How would I implement a spring contractor to send blob data to mySql database

Here is my Post class Entity.

The aim is to send images to the database through an API endpoint that I will youse in my website.

@Entity(name = "posts")
public class Post {

  @Id
  @Column(name = "Id", nullable = false)
  private String id;

  @Column(name = "Post_title", nullable = false)
  private String title;

  @Column(name = "creator", nullable = false)
  private String creator;

  @Lob
  @Column(name = "post_image", nullable = false)
  private Byte[] postImage;

  @Column(name = "descriptions", nullable = false)
  private String descriptions;

  public String getId() {
    return id;
  }

  public void setId(String id) {
    this.id = id;
  }

  public String getTitle() {
    return title;
  }

  public void setTitle(String title) {
    this.title = title;
  }

  public String getCreator() {
    return creator;
  }

  public void setCreator(String creator) {
    this.creator = creator;
  }

  public Byte[] getPostImage() {
    return postImage;
  }

  public void setPostImage(Byte[] postImage) {
    this.postImage = postImage;
  }

  public String getDescriptions() {
    return descriptions;
  }

  public void setDescriptions(String descriptions) {
    this.descriptions = descriptions;
  }
}

This is the java spring controller for the api
The plan is to convert the image with javaScript, I want to have less java code

@RestController
@RequestMapping("/api/posts")
public class PostController {

    @Autowired
    private PostRepository postRepository;

    @PostMapping
    public ResponseEntity<Post> createPost(@RequestBody Post post) {
        Post newPost = postRepository.save(post);
        return new ResponseEntity<>(newPost, HttpStatus.CREATED);
    }
}

here is how I implemented the convention of images into a byte

const inputElement = document.getElementById("image-input");

inputElement.addEventListener("change", function() {
  const file = inputElement.files[0];
  const reader = new FileReader();
  reader.readAsBinaryString(file);
  reader.onload = function() {
    const blob = new Blob([reader.result], { type: file.type });
    const byteArray = new Uint8Array(blob);
    // Now you can send the byteArray to your API endpoint
  };
});