

1) HTTP GET /branch/1 [VALID]

HTTP Status : 200

{
    "id": 1,
    "name": "Branch 1",
    ...
}
2) HTTP GET /branch/23 [INVALID]

HTTP Status : 404

{
    "message": "Record Not Found",
    "details": [
        "Invalid Branch id : 23"
    ]
}