Angular 6 – Upload/Get MultipartFile to/from Spring Boot Server

When uploading files to Servlet containers, application needs to register a MultipartConfigElement class. But Spring Boot makes thing more easy by configuring it automatically. In this tutorial, we’re gonna look at way to build an Angular 6 App Client to upload/get MultipartFile to/from Spring Boot RestApi Server.

Related posts:
How to upload MultipartFile with Spring Boot
MultipartFile – SpringBoot + JQuery Ajax + Bootstrap.
MultipartFile – SpringBoot + AngularJs + Bootstrap.

I. Technologies

– Angular 6
– Java 1.8
– Spring Boot 2.0.3.RELEASE
– Maven 3.3.9
– Spring Tool Suite 3.9.0.RELEASE

II. Overview

1. Spring Boot Server

angular-6-upload-multipart-files-spring-boot-server-project-structure-server

StorageService helps to init, delete all files, store file, load file
UploadController uses StorageService to provide Rest API: POST a file, GET all files
application.properties to configure parameters such as MultipartFile max size…
– Spring Boot Starter Web dependency in pom.xml

2. Angular 6 App Client

angular-6-upload-multipart-files-spring-boot-server-project-structure-client

upload-file.service provides methods: push File to Storage and get Files.
list-upload.component gets and displays list of Files.
form-upload.component helps upload File.
details-upload.component is detail for each item in list of Files.

angular-6-upload-multipart-file-spring-boot-angular-overview

III. Practice

1. Spring Boot Server

1.1 Create Spring Boot project

With Dependency:

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-web</artifactId>
</dependency>

1.2 Create Storage Service for File Systems

Create StorageService with 4 functions:
– public void store(MultipartFile file): save a file
– public Resource loadFile(String filename): load a file
– public void deleteAll(): remove all uploaded files
– public void init(): create upload directory

storage/StorageService.java


package com.javasampleapproach.spring.uploadfiles.storage;

import java.io.IOException;
import java.net.MalformedURLException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.io.Resource;
import org.springframework.core.io.UrlResource;
import org.springframework.stereotype.Service;
import org.springframework.util.FileSystemUtils;
import org.springframework.web.multipart.MultipartFile;

@Service
public class StorageService {

	Logger log = LoggerFactory.getLogger(this.getClass().getName());
	private final Path rootLocation = Paths.get("upload-dir");

	public void store(MultipartFile file) {
		try {
			Files.copy(file.getInputStream(), this.rootLocation.resolve(file.getOriginalFilename()));
		} catch (Exception e) {
			throw new RuntimeException("FAIL!");
		}
	}

	public Resource loadFile(String filename) {
		try {
			Path file = rootLocation.resolve(filename);
			Resource resource = new UrlResource(file.toUri());
			if (resource.exists() || resource.isReadable()) {
				return resource;
			} else {
				throw new RuntimeException("FAIL!");
			}
		} catch (MalformedURLException e) {
			throw new RuntimeException("FAIL!");
		}
	}

	public void deleteAll() {
		FileSystemUtils.deleteRecursively(rootLocation.toFile());
	}

	public void init() {
		try {
			Files.createDirectory(rootLocation);
		} catch (IOException e) {
			throw new RuntimeException("Could not initialize storage!");
		}
	}
}

1.3 Create Upload Controller

controller/UploadController.java


package com.javasampleapproach.spring.uploadfiles.controller;

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.mvc.method.annotation.MvcUriComponentsBuilder;

import com.javasampleapproach.spring.uploadfiles.storage.StorageService;

@Controller
public class UploadController {

	@Autowired
	StorageService storageService;

	List files = new ArrayList();

	@PostMapping("/post")
	public ResponseEntity handleFileUpload(@RequestParam("file") MultipartFile file) {
		String message = "";
		try {
			storageService.store(file);
			files.add(file.getOriginalFilename());

			message = "You successfully uploaded " + file.getOriginalFilename() + "!";
			return ResponseEntity.status(HttpStatus.OK).body(message);
		} catch (Exception e) {
			message = "FAIL to upload " + file.getOriginalFilename() + "!";
			return ResponseEntity.status(HttpStatus.EXPECTATION_FAILED).body(message);
		}
	}

