Spring Boot Rest Api for File Upload

In this tutorial, I will testify you how to upload and download files with a Spring Boot Rest APIs to/from a static binder. We also apply Jump Web MultipartFile interface to handle HTTP multi-function requests.

This Spring Boot App works with:
– Angular 8 Client / Angular 10 Customer / Angular xi Client / Angular 12
– Angular Material 12
– Vue Customer / Vuetify Client
– React Client / React Hooks Client
– Material UI Customer
– React Image Upload with Preview
– Axios Client

Related Posts:
– How to upload multiple files in Java Bound Boot
– Spring Boot: Upload/Import Excel file data into MySQL Database
– Spring Boot: Upload/Import CSV file data into MySQL Database

Deployment: Deploy Jump Boot App on AWS – Rubberband Beanstalk

Leap Boot Residuum APIs for uploading Files

Our Jump Kick Application will provide APIs for:

• uploading File to a static binder in the Server
• downloading File from server with the link
• getting listing of Files' information (file name & url)

These are APIs to be exported:

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

This is the static folder that stores all uploaded files:

If you lot want to store files in database like this:

Yous can discover pedagogy at:
Spring Boot Upload/Download File to/from Database example

Technology

• Java 8
• Bound Boot 2 (with Spring Spider web MVC)
• Maven three.6.1

Project Structure

Let me explain information technology briefly.

– FileInfo contains information of the uploaded file.
– FilesStorageService helps us to initialize storage, save new file, load file, become list of Files' info, delete all files.
– FilesController uses FilesStorageService to export Residuum APIs: POST a file, GET all files' information, download a File.
– FileUploadExceptionAdvice handles exception when the controller processes file upload.
– application.backdrop contains configuration for Servlet Multipart.
– uploads is the static folder for storing files.
– pom.xml for Bound Kick dependency.

Setup Spring Boot project

Use Jump spider web tool or your development tool (Spring Tool Suite, Eclipse, Intellij) to create a Jump Boot project.

Then open pom.xml and add together these dependencies:

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

Create Service for File Storage

First we need an interface that volition be autowired in the Controller.
In service folder, create FilesStorageService interface similar post-obit code:

service/FilesStorageService.coffee

          packet com.bezkoder.spring.files.upload.service; import coffee.nio.file.Path; import coffee.util.stream.Stream; import org.springframework.core.io.Resource; import org.springframework.spider web.multipart.MultipartFile; public interface FilesStorageService {   public void init();   public void salvage(MultipartFile file);   public Resource load(Cord filename);   public void deleteAll();   public Stream<Path> loadAll(); }                  

Now nosotros create implementation of the interface.

service/FilesStorageServiceImpl.java

          packet com.bezkoder.spring.files.upload.service; import java.io.IOException; import java.net.MalformedURLException; import java.nio.file.Files; import java.nio.file.Path; import coffee.nio.file.Paths; import java.util.stream.Stream; 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 FilesStorageServiceImpl implements FilesStorageService {   private final Path root = Paths.get("uploads");   @Override   public void init() {     try {       Files.createDirectory(root);     } catch (IOException e) {       throw new RuntimeException("Could not initialize folder for upload!");     }   }   @Override   public void relieve(MultipartFile file) {     endeavour {       Files.copy(file.getInputStream(), this.root.resolve(file.getOriginalFilename()));     } catch (Exception east) {       throw new RuntimeException("Could not store the file. Error: " + e.getMessage());     }   }   @Override   public Resource load(String filename) {     try {       Path file = root.resolve(filename);       Resources resource = new UrlResource(file.toUri());       if (resource.exists() || resource.isReadable()) {         return resource;       } else {         throw new RuntimeException("Could not read the file!");       }     } take hold of (MalformedURLException due east) {       throw new RuntimeException("Error: " + e.getMessage());     }   }   @Override   public void deleteAll() {     FileSystemUtils.deleteRecursively(root.toFile());   }   @Override   public Stream<Path> loadAll() {     try {       return Files.walk(this.root, ane).filter(path -> !path.equals(this.root)).map(this.root::relativize);     } catch (IOException e) {       throw new RuntimeException("Could not load the files!");     }   } }                  

Define Data Models

Permit's create FileInfo model which has fields: name & url.

model/FileInfo.java

          bundle com.bezkoder.spring.files.upload.model; public form FileInfo {   private String name;   private Cord url;   public FileInfo(Cord name, String url) {     this.name = name;     this.url = url;   }   public String getName() {     return this.name;   }   public void setName(Cord proper noun) {     this.name = name;   }   public String getUrl() {     return this.url;   }   public void setUrl(String url) {     this.url = url;   } }                  

Define Response Message

The ResponseMessage is for message to client that we're gonna utilise in Rest Controller and Exception Handler.

message/ResponseMessage.java

          packet com.bezkoder.jump.files.upload.bulletin; public class ResponseMessage {   private String message;   public ResponseMessage(String message) {     this.message = message;   }   public String getMessage() {     return message;   }   public void setMessage(Cord message) {     this.message = message;   } }                  

Create Controller for upload & download Files

In controller package, we create FilesController.

