Serverless File Uploads for Java

Overview

In this guide, you’ll learn how to add Uploadcare file handling routines to your Java applications. It will take you no longer than 5 minutes to get started with file uploading: you’ll only need the single Uploadcare library dependency in place.

Get an Uploadcare Account

The first thing you need is an Uploadcare account, Sign Up if you haven’t done so before. Navigate to your dashboard, create a new project or pick an existing one. Proceed to the “API Keys” section and find your project keys. You will need them to create a client for Java API.

Setup

First, update your Java project configuration by adding the Uploadcare library dependency, java-artifact. Its latest version can be found here.

To build with Maven add to pom.xml:

<dependency>
  <groupId>com.uploadcare</groupId>
  <artifactId>uploadcare</artifactId>
  <version>3.2.0</version>
</dependency>

To build with Gradle add to Gradle build file:

compile 'com.uploadcare:uploadcare:3.2.0'

Below is a short introduction to Uploadcare basic concepts and the way to handle your files and settings on the per-account basis. You may choose to skip this section and go directly to uploading features.

Basic Concepts

One of the core Uploadcare concepts is the project. Uploadcare projects serve as separate environments holding different sets of files and settings within a single account. A project may be tailored to meet extra security requirements or accept files from a specific area of your application.

To access your project-specific data with Java, you need a client. In fact, the concept of the client is similar to the project: both are identified by a pair of API keys. You can learn more about Uploadcare projects here.

Create Client

You initialize an Uploadcare client by providing your Public and Secret API Keys:

Client client = new Client("publicKey", "secretKey");

Upload Files with FileUploader and UrlUploader

There are two ways to upload files with the Java Uploadcare library Uploader interface:

• With FileUploader by providing java.io.File, byte array or InputStream.
• With UrlUploader.

Below are a couple of simple examples. Of note is the com.uploadcare.api.File#getOriginalFileUrl method which we expect to return a combination of UUID and an original file name with removed whitespaces.

@Test
void uploadFileWithUrlUploader_uploadedAndRequestedFilesShouldMatch() throws UploadFailureException {
  Uploader uploader = new UrlUploader(client, URL);
  File uploadedFile = uploader.upload();
  String uploadedFileId = uploadedFile.getFileId();

  File requestedByIdFile = client.getFile(uploadedFileId);

  then(requestedByIdFile.hasOriginalFileUrl()).isTrue();
  then(requestedByIdFile.getOriginalFileUrl().getRawPath())
          .contains(uploadedFileId);
  then(requestedByIdFile.getOriginalFilename()).isEqualToIgnoringCase(SHUTTERSTOCK_FILE_NAME);
  then(requestedByIdFile.getMimeType()).isEqualTo("image/jpeg");
  then(requestedByIdFile.isRemoved()).isFalse();
  then(requestedByIdFile.isStored()).isTrue();
  then(requestedByIdFile.getUploadDate()).isInSameHourAs(new Date());
}

@Test
void uploadFileWithFileUploader_uploadedAndRequestedFilesShouldMatch()
    throws UploadFailureException {
  java.io.File localFile = new java.io.File(Optional.ofNullable(getClass().getClassLoader()
      .getResource(LOCAL_FILE_NAME)).map(java.net.URL::getFile)
      .orElseThrow(RuntimeException::new));
  Uploader uploader = new FileUploader(client, localFile);
  File uploadedFile = uploader.upload();
  String uploadedFileId = uploadedFile.getFileId();

  File requestedByIdFile = client.getFile(uploadedFileId);

  then(requestedByIdFile.hasOriginalFileUrl()).isTrue();
  then(requestedByIdFile.getOriginalFileUrl().getRawPath()).contains(uploadedFileId);
  then(requestedByIdFile.getOriginalFilename()).isEqualToIgnoringCase(LOCAL_FILE_NAME);
  then(requestedByIdFile.isRemoved()).isFalse();
  then(requestedByIdFile.isStored()).isTrue();
  then(requestedByIdFile.getUploadDate()).isInSameHourAs(new Date());
}

Manage Project Data and Files Within Your Account

// Print 10 file names uploaded after today's midnight and matching regexp
client.getFiles().asList()
        .stream()
        .map(f -> new Pair<>(f.getOriginalFilename(), f.getUploadDate()))
        .filter(p -> p.getValue().after(Date.from(todayMidnight))
                && p.getKey().matches(FILENAME_STARTING_WITH_LETTERS_AND_HAVING_EXTENSION))
        .limit(10)
        .forEach(System.out::println);

Conclusion

In this quick guide, we provided an overview of the Java Uploadcare library and its methods. Refer to the official Java library GitHub repo for further reading.