Mapping MultipartFile with userId

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In this article, we will explore how to map a MultipartFile object with the userId of the logged-in user. We’ll dive into the technical details of handling file uploads and user authentication in a Spring-based application.

The Problem

The problem arises when trying to upload an Excel file containing product data. The Product entity is mapped to the user_id column, but the uploaded file doesn’t contain any user information. As a result, we get an error stating that NULL values are not allowed for the USER_ID column.

Solution Overview

To solve this issue, we need to map the uploaded MultipartFile object with the userId of the logged-in user. We’ll use Spring Security’s SecurityContextHolder and the @Autowired annotation to inject the necessary dependencies.

Step 1: User Authentication

First, let’s ensure that the user is authenticated before attempting to upload the file. We can do this by using the SecurityContextHolder.getContext().getAuthentication() method to retrieve the authentication context.

User user = (User) SecurityContextHolder.getContext().getAuthentication().getPrincipal();

This will give us access to the currently logged-in user’s information, including their ID.

Step 2: Mapping MultipartFile with userId

Next, we need to map the uploaded MultipartFile object with the userId. We can do this by using the @RequestParam annotation on our controller method to inject the file as a parameter.

@PostMapping("/api/excel/upload/")
public ResponseEntity<ResponseMessage> uploadFile(@RequestParam("file") MultipartFile file){
    String message = "";
    if (ExcelHelper.hasExcelFormat(file)){
        try{
            // Map the uploaded file with the userId
            String userId = user.getId().toString();
            excelService.save(userId, file);
            message = "upload succeeded: " + file.getOriginalFilename();
            return ResponseEntity.status(HttpStatus.OK).body(new ResponseMessage(message));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    message = "please upload file";
    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(new ResponseMessage(message));
}

In this example, we’re mapping the uploaded MultipartFile object with the userId by injecting it as a parameter into our controller method. We can then use the user.getId() method to retrieve the user’s ID and map it with the file.

Step 3: Updating Product Entity

Finally, we need to update the Product entity to include the mapped userId. We can do this by using the @JoinColumn annotation on our Product entity.

@EntityScan
@Entity
@ApiModel
public class Product extends BaseEntity {
    @Id
    @GeneratedValue
    @Column(name = "product_id")
    private Long id;

    @JsonIgnore
    @ManyToOne(fetch = FetchType.LAZY,optional = false)
    @JoinColumn(name = "user_id")
    private User user;
}

In this example, we’re updating the Product entity to include a @JoinColumn annotation on the user_id column. This will allow us to map the uploaded file with the userId.

Step 4: Handling Excel Upload

Now that we’ve mapped the uploaded file with the userId, we can handle the Excel upload process by using our ExcelService class.

@Service
public class ExcelService {
    @Autowired
    ProductRepository repository;

    public void save(String userId, MultipartFile file){
        try{
            List<Product> excelEntities = ExcelHelper.excelToExcelEntity(file.getInputStream());
            // Update the Product entity with the mapped userId
            for (Product product : excelEntities) {
                product.setUser(userId);
            }
            repository.saveAll(excelEntities);
        } catch (IOException e){
            throw new RuntimeException("failed" + e.getMessage());
        }
    }
}

In this example, we’re handling the Excel upload process by using our ExcelService class. We’re mapping the uploaded file with the userId and updating the Product entity accordingly.

Conclusion

Mapping a MultipartFile object with the userId requires careful consideration of user authentication and data mapping. By following these steps, we can ensure that the uploaded file is properly mapped with the user’s ID and updated in our database.

Last modified on 2024-07-04