jdownload

JVM	Platform	Status
OpenJDK (Temurin) Current	Linux
OpenJDK (Temurin) LTS	Linux
OpenJDK (Temurin) Current	Windows
OpenJDK (Temurin) LTS	Windows

jdownload

The jdownload package implements a trivial wrapper around the JDK HTTP client providing downloads, checksum verification, and transfer statistics.

Features

• Trivial HTTP file downloader providing transfer statistics.
• Automatic checksum verification for downloads.
• Low dependency: Requires Java 21 and uses SLF4J for logging.
• High coverage test suite.
• OSGi-ready.
• JPMS-ready.
• ISC license.

Usage

HttpClient client;
URI targetURI;
Path outputFile;
Path outputFileTemp;

Download a file from targetURI, writing the data temporarily to outputFileTemp and then atomically replacing outputFile with outputFileTemp if the download succeeds:

final var result =
  JDownloadRequests.builder(client, targetURI, outputFile, outputFileTemp)
    .build()
    .execute();

Perform the same download operation, but receive transfer statistics during the download:

Consumer<STTransferStatistics> receiver;

final var result =
  JDownloadRequests.builder(client, targetURI, outputFile, outputFileTemp)
    .setTransferStatisticsReceiver(receiver)
    .build()
    .execute();

Perform the same download operation, but reject the download if the resulting file does not match the given checksum:

final byte[] checksum =
  HexFormat.of()
   .parseHex("2d8bd7d9bb5f85ba643f0110d50cb506a1fe439e769a22503193ea6046bb87f7");

final var result =
  JDownloadRequests.builder(client, targetURI, outputFile, outputFileTemp)
    .setChecksumStatically("SHA-256", checksum)
    .build()
    .execute();

Perform the same download operation, but reject the download if the resulting file does not match the checksum obtained from the given checksum URI:

Consumer<STTransferStatistics> receiver;
Path checksumFile;
Path checksumFileTemp;
URI checksumURI;

final var result =
  JDownloadRequests.builder(client, targetURI, outputFile, outputFileTemp)
    .setChecksumFromURL(checksumURI, "SHA-256", checksumFile, checksumFileTemp, receiver)
    .build()
    .execute();