Angular 17 + Spring Boot: File upload/download example

In this tutorial, I will show you way to build Angular 17 File upload & download example with Spring Boot Rest API server.

More Practice:
Spring Boot + Thymeleaf: File Upload example
Angular 17 + Spring Boot: CRUD example
Angular 17 + Spring Boot: JWT Authentication example
Angular + Spring Boot: Pagination example

For Image/Multiple Files Upload at once:
Angular 17 Image Upload with Preview example
Angular 17 Multiple Files upload example

Serverless with Firebase:
Angular 17 File Upload with Firebase Storage

With Angular Material:
Angular Material 17 File upload example


Overview

We’re gonna create a full-stack Angular 17 + Spring Boot File upload/download example in which user can:

  • know the file upload status
  • view all uploaded files
  • download by clicking on the file name

angular-17-spring-boot-file-upload-download-example

All uploaded files will be saved in uploads folder:

angular-17-spring-boot-file-upload-folder-example

You can change Spring Boot server for uploading file to database:
Spring Boot File upload to database example

Angular Client with Progress Bar (working with this Spring Server):
Angular 17 File upload example with Progress bar

If you want to upload image with preview, you can visit:
Angular 17 Image Upload with Preview example

Angular 17 + Spring Boot File upload Architecture

Let’s look at the architecture below:

angular-17-spring-boot-file-upload-download-example-architecture

Angular 17 Client:

  • FileUpload Component calls UploadService functions for upload/download/display files
  • UploadService uses HttpClientModule to make HTTP requests

Spring Boot Server:

  • FilesController receives the HTTP requests from Client, then calls FilesStorageService functions for upload/download/getting files
  • FilesStorageService implements functions for storing and retrieving file systems using Java Files library

Technology

Server:

  • Java 17 / 11 / 8
  • Spring Boot 3 / 2 (with Spring Web MVC)
  • Maven

Client:

  • Angular 17
  • RxJS 7
  • Bootstrap 4

Spring Boot Rest APIs for File Upload & Storage

Spring Boot App will provide APIs:

Methods Urls Actions
POST /upload upload a File
GET /files get List of Files (name & url)
GET /files/[filename] download a File

This is the project structure:

angular-17-spring-boot-file-upload-download-example-project-structure

FileInfo contains information of the uploaded file.
FilesStorageService helps us to initialize storage, save new file, load file, get list of Files’ info, delete all files.
FilesController uses FilesStorageService to export Rest APIs: POST a file, GET all files’ information, download a File.
FileUploadExceptionAdvice handles exception when the controller processes file upload.
application.properties contains configuration for Servlet Multipart.
pom.xml for Spring Boot dependency.

You can find Step by Step to implement the Spring Boot Server (with Github) at:
Spring Boot Multipart File upload (to static folder) example

Or: Spring Boot Multipart File upload (to database) example

Angular 17 Client for file upload/download UI

Let’s open cmd and use Angular CLI to create a new Angular 17 Project as following command:

ng new angular-17-file-upload
? Which stylesheet format would you like to use? CSS
? Do you want to enable Server-Side Rendering (SSR) and Static Site Generation (SSG/Prerendering)? No

We also need to generate some Components and Services:

ng g s services/file-upload
ng g c components/file-upload

Now you can see that our project directory structure looks like this.

Angular 17 Project Structure

angular-17-spring-boot-file-upload-download-example-client-project

Let me explain it briefly.

– We import necessary library in app.config.ts.
file-upload.service provides methods to save File and get Files from Rest API Server using HttpClient.
file-upload.component contains upload form, display of list files.
app.component is the container that we embed all components.
angular.json for importing the Bootstrap library.

Set up HttpClient

Open app.config.ts and import provideHttpClient from Angular Http Module:

import { ApplicationConfig } from '@angular/core';
import { provideRouter } from '@angular/router';
import { provideHttpClient } from '@angular/common/http';

import { routes } from './app.routes';

export const appConfig: ApplicationConfig = {
  providers: [
    provideRouter(routes),
    provideHttpClient()
  ]
};

Add Bootstrap to the project

Run the command: npm install [email protected].

Next, open angular.json and add following code:

"styles": [
  "node_modules/bootstrap/dist/css/bootstrap.min.css",
  "src/styles.css"
],
"scripts": [
  "node_modules/jquery/dist/jquery.slim.min.js",
  "node_modules/popper.js/dist/umd/popper.min.js",
  "node_modules/bootstrap/dist/js/bootstrap.min.js"
]

Create Angular 17 Service for Upload Files to Spring Boot Server

This service will use Angular HttpClient to send HTTP requests.
There are 2 functions:

  • upload(file): returns Observable<HttpEvent<any>> that we’re gonna use in File Upload Component
  • getFiles(): returns a list of Files’ information as Observable object

services/file-upload.service.ts

import { Injectable } from '@angular/core';
import { HttpClient, HttpRequest, HttpEvent } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root',
})
export class FileUploadService {
  private baseUrl = 'http://localhost:8080';

  constructor(private http: HttpClient) {}

  upload(file: File): Observable<HttpEvent<any>> {
    const formData: FormData = new FormData();
    formData.append('file', file);

    const req = new HttpRequest('POST', `${this.baseUrl}/upload`, formData, {
      responseType: 'json',
    });

    return this.http.request(req);
  }

  getFiles(): Observable<any> {
    return this.http.get(`${this.baseUrl}/files`);
  }
}

FormData is a data structure that can be used to store key-value pairs. We use it to build an object which corresponds to an HTML form with append() method.
– We call the request(PostRequest) & get() method of HttpClient to send an HTTP POST & Get request to the File Upload Rest API server.