	@GetMapping("/getallfiles")
	public ResponseEntity> getListFiles(Model model) {
		List fileNames = files
				.stream().map(fileName -> MvcUriComponentsBuilder
						.fromMethodName(UploadController.class, "getFile", fileName).build().toString())
				.collect(Collectors.toList());

		return ResponseEntity.ok().body(fileNames);
	}

	@GetMapping("/files/{filename:.+}")
	@ResponseBody
	public ResponseEntity getFile(@PathVariable String filename) {
		Resource file = storageService.loadFile(filename);
		return ResponseEntity.ok()
				.header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + file.getFilename() + "\"")
				.body(file);
	}
}

1.4 Config multipart

Open application.properties:


spring.servlet.multipart.max-file-size=500KB
spring.servlet.multipart.max-request-size=500KB

spring.servlet.multipart.max-file-size: limit total file size for each request.
spring.servlet.multipart.max-request-size: limit total request size for a multipart/form-data.

1.5 Init Storage for File System

SpringBootUploadFileApplication.java


package com.javasampleapproach.spring.uploadfiles;

import javax.annotation.Resource;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import com.javasampleapproach.spring.uploadfiles.storage.StorageService;

@SpringBootApplication
public class SpringBootFileUploadApplication implements CommandLineRunner {

	@Resource
	StorageService storageService;

	public static void main(String[] args) {
		SpringApplication.run(SpringBootFileUploadApplication.class, args);
	}

	@Override
	public void run(String... arg) throws Exception {
		storageService.deleteAll();
		storageService.init();
	}
}

2. Angular 6 App Client

2.0 Generate Service & Components

Run commands below:
ng g s upload/UploadFile
ng g c upload/FormUpload
ng g c upload/ListUpload
ng g c upload/DetailsUpload
On each Component selector, delete app- prefix, then change tslint.json rules"component-selector" to false.

2.1 App Module

app.module.ts


import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { HttpClientModule } from '@angular/common/http';

import { AppComponent } from './app.component';
import { DetailsUploadComponent } from './upload/details-upload/details-upload.component';
import { FormUploadComponent } from './upload/form-upload/form-upload.component';
import { ListUploadComponent } from './upload/list-upload/list-upload.component';

@NgModule({
  declarations: [
    AppComponent,
    DetailsUploadComponent,
    FormUploadComponent,
    ListUploadComponent
  ],
  imports: [
    BrowserModule,
    HttpClientModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

2.2 Upload File Service

upload/upload-file.service.ts


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

@Injectable({
  providedIn: 'root'
})
export class UploadFileService {

  constructor(private http: HttpClient) { }

  pushFileToStorage(file: File): Observable> {
    const formdata: FormData = new FormData();

    formdata.append('file', file);

    const req = new HttpRequest('POST', '/post', formdata, {
      reportProgress: true,
      responseType: 'text'
    });

    return this.http.request(req);
  }

  getFiles(): Observable {
    return this.http.get('/getallfiles');
  }
}

2.3 Component for getting List of Files

upload/list-upload.component.ts


import { Component, OnInit } from '@angular/core';
import { Observable } from 'rxjs';
import { UploadFileService } from '../upload-file.service';

@Component({
  selector: 'list-upload',
  templateUrl: './list-upload.component.html',
  styleUrls: ['./list-upload.component.css']
})
export class ListUploadComponent implements OnInit {

  showFile = false;
  fileUploads: Observable;

  constructor(private uploadService: UploadFileService) { }

  ngOnInit() {
  }

  showFiles(enable: boolean) {
    this.showFile = enable;

    if (enable) {
      this.fileUploads = this.uploadService.getFiles();
    }
  }
}

upload/list-upload.component.html

<button class="button btn-info" *ngIf='showFile' (click)='showFiles(false)'>Hide Files</button>

<button class="button btn-info" *ngIf='!showFile' (click)='showFiles(true)'>Show Files</button>

<div [hidden]="!showFile">
  <div class="panel panel-primary">
    <div class="panel-heading">List of Files</div>
    <div *ngFor="let file of fileUploads | async">
      <div class="panel-body">
        <details-upload [fileUpload]='file'></details-upload>
      </div>
    </div>
  </div>
</div>

upload/details-upload.component.ts


import { Component, OnInit, Input } from '@angular/core';

