1、说明
tus是一种基于HTTP的可恢复文件上传协议。可恢复意味着上传可以随时中断，并且可以恢复，而无需再次重新上传以前的数据。如果用户想要暂停，中断可能会自动发生，或者在网络问题或服务器中断的情况下意外发生。

tus-java-client是一个库，用于使用tus协议将文件上载到支持它的任何远程服务器。

该库还与Android平台兼容，使用API时无需任何修改即可使用。tus android客户端提供了额外的类，这些类可以在Java库之外使用。
源码地址: https://github.com/tus/tus-java-client

2、Maven依赖

<dependency>
  <groupId>io.tus.java.client</groupId>
  <artifactId>tus-java-client</artifactId>
  <version>0.4.3</version>
</dependency>

3、示例代码

// Create a new TusClient instance
TusClient client = new TusClient();

// Configure tus HTTP endpoint. This URL will be used for creating new uploads
// using the Creation extension
client.setUploadCreationURL(new URL("https://tusd.tusdemo.net/files"));

// Enable resumable uploads by storing the upload URL in memory
client.enableResuming(new TusURLMemoryStore());

// Open a file using which we will then create a TusUpload. If you do not have
// a File object, you can manually construct a TusUpload using an InputStream.
// See the documentation for more information.
File file = new File("./cute_kitten.png");
final TusUpload upload = new TusUpload(file);

System.out.println("Starting upload...");

// We wrap our uploading code in the TusExecutor class which will automatically catch
// exceptions and issue retries with small delays between them and take fully
// advantage of tus' resumability to offer more reliability.
// This step is optional but highly recommended.
TusExecutor executor = new TusExecutor() {
    @Override
    protected void makeAttempt() throws ProtocolException, IOException {
        // First try to resume an upload. If that's not possible we will create a new
        // upload and get a TusUploader in return. This class is responsible for opening
        // a connection to the remote server and doing the uploading.
        TusUploader uploader = client.resumeOrCreateUpload(upload);
        
        // Alternatively, if your tus server does not support the Creation extension
        // and you obtained an upload URL from another service, you can instruct
        // tus-java-client to upload to a specific URL. Please note that this is usually
        // _not_ necessary and only if the tus server does not support the Creation
        // extension. The Vimeo API would be an example where this method is needed.
        // TusUploader uploader = client.beginOrResumeUploadFromURL(upload, new URL("https://tus.server.net/files/my_file"));

        // Upload the file in chunks of 1KB sizes.
        uploader.setChunkSize(1024);

        // Upload the file as long as data is available. Once the
        // file has been fully uploaded the method will return -1
        do {
            // Calculate the progress using the total size of the uploading file and
            // the current offset.
            long totalBytes = upload.getSize();
            long bytesUploaded = uploader.getOffset();
            double progress = (double) bytesUploaded / totalBytes * 100;

            System.out.printf("Upload at %06.2f%%.\n", progress);
        } while(uploader.uploadChunk() > -1);

        // Allow the HTTP connection to be closed and cleaned up
        uploader.finish();

        System.out.println("Upload finished.");
        System.out.format("Upload available at: %s", uploader.getUploadURL().toString());
    }
};
executor.makeAttempts();