How Can We Throw a Exception Whether Dummy File Uploaded in Java Using Spring With Spring Boot

In this tutorial, I volition evidence you how to upload and download files with a Spring Boot Residuum APIs to/from a static folder. Nosotros as well use Jump Web MultipartFile interface to handle HTTP multi-function requests.

This Leap Kick App works with:
– Angular eight Customer / Athwart 10 Client / Angular 11 Customer / Angular 12
– Angular Cloth 12
– Vue Client / Vuetify Client
– React Client / React Hooks Client
– Textile UI Client
– React Image Upload with Preview
– Axios Client

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

Deployment: Deploy Spring Boot App on AWS – Elastic Beanstalk

Bound Boot Rest APIs for uploading Files

Our Spring Boot Application will provide APIs for:

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

These are APIs to be exported:

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

This is the static binder that stores all uploaded files:

If you want to store files in database like this:

You tin can observe education at:
Leap Boot Upload/Download File to/from Database case

Technology

• Java 8
• Spring Boot 2 (with Spring Web MVC)
• Maven 3.six.one

Project Structure

Allow me explain it briefly.

– 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 consign Rest APIs: Postal service a file, Become all files' information, download a File.
– FileUploadExceptionAdvice handles exception when the controller processes file upload.
– application.properties contains configuration for Servlet Multipart.
– uploads is the static folder for storing files.
– pom.xml for Spring Boot dependency.

Setup Spring Boot project

Utilize Leap web tool or your development tool (Spring Tool Suite, Eclipse, Intellij) to create a Jump Kick project.

And so open up pom.xml and add these dependencies:

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

Create Service for File Storage

Beginning we need an interface that will be autowired in the Controller.
In service folder, create FilesStorageService interface similar following code:

service/FilesStorageService.java

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

At present nosotros create implementation of the interface.

service/FilesStorageServiceImpl.coffee

          package com.bezkoder.bound.files.upload.service; import java.io.IOException; import java.internet.MalformedURLException; import coffee.nio.file.Files; import coffee.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.spider web.multipart.MultipartFile; @Service public class FilesStorageServiceImpl implements FilesStorageService {   private last Path root = Paths.get("uploads");   @Override   public void init() {     effort {       Files.createDirectory(root);     } catch (IOException e) {       throw new RuntimeException("Could not initialize folder for upload!");     }   }   @Override   public void save(MultipartFile file) {     try {       Files.copy(file.getInputStream(), this.root.resolve(file.getOriginalFilename()));     } grab (Exception e) {       throw new RuntimeException("Could non shop the file. Error: " + e.getMessage());     }   }   @Override   public Resources load(String filename) {     attempt {       Path file = root.resolve(filename);       Resources resource = new UrlResource(file.toUri());       if (resource.exists() || resource.isReadable()) {         render resource;       } else {         throw new RuntimeException("Could non read the file!");       }     } take hold of (MalformedURLException e) {       throw new RuntimeException("Fault: " + east.getMessage());     }   }   @Override   public void deleteAll() {     FileSystemUtils.deleteRecursively(root.toFile());   }   @Override   public Stream<Path> loadAll() {     try {       return Files.walk(this.root, 1).filter(path -> !path.equals(this.root)).map(this.root::relativize);     } catch (IOException e) {       throw new RuntimeException("Could non load the files!");     }   } }                  

Define Data Models

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

model/FileInfo.java

          package com.bezkoder.bound.files.upload.model; public class FileInfo {   private Cord name;   private String url;   public FileInfo(String name, String url) {     this.proper name = name;     this.url = url;   }   public Cord getName() {     return this.name;   }   public void setName(Cord name) {     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 nosotros're gonna use in Balance Controller and Exception Handler.

bulletin/ResponseMessage.java

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

Create Controller for upload & download Files

In controller packet, nosotros create FilesController.

