2. Create and Import Spring Boot Project

• Project: Select Maven
• Java Version: 17(Default)
• Spring Boot Version: 3.04
• Group: net.javaguides.springboot
• Artifact: springboot-upload-download-file-rest-api-example
• Name: springboot-upload-download-file-rest-api-example
• Description: springboot-upload-download-file-rest-api-example
• Package Name: net.guides.springboot.springbootfileupload
• Packaging: jar (This is the default value)
• Dependencies: Web

<?xml version="1.0" encoding="UTF-8"?>
<project
 xmlns="http://maven.apache.org/POM/4.0.0"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 <modelVersion>4.0.0</modelVersion>
 <groupId>net.javaguides.springboot</groupId>
 <artifactId>springboot-upload-download-file-rest-api-example</artifactId>
 <version>0.0.1-SNAPSHOT</version>
 <packaging>jar</packaging>
 <name>springboot-upload-download-file-rest-api-example</name>
 <description>Demo project for Spring Boot</description>
 <parent>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-parent</artifactId>
 <version>3.0.4</version>
 <relativePath/>
 <!-- lookup parent from repository -->
 </parent>
 <properties>
 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
 <java.version>17</java.version>
 </properties>
 <dependencies>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-test</artifactId>
 <scope>test</scope>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-configuration-processor</artifactId>
 <optional>true</optional>
 </dependency>
 </dependencies>
 <build>
 <plugins>
 <plugin>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-maven-plugin</artifactId>
 </plugin>
 </plugins>
 </build>
</project>

## MULTIPART (MultipartProperties)
# Enable multipart uploads
spring.servlet.multipart.enabled=true
# Threshold after which files are written to disk.
spring.servlet.multipart.file-size-threshold=2KB
# Max file size.
spring.servlet.multipart.max-file-size=200MB
# Max Request Size
spring.servlet.multipart.max-request-size=215MB
## File Storage Properties
file.upload-dir=./uploads
server.port=8081

package net.javaguides.springboot.fileuploaddownload.property;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
@Component
@ConfigurationProperties(prefix = "file")
public class FileStorageProperties {
 private String uploadDir;
 public String getUploadDir() {
 return uploadDir;
 }
 public void setUploadDir(String uploadDir) {
 this.uploadDir = uploadDir;
 }
}

package net.javaguides.springboot.fileuploaddownload.controller;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
import net.javaguides.springboot.fileuploaddownload.payload.Response;
import net.javaguides.springboot.fileuploaddownload.service.FileStorageService;
@RestController
public class FileUploadController {
 @Autowired
 private FileStorageService fileStorageService;
 @PostMapping("/uploadFile")
 public Response uploadFile(@RequestParam("file") MultipartFile file) {
 String fileName = fileStorageService.storeFile(file);
 String fileDownloadUri = ServletUriComponentsBuilder.fromCurrentContextPath()
 .path("/downloadFile/")
 .path(fileName)
 .toUriString();
 return new Response(fileName, fileDownloadUri,
 file.getContentType(), file.getSize());
 }
 @PostMapping("/uploadMultipleFiles")
 public List < Response > uploadMultipleFiles(@RequestParam("files") MultipartFile[] files) {
 return Arrays.asList(files)
 .stream()
 .map(file - > uploadFile(file))
 .collect(Collectors.toList());
 }
}

package net.javaguides.springboot.fileuploaddownload.service;
import java.io.IOException;
import java.net.MalformedURLException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.Resource;
import org.springframework.core.io.UrlResource;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;
import org.springframework.web.multipart.MultipartFile;
import net.javaguides.springboot.fileuploaddownload.exception.FileStorageException;
import net.javaguides.springboot.fileuploaddownload.exception.FileNotFoundException;
import net.javaguides.springboot.fileuploaddownload.property.FileStorageProperties;
@Service
public class FileStorageService {
 private final Path fileStorageLocation;
 @Autowired
 public FileStorageService(FileStorageProperties fileStorageProperties) {
 this.fileStorageLocation = Paths.get(fileStorageProperties.getUploadDir())
 .toAbsolutePath().normalize();
 try {
 Files.createDirectories(this.fileStorageLocation);
 } catch (Exception ex) {
 throw new FileStorageException("Could not create the directory where the uploaded files will be stored.", ex);
 }
 }
 public String storeFile(MultipartFile file) {
 // Normalize file name
 String fileName = StringUtils.cleanPath(file.getOriginalFilename());
 try {
 // Check if the file's name contains invalid characters
 if (fileName.contains("..")) {
 throw new FileStorageException("Sorry! Filename contains invalid path sequence " + fileName);
 }
 // Copy file to the target location (Replacing existing file with the same name)
 Path targetLocation = this.fileStorageLocation.resolve(fileName);
 Files.copy(file.getInputStream(), targetLocation, StandardCopyOption.REPLACE_EXISTING);
 return fileName;
 } catch (IOException ex) {
 throw new FileStorageException("Could not store file " + fileName + ". Please try again!", ex);
 }
 }
 public Resource loadFileAsResource(String fileName) {
 try {
 Path filePath = this.fileStorageLocation.resolve(fileName).normalize();
 Resource resource = new UrlResource(filePath.toUri());
 if (resource.exists()) {
 return resource;
 } else {
 throw new FileNotFoundException("File not found " + fileName);
 }
 } catch (MalformedURLException ex) {
 throw new FileNotFoundException("File not found " + fileName, ex);
 }
 }
}

package net.javaguides.springboot.fileuploaddownload.exception;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.ResponseStatus;
@ResponseStatus(HttpStatus.NOT_FOUND)
public class FileNotFoundException extends RuntimeException {
 private static final long serialVersionUID = 1 L;
 public FileNotFoundException(String message) {
 super(message);
 }
 public FileNotFoundException(String message, Throwable cause) {
 super(message, cause);
 }
}

package net.javaguides.springboot.fileuploaddownload.exception;
public class FileStorageException extends RuntimeException {
 private static final long serialVersionUID = 1 L;
 public FileStorageException(String message) {
 super(message);
 }
 public FileStorageException(String message, Throwable cause) {
 super(message, cause);
 }
}

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