How to extract a single file from a remote archive file?

URLConnection to the archive, get its input stream, wrap it in a ZipInputStream , and repeatedly call getNextEntry() 和 closeEntry() to iterate through all the entries in the file until you reach the one you want. Then you can read its data using ZipInputStream.read(...) .

Java代码看起来是这样的:

URL url = new URL("http://example.com/path/to/archive");
ZipInputStream zin = new ZipInputStream(url.getInputStream());
ZipEntry ze = zin.getNextEntry();
while (!ze.getName().equals(pathToFile)) {
    zin.closeEntry(); // not sure whether this is necessary
    ze = zin.getNextEntry();
}
byte[] bytes = new byte[ze.getSize()];
zin.read(bytes);

This is, of course, untested.

与这里的其他答案相反,我想指出zip条目是单独压缩的,因此(理论上)您不需要下载目录和条目本身以外的任何内容。服务器需要支持 Range HTTP header for this to work.

标准JAVA API只支持从本地文件和输入流读取zip文件。据我所知,没有从随机访问远程文件读取的规定。

Since you're using TrueZip, I recommend implementing de.schlichtherle.io.rof.ReadOnlyFile using Apache HTTP Client and creating a de.schlichtherle.util.zip.ZipFile 就这样。

这不会为压缩的tar档案提供任何优势,因为整个档案都被压缩在一起(不仅仅是使用一个输入流,当你有条目的时候就杀死它)。

Since TrueZIP 7.2, there is a new client API in the module TrueZIP Path. This is an implementation of an NIO.2 FileSystemProvider for JSE 7. Using this API, you can access HTTP URI as follows:

Path path = new TPath(new URI("http://acme.com/download/everything.tar.gz/README.TXT"));
try (InputStream in = Files.newInputStream(path)) {
    // Read archive entry contents here.
    ...
}

我不确定是否有一种方法可以在不首先下载整个文件的情况下从压缩包中提取单个文件。但是,如果您是承载zip文件的那个人,您可以创建一个Java servlet,它读取zip文件并在响应中返回请求的文件:

public class GetFileFromZIPServlet extends HttpServlet{
  @Override
  public void doGet(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException{
    String pathToFile = request.getParameter("pathToFile");

    byte fileBytes[];
    //get the bytes of the file from the ZIP

    //set the appropriate content type, maybe based on the file extension
    response.setContentType("...");

    //write file to the response
    response.getOutputStream().write(fileBytes);
  }
}