Multipart File to file error - spring

Question

I want to upload a multipart file to AWS S3. So, i have to convert it.
But new File method needs a local location to get the file.
I am able to do in local. But running this code in every machine seems like a issue.
Please find both scenarios.
Working
private File convertMultiPartToFile(MultipartFile multipartFile) throws IOException {
File convFile = new File("C:\\Users\\" + multipartFile.getOriginalFilename());
multipartFile.transferTo(convFile);
return convFile;
}
Not working
private File convertMultiPartToFile(MultipartFile multipartFile) throws IOException {
File convFile = new File(multipartFile.getOriginalFilename());
multipartFile.transferTo(convFile);
return convFile;
}
Error received :
java.io.FileNotFoundException: newbusiness.jpg (Access is denied)
at java.io.FileOutputStream.open0(Native Method)
at java.io.FileOutputStream.open(FileOutputStream.java:270)
at java.io.FileOutputStream.<init>(FileOutputStream.java:213)
at java.io.FileOutputStream.<init>(FileOutputStream.java:162)

Answer 1

You could use Spring Content S3. This will hide the implementation details so you don't need to worry about them.
There are Spring Boot starter alternatives but as you are not using Spring Boot add the following dependency to your pom.xml
pom.xml
<dependency>
<groupId>com.github.paulcwarren</groupId>
<artifactId>spring-content-s3</artifactId>
<version>0.0.11</version>
</dependency>
Add the following configuration that creates a SimpleStorageResourceLoader bean:
#Configuration
#EnableS3Stores
public class S3Config {
#Autowired
private Environment env;
public Region region() {
return Region.getRegion(Regions.fromName(env.getProperty("AWS_REGION")));
}
#Bean
public BasicAWSCredentials basicAWSCredentials() {
return new BasicAWSCredentials(env.getProperty("AWS_ACCESS_KEY_ID"), env.getProperty("AWS_SECRET_KEY"));
}
#Bean
public AmazonS3 client(AWSCredentials awsCredentials) {
AmazonS3Client amazonS3Client = new AmazonS3Client(awsCredentials);
amazonS3Client.setRegion(region());
return amazonS3Client;
}
#Bean
public SimpleStorageResourceLoader simpleStorageResourceLoader(AmazonS3 client) {
return new SimpleStorageResourceLoader(client);
}
}
Create a "Store":
S3Store.java
public interface S3Store extends Store<String> {
}
Autowire this store into where you need to upload resources:
#Autowired
private S3Store store;
WritableResource r = (WritableResource)store.getResource(getId());
InputStream is = // plug your input stream in here
OutputStream os = r.getOutputStream();
IOUtils.copy(is, os);
is.close();
os.close();
When your application starts it will see the dependency on spring-content-s3 and your S3Store interface and inject an implementation for you, therefore, you don't need to worry about implementing this yourself.
IF you writing some sort of web application or microservice and you need a REST API then you can also add this dependency:
<dependency>
<groupId>com.github.paulcwarren</groupId>
<artifactId>spring-content-rest</artifactId>
<version>0.0.11</version>
</dependency>
Update your S3Config.java as follows:
#Configuration
#EnableS3Stores
#Import(RestConfiguration.class)
public class S3Config {
...
Update your store as follows:
S3Store.java
#StoreRestResource(path="s3docs")
public interface S3Store extends Store<String> {
}
Now when your application starts it will see your Store interface and also inject an #Controller implementation that will forward REST request onto your store. This replaces the autowiring code above obviously.
Then:
curl -X POST /s3docs/example-doc
with a multipart/form-data request will store the image in s3.
curl /s3docs/example-doc
will fetch it again and so on. This controller supports full CRUD and video streaming by the way.
If you want to associate this "content" with JPA Entity or something like that then you can have your S3Store extend AssociateStore or ContentStore and you have additional methods available that provide for associations.
There are a couple of getting started guides here. The s3 reference guide is here. And there is a tutorial video here. The coding bit starts about 1/2 way through.
HTH

Answer 2

Since it needs a temporary location to place files. Below code worked after deploying war on AWS.
private File convertMultiPartToFile(MultipartFile multipartFile) throws IOException {
File convFile = new File(System.getProperty("java.io.tmpdir") + System.getProperty("file.separator") +
multipartFile.getOriginalFilename());
multipartFile.transferTo(convFile);
return convFile;
}

Answer 3

You have problems with relative Paths
You can do this
public class UploadStackoverflow {
private String location = "upload-dir";
private Path rootLocation;
public File convertFile(MultipartFile file) throws IOException {
rootLocation = Paths.get(location);
Files.createDirectories(rootLocation);
String filename = StringUtils.cleanPath(file.getOriginalFilename());
InputStream inputStream = file.getInputStream();
Files.copy(inputStream, this.rootLocation.resolve(filename),
StandardCopyOption.REPLACE_EXISTING);
return new File(this.rootLocation.resolve(filename).toAbsolutePath().toString());
}
}