Springboot组件state在发出新请求时被保留..并发问题？

Question

I have a SpringBoot application which exposes a simple REST-api through @RestController. It takes a file upload, and attempts to read values from the uploaded excel file.

The problem is that the "state" of some component does not seem to get reset on a new request, like it's some kind of concurrency issue.. I can't seem to figure it out. Like when I make a new subsequent request after the first one, values from the previous request is still hanging in the ImportProcessor and subsequent objects, it's not getting reset and I cant figure out why..

The service layer of the application @Autowires a "ImportProcessor" component, which has a lot of fields that are modified through it's methods. Example:

@Component
@NoArgsConstructor
@Slf4j
public class ImportProcessor {

    public static STATE processState = STATE.READY;
    
    @Autowired
    RegulativImporter regulativImporter;

    @Autowired
    DatabaseImporter databaseImporter;

    Sheet strekning;
    Sheet strekning_periode;

    HashMap<Long, TakstkategoriEntity> successfulTakstkategori;
    HashMap<Long, RegulativEntity> successfulRegulativ;
    HashMap<Long, TakstEntity> successfulTakst;

        public ImportJobInfo handleStartProcessingRequest(Workbook workbook) throws FailedToStartProcessingException {
        if (processState == STATE.READY) {
            setProcessState(STATE.IMPORTING);
            ImportJobInfo importJobInfo = startProcessing(workbook);
            cleanUpState();
            return importJobInfo;
        } else {
            throw new FailedToStartProcessingException("Failed to start processing because of insufficient state:",
                processState);
        }
    }

   // Methods that modify and set these objects.. Changes state based on action, initialize hashMaps..
   // Method that inserts part of the Hashmaps to a database using DatabaseImporter
}

Here is the calling Service:

@Service
@Slf4j
public class FergeregisterImportServiceImpl implements FergeregisterImportService {

    @Autowired
    ImportProcessor importProcessor;

    @Override
    public ImportJobInfo startImportJob(MultipartFile file) throws FailedToStartProcessingException {
        
        InputStream excelInputStream;
        Workbook workbook;
        ImportJobInfo importJobInfo = null;

        try {
            excelInputStream = file.getInputStream();
            workbook = new XSSFWorkbook(excelInputStream);
            log.info("Successfully converted Excel inputstream to Apache-POI workbook.");
        } catch (IOException e) {
            log.error(e.getMessage() + " | cause: " + e.getCause());
            throw new FailedToStartProcessingException("Failed to convert Excel inputstream to Apache-POI workbook.",
                STATE.FAILED);
        }

        try {
            importJobInfo = importProcessor.handleStartProcessingRequest(workbook);
        } catch (FailedToStartProcessingException e) {
            log.error(e.getMessage(), importProcessor.getProcessState());
            throw e;
        }

        return importJobInfo;
    }
   // Some other methods..
}

If I dont @Autowire the ImportProcessor, it works fine and I dont have the concurrency issues. But then it seems absolutely impossible for the ImportService to call the @Autowired DatabaseImporter which is the CrudRepository interface

If only I could make sure that the ImportProcessor had a fresh start on each new request, everything would work as intended. I really hope I can get some tips here. Thank you!

Answer 1

Spring Boot is based on Singleton model if you didn't specify the bean scope which means every component that you specify as bean (@Component, @Service or whatever-else) when you @Autowired that component no matter anywhere, it will always be that same instance and that is why your state is not reset.

Hope this help answer your question.