@Component({
  selector: 'details-upload',
  templateUrl: './details-upload.component.html',
  styleUrls: ['./details-upload.component.css']
})
export class DetailsUploadComponent implements OnInit {

  @Input() fileUpload: string;

  constructor() { }

  ngOnInit() {
  }

}

upload/details-upload.component.html

<a href="{{fileUpload}}">{{fileUpload}}</a>

2.4 Component for uploading File

upload/form-upload.component.ts


import { Component, OnInit } from '@angular/core';
import { UploadFileService } from '../upload-file.service';
import { HttpResponse, HttpEventType } from '@angular/common/http';

@Component({
  selector: 'form-upload',
  templateUrl: './form-upload.component.html',
  styleUrls: ['./form-upload.component.css']
})
export class FormUploadComponent implements OnInit {

  selectedFiles: FileList;
  currentFileUpload: File;
  progress: { percentage: number } = { percentage: 0 };

  constructor(private uploadService: UploadFileService) { }

  ngOnInit() {
  }

  selectFile(event) {
    this.selectedFiles = event.target.files;
  }

  upload() {
    this.progress.percentage = 0;

    this.currentFileUpload = this.selectedFiles.item(0);
    this.uploadService.pushFileToStorage(this.currentFileUpload).subscribe(event => {
      if (event.type === HttpEventType.UploadProgress) {
        this.progress.percentage = Math.round(100 * event.loaded / event.total);
      } else if (event instanceof HttpResponse) {
        console.log('File is completely uploaded!');
      }
    });

    this.selectedFiles = undefined;
  }

}

upload/form-upload.component.html

<div *ngIf="currentFileUpload" class="progress">
  <div class="progress-bar progress-bar-info progress-bar-striped" role="progressbar" attr.aria-valuenow="{{progress.percentage}}"
    aria-valuemin="0" aria-valuemax="100" [ngStyle]="{width:progress.percentage+'%'}">
    {{progress.percentage}}%</div>
</div>

<label class="btn btn-default">
  <input type="file" (change)="selectFile($event)">
</label>

<button class="btn btn-success" [disabled]="!selectedFiles" (click)="upload()">Upload</button>

2.5 App Component

app.component.ts


import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'JavaSampleApproach';
  description = 'Angular-SpringBoot Demo';
}

app.component.html

<div class="container" style="width:400px">
  <div style="color: blue; margin-bottom: 20px">
    <h1>{{title}}</h1>
    <h3>{{description}}</h3>
  </div>

  <form-upload></form-upload>

  <br/>
  <br/>

  <list-upload></list-upload>
</div>

2.6 Integrate Spring Boot Server with Angular 6 client

– Create proxy.conf.json file under project:


{
	"/": {
		"target": "http://localhost:8080",
		"secure": false
	}
}

– Edit package.json file for ‘start’ script:


...
  "scripts": {
    "ng": "ng",
    "start": "ng serve --proxy-config proxy.conf.json",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
...

3. Check Results

Run Spring Boot Server and Angular 6 Client App (npm start).
Open Browser with url http://localhost:4200/.

Upload files and show list of Files:

angular-6-upload-multipart-files-spring-boot-server-browser-result

Inside Spring Project folder, open upload-dir folder:

angular-6-upload-multipart-files-spring-boot-server-folder-result

IV. Sourcecode

SpringBootFileUpload-Server
Angular6Upload-Client



By grokonez | June 27, 2018.

Last updated on March 12, 2021.



Related Posts


9 thoughts on “Angular 6 – Upload/Get MultipartFile to/from Spring Boot Server”

    1. for me, it helped to start the frontend over npm run start, because it takes automatically the proxy.conf.json file. otherwise you have to define it over ng serve..

  1. I used a majority of the shown code and it works well with Angular 6 and Java 8.
    Thank you very much for taking the time to write this tutorial.

  2. Hi,

    Thanks for the great blog and well described. I am getting an below error when I upload the file into spring boot.
    Could you please help on this one.
    Failed to load resource: the server responded with a status of 404 (Not Found) [http://localhost:4200/post]
    null: ERROR
    null: HttpErrorResponse {headers: HttpHeaders, status: 404, statusText: “Not Found”, url: “http://localhost:4200/post”, ok: false, …}

  3. hi ! good project , you know how do to, reload list of files when we add file and upload file show 100% ?
    I want do without click show/hide file all the time

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