Create Component for File Upload UI

Let’s create a File Upload UI with Card, Button and Message.

First we need to use the following imports:

file-upload.component.ts

import { Component, OnInit } from '@angular/core';
import { CommonModule } from '@angular/common';
import { HttpResponse } from '@angular/common/http';
import { Observable } from 'rxjs';
import { FileUploadService } from '../../services/file-upload.service';

@Component({
  selector: 'app-file-upload',
  standalone: true,
  imports: [CommonModule],
  templateUrl: './file-upload.component.html',
  styleUrl: './file-upload.component.css',
})
export class FileUploadComponent implements OnInit { ... }

Then we define the some variables and inject FileUploadService as follows:

export class FileUploadComponent implements OnInit {
  currentFile?: File;
  message = '';
  fileInfos?: Observable<any>;

  constructor(private uploadService: FileUploadService) { }

}

Next we define selectFile() method. It helps us to get the selected File.

selectFile(event: any): void {
  this.currentFile = event.target.files.item(0);
}

Next we write upload() method for upload file:

export class FileUploadComponent implements OnInit {
  currentFile?: File;
  message = '';
  fileInfos?: Observable<any>;

  constructor(private uploadService: FileUploadService) { }

  selectFile(event: any): void {
    this.currentFile = event.target.files.item(0);
  }

  upload(): void {
    if (this.currentFile) {
      this.uploadService.upload(this.currentFile).subscribe({
        next: (event: any) => {
          if (event instanceof HttpResponse) {
            this.message = event.body.message;
            this.fileInfos = this.uploadService.getFiles();
          }
        },
        error: (err: any) => {
          console.log(err);

          if (err.error && err.error.message) {
            this.message = err.error.message;
          } else {
            this.message = 'Could not upload the file!';
          }
        },
        complete: () => {
          this.currentFile = undefined;
        },
      });
    }
  }
}

We use currentFile for accessing current File as the first Item. Then we call uploadService.upload() method on the currentFile.

If the transmission is done, the event will be a HttpResponse object. At this time, we call uploadService.getFiles() to get the files’ information and assign the result to fileInfos variable.

We also need to do this work in ngOnInit() method:

ngOnInit(): void {
  this.fileInfos = this.uploadService.getFiles();
}

Now we create the HTML template of the Upload File UI. Add the following content to file-upload.component.html file:

<div class="row">
  <div class="col-8">
    <label class="btn btn-default p-0">
      <input type="file" (change)="selectFile($event)" />
    </label>
  </div>

  <div class="col-4">
    <button class="btn btn-success btn-sm" [disabled]="!currentFile" (click)="upload()">
      Upload
    </button>
  </div>
</div>

@if (message) {
<div class="alert alert-secondary" role="alert">{{ message }}</div>
}

<div class="card mt-3">
  <div class="card-header">List of Files</div>
  <ul class="list-group list-group-flush">
    @for (file of fileInfos | async; track file.name) {
    <li class="list-group-item">
      <a href="{{ file.url }}">{{ file.name }}</a>
    </li>
    }
  </ul>
</div>

Add Upload File Component to App Component

Import FileUploadComponent in app.component.ts

import { Component } from '@angular/core';
import { CommonModule } from '@angular/common';
import { RouterOutlet } from '@angular/router';
import { FileUploadComponent } from './components/file-upload/file-upload.component';

@Component({
  selector: 'app-root',
  standalone: true,
  imports: [CommonModule, RouterOutlet, FileUploadComponent],
  templateUrl: './app.component.html',
  styleUrl: './app.component.css'
})
export class AppComponent {
  title = 'Angular 17 File Upload example';
}

Open app.component.html and embed the FileUpload Component with <app-file-upload> tag.

<div class="container" style="width:500px">
  <div class="my-3">
    <h3>bezkoder.com</h3>
    <h4>{{ title }}</h4>
  </div>

  <app-file-upload></app-file-upload>
</div>

Run the Application

Run Spring Boot Server with command: mvn spring-boot:run.
Refresh the project directory and you will see uploads folder inside it.

Because we configure CORS for origin: http://localhost:8081, so you need to run Angular 17 Client with command:
ng serve --port 8081

Open Browser with url http://localhost:8081/ and check the result.

Further Reading

Using Template Engine:
Thymeleaf + Spring Boot: File Upload example

Fullstack CRUD App:
Angular 17 + Spring Boot + H2 example
Angular 17 + Spring Boot + MySQL example
Angular 17 + Spring Boot + PostgreSQL example
Angular 17 + Spring Boot + MongoDB example

Serverless with Firebase:
Angular 17 File Upload with Firebase Storage

Conclusion

Today we’re learned how to build an example for upload Files from Angular 17 to Spring Boot server. We also provide the ability to show list of files, upload progress using Bootstrap, and to download file from the server.

Next tutorials will show you way to implement the full-stack (with source code):
– Back-end: File Upload to Static folder / File Upload to Database
Front-end / Front-end with Progress Bar

If you want to upload multiple files at once like this:

angular-17-multiple-file-upload-example

You can find the instruction (with Github) here:
Angular 17 Multiple Files upload example

Or use Angular Material like this:

angular-material-17-file-upload-example-progress-bar

Please visit: Angular Material 17 File upload example

You will want to know how to run both projects on same port:
How to Integrate Angular with Spring Boot Rest API

Happy Learning! See you again.