File upload with params in angular

For MultiPart FileUpload spring already provides RequestPart use that.

@RequestParam relies on type conversion via a registered Converter or PropertyEditor while RequestPart relies on HttpMessageConverters taking into consideration the 'Content-Type' header of the request part. RequestParam is likely to be used with name-value form fields.

https://docs.spring.io/spring/docs/current/javadoc- api/org/springframework/web/bind/annotation/RequestPart.html

Use that @RequestPart (value="uploadFile") MultipartFile fichier in Spring Rest Service

 let formData:FormData = new FormData();
    formData.append('uploadFile', file, file.name);
    let headers = new HttpHeaders();
    /** In Angular 5, including the header Content-Type can invalidate your request */
    headers.append('Content-Type', 'multipart/form-data');
    headers.append('Accept', 'application/json');

    let params = new HttpParams();

params.append('level0Name', '1');
params.append('processus', '1');
params.append('nomLibelle', '1');
params.append('anneeFolderName', '1');
params.append('semaineFolderName', '1');
params.append('nomFichier', '1');

    this.httpClient.post(this.resourcePrefix+'/user/upload', formData,  { headers: headers, params: params})

        .subscribe(
            data => console.log('success'),
            error => console.log(error)
        )
}

Try below code.

Angular Service

public uploadFiles(
        nomFichier: string,
        nomLibelle: string,
        processus: string,
        level0Name: string,
        semaineFolderName: string,
        anneeFolderName: string,
        byte: Blob
    ): Observable<any> {

        // headers
        let headers = new HttpHeaders();
        headers.append('Content-Type', 'multipart/form-data');
        let httpRequestHeaders = new HttpRequest({ headers: headers });

        // body data
        let params = new FormData(); 
        params.append('level0Name', level0Name);
        params.append('processus', processus);
        params.append('nomLibelle', nomLibelle);
        params.append('anneeFolderName', anneeFolderName);
        params.append('semaineFolderName', semaineFolderName);
        params.append('nomFichier', nomFichier);
        params.append('fichier', bytes);

        return this.httpClient.post(this.urlUploadFile, params, httpRequestHeaders);
    }

Spring Controller

@PostMapping(path=Urls.UPLOAD_FILE_IN_LIBELLE_GDA, produces = { MediaType.APPLICATION_JSON_VALUE})
    public void uploadFileInLibelleGda(
            @RequestParam String processus,
            @RequestParam String level0Name,
            @RequestParam String nomFichier,
            @RequestParam String nomLibelle,
            @RequestParam String anneeFolderName,
            @RequestParam String semaineFolderName,
            @RequestParam("fichier") MultipartFile fichier) throws Exception {

        uploadService.uploadFileInLibelleGda(racine, processus,level0Name,nomLibelle, anneeFolderName, semaineFolderName, nomFichier,  fichier.getByteArray());
    }