controller/FilesController.java

          package com.bezkoder.jump.files.upload.controller; import java.util.Listing; import java.util.stream.Collectors; import org.springframework.beans.mill.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.spider web.bind.annotation.CrossOrigin; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.note.PathVariable; import org.springframework.web.demark.note.PostMapping; import org.springframework.spider web.bind.note.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.bezkoder.bound.files.upload.model.FileInfo; import com.bezkoder.spring.files.upload.model.ResponseMessage; import com.bezkoder.leap.files.upload.service.FilesStorageService; @Controller @CrossOrigin("http://localhost:8081") public class FilesController {   @Autowired   FilesStorageService storageService;   @PostMapping("/upload")   public ResponseEntity<ResponseMessage> uploadFile(@RequestParam("file") MultipartFile file) {     String message = "";     try {       storageService.save(file);       message = "Uploaded the file successfully: " + file.getOriginalFilename();       return ResponseEntity.status(HttpStatus.OK).torso(new ResponseMessage(message));     } take hold of (Exception e) {       message = "Could not upload the file: " + file.getOriginalFilename() + "!";       render ResponseEntity.status(HttpStatus.EXPECTATION_FAILED).torso(new ResponseMessage(message));     }   }   @GetMapping("/files")   public ResponseEntity<List<FileInfo>> getListFiles() {     List<FileInfo> fileInfos = storageService.loadAll().map(path -> {       String filename = path.getFileName().toString();       Cord url = MvcUriComponentsBuilder           .fromMethodName(FilesController.form, "getFile", path.getFileName().toString()).build().toString();       render new FileInfo(filename, url);     }).collect(Collectors.toList());     render ResponseEntity.status(HttpStatus.OK).body(fileInfos);   }   @GetMapping("/files/{filename:.+}")   @ResponseBody   public ResponseEntity<Resources> getFile(@PathVariable String filename) {     Resource file = storageService.load(filename);     return ResponseEntity.ok()         .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + file.getFilename() + "\"").body(file);   } }                  

– @CrossOrigin is for configuring immune origins.
– @Controller notation is used to define a controller.
– @GetMapping and @PostMapping annotation is for mapping HTTP Go & Post requests onto specific handler methods:

• Mail /upload: uploadFile()
• Go /files: getListFiles()
• Become /files/[filename]: getFile()

– We use @Autowired to inject implementation of FilesStorageService bean to local variable.

Configure Multipart File for Servlet

Allow'southward define the maximum file size that can be uploaded in application.properties as following:

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

– jump.servlet.multipart.max-file-size: max file size for each request.
– leap.servlet.multipart.max-asking-size: max request size for a multipart/form-data.

Handle File Upload Exception

This is where we handle the case in that a request exceeds Max Upload Size. The arrangement volition throw MaxUploadSizeExceededException and we're gonna utilise @ControllerAdvice with @ExceptionHandlerannotation for handling the exceptions.

exception/FileUploadExceptionAdvice.java

          package com.bezkoder.spring.files.upload.exception; import org.springframework.web.multipart.MaxUploadSizeExceededException; import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler; import com.bezkoder.jump.files.upload.model.ResponseMessage; import org.springframework.http.HttpStatus; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.ControllerAdvice; import org.springframework.spider web.bind.notation.ExceptionHandler; @ControllerAdvice public class FileUploadExceptionAdvice extends ResponseEntityExceptionHandler {   @ExceptionHandler(MaxUploadSizeExceededException.form)   public ResponseEntity<ResponseMessage> handleMaxSizeException(MaxUploadSizeExceededException exc) {     render ResponseEntity.status(HttpStatus.EXPECTATION_FAILED).body(new ResponseMessage("File too large!"));   } }                  

Initialize Storage

We demand to run init() method of FilesStorageService (and also deleteAll() if necessary). So open SpringBootUploadFilesApplication.java and implement CommandLineRunner for run() method like this:

          package com.bezkoder.spring.files.upload; import javax.annotation.Resource; import org.springframework.kicking.CommandLineRunner; import org.springframework.kick.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import com.bezkoder.spring.files.upload.service.FilesStorageService; @SpringBootApplication public class SpringBootUploadFilesApplication implements CommandLineRunner {   @Resource   FilesStorageService storageService;   public static void master(String[] args) {     SpringApplication.run(SpringBootUploadFilesApplication.form, args);   }   @Override   public void run(String... arg) throws Exception {     storageService.deleteAll();     storageService.init();   } }                  

Run & Examination

Run Spring Boot awarding with command: mvn leap-boot:run.
Refresh the project directory and you lot will see uploads folder within it.

Allow's use Postman to make some requests.

– Upload some files:

– Upload a file with size larger than max file size (500KB):

– Check uploads folder:

– Retrieve list of Files' information:

– Now yous tin can download any file from one of the paths to a higher place.
For example: http://localhost:8080/files/bezkoder.png.

Conclusion

Today nosotros've learned how to create Spring Boot File Upload Rest Api Application to upload multipart files and go files' information with static folder via Restful API.

Following tutorials explain how to build Front-end Apps to work with our Spring Kicking Server:
– Angular 8 Client / Angular x Client / Angular eleven Customer / Athwart 12
– Angular Textile 12
– Vue Client / Vuetify Customer
– React Client / React Hooks Client
– Material UI Client
– React Paradigm Upload with Preview
– Axios Customer

For multiple Files at in one case:
How to upload multiple files in Java Jump Boot

Y'all can also know way to upload an Excel/CSV file and store the content in MySQL database with the post:
– Spring Boot: Upload/Import Excel file data into MySQL Database
– Bound Boot: Upload/Import CSV file data into MySQL Database

If you want to store files in database similar this:

Y'all can find instruction at:
Bound Boot Upload/Download File to/from Database case

Happy Learning! See you once more.

Further Reading

• Multipart Content-Type

Source Code

Y'all can find the complete source code for this tutorial on Github.

applegatelivalwas.blogspot.com

Source: https://www.bezkoder.com/spring-boot-file-upload/

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