Package com.google.cloud.storage.contrib.nio
This client library allows you to easily interact with Google Cloud Storage, using Java's standard file system API, introduced in Java 7.
How It Works
The simplest way to get started is withPaths
and Files
:
Path path = Paths.get(URI.create("gs://bucket/lolcat.csv"));
List<String> lines = Files.readAllLines(path, StandardCharsets.UTF_8);
For the complete source code see ReadAllLines.java.
If you want to configure the bucket per-environment, it might make more sense to use the
FileSystem
API:
FileSystem fs = FileSystems.getFileSystem(URI.create("gs://bucket"));
byte[] data = "hello world".getBytes(StandardCharsets.UTF_8);
Path path = fs.getPath("/object");
Files.write(path, data);
List<String> lines = Files.readAllLines(path, StandardCharsets.UTF_8);
For the complete source code see GetFileSystem.java.
You can also use InputStream
and OutputStream
for streaming:
Path path = Paths.get(URI.create("gs://bucket/lolcat.csv")); try (InputStream input = Files.newInputStream(path)) { // use input stream }
For the complete source code see CreateInputStream.java.
You can set various attributes using CloudStorageOptions
static helpers:
Path path = Paths.get(URI.create("gs://bucket/lolcat.csv")); Files.write(path, csvLines, StandardCharsets.UTF_8, withMimeType("text/csv; charset=UTF-8"), withoutCaching());
For the complete source code see WriteFileWithAttributes.java.
NOTE: Cloud Storage uses a flat namespace and therefore doesn't support real
directories. So this library supports what's known as "pseudo-directories". Any path that
includes a trailing slash, will be considered a directory. It will always be assumed to exist,
without performing any I/O. This allows you to do path manipulation in the same manner as you
would with the normal UNIX file system implementation. You can disable this feature with CloudStorageConfiguration.usePseudoDirectories()
.
Non-SPI Interface
If you don't want to rely on Java SPI, which requires a META-INF file in your jar generated by Google Auto, you can instantiate this file system directly as follows:
CloudStorageFileSystem fs = CloudStorageFileSystem.forBucket("bucket"); byte[] data = "hello world".getBytes(StandardCharsets.UTF_8); Path path = fs.getPath("/object"); Files.write(path, data); data = Files.readAllBytes(path);
For the complete source code see CreateCloudStorageFileSystem.java.
-
ClassDescriptionConfiguration for
CloudStorageFileSystem
instances.Builder forCloudStorageConfiguration
.Interface for attributes on a Cloud Storage file or pseudo-directory.Metadata view for a Google Cloud Storage object.Google Cloud StorageFileSystem
implementation.Google Cloud StorageFileSystemProvider
implementation.Exception reminding user that Cloud Storage objects can't be mutated.Main interface for file operation option classes related to Google Cloud Storage.Interface for Google Cloud Storage options that can be specified when copying files.Interface for Google Cloud Storage options that can be specified when opening files.Interface for Google Cloud Storage options that can be specified when opening or copying files.Helper class for specifying options when opening and copying Cloud Storage files.A Google Cloud Storage specific implementation of thejava.nio.file.Path
interface.Exception thrown when erroneously trying to operate on a path with a trailing slash.Simple counter class to keep track of retry and reopen attempts when StorageExceptions are encountered.SeekableByteChannelPrefetcher wraps an existing SeekableByteChannel to add prefetching.