controller/FilesController.coffee

          package com.bezkoder.spring.files.upload.controller; import java.util.List; import java.util.stream.Collectors; import org.springframework.beans.factory.note.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.web.bind.notation.CrossOrigin; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.spider web.bind.annotation.RequestParam; import org.springframework.web.bind.notation.ResponseBody; import org.springframework.web.multipart.MultipartFile; import org.springframework.web.servlet.mvc.method.note.MvcUriComponentsBuilder; import com.bezkoder.spring.files.upload.model.FileInfo; import com.bezkoder.spring.files.upload.model.ResponseMessage; import com.bezkoder.spring.files.upload.service.FilesStorageService; @Controller @CrossOrigin("http://localhost:8081") public form FilesController {   @Autowired   FilesStorageService storageService;   @PostMapping("/upload")   public ResponseEntity<ResponseMessage> uploadFile(@RequestParam("file") MultipartFile file) {     String message = "";     try {       storageService.salvage(file);       message = "Uploaded the file successfully: " + file.getOriginalFilename();       return ResponseEntity.status(HttpStatus.OK).body(new ResponseMessage(message));     } catch (Exception e) {       message = "Could non upload the file: " + file.getOriginalFilename() + "!";       return ResponseEntity.status(HttpStatus.EXPECTATION_FAILED).trunk(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.grade, "getFile", path.getFileName().toString()).build().toString();       return new FileInfo(filename, url);     }).collect(Collectors.toList());     return ResponseEntity.status(HttpStatus.OK).trunk(fileInfos);   }   @GetMapping("/files/{filename:.+}")   @ResponseBody   public ResponseEntity<Resources> getFile(@PathVariable String filename) {     Resource file = storageService.load(filename);     return ResponseEntity.ok()         .header(HttpHeaders.CONTENT_DISPOSITION, "zipper; filename=\"" + file.getFilename() + "\"").trunk(file);   } }                  

– @CrossOrigin is for configuring immune origins.
– @Controller note is used to ascertain a controller.
– @GetMapping and @PostMapping notation is for mapping HTTP Get & POST requests onto specific handler methods:

• POST /upload: uploadFile()
• Become /files: getListFiles()
• GET /files/[filename]: getFile()

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

Configure Multipart File for Servlet

Permit's ascertain the maximum file size that can exist uploaded in application.properties as post-obit:

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

– leap.servlet.multipart.max-file-size: max file size for each request.
– spring.servlet.multipart.max-request-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 system volition throw MaxUploadSizeExceededException and we're gonna use @ControllerAdvice with @ExceptionHandlernote for handling the exceptions.

exception/FileUploadExceptionAdvice.coffee

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

Initialize Storage

Nosotros need to run init() method of FilesStorageService (and besides deleteAll() if necessary). And so open SpringBootUploadFilesApplication.coffee and implement CommandLineRunner for run() method like this:

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

Run & Test

Run Spring Kick application with command: mvn jump-boot:run.
Refresh the project directory and you will see uploads binder inside it.

Let'south use Postman to make some requests.

– Upload some files:

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

– Check uploads binder:

– Retrieve list of Files' information:

– Now y'all can download any file from i of the paths above.
For example: http://localhost:8080/files/bezkoder.png.

Determination

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

Following tutorials explain how to build Front end-end Apps to work with our Bound Boot Server:
– Angular 8 Client / Athwart 10 Client / Angular xi Customer / Angular 12
– Angular Textile 12
– Vue Client / Vuetify Customer
– React Customer / React Hooks Client
– Material UI Client
– React Image Upload with Preview
– Axios Client

For multiple Files at one time:
How to upload multiple files in Java Leap Boot

Yous can likewise know way to upload an Excel/CSV file and store the content in MySQL database with the post:
– Bound Kicking: Upload/Import Excel file data into MySQL Database
– Leap Boot: Upload/Import CSV file information into MySQL Database

If you want to store files in database like this:

You can find educational activity at:
Leap Boot Upload/Download File to/from Database example

Happy Learning! Come across you once again.

Further Reading

• Multipart Content-Blazon

Source Code

You lot can find the complete source code for this tutorial on Github.

valdezsompere.blogspot.com

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

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