rest - Jersey REST 支持简历/媒体流

Question

我需要在 Jersey REST 上支持简历，我正在尝试这样做:

@Path("/helloworld")
public class RestServer {

@GET

@Path("say")
@Produces("audio/mp3")
public Response getMessage(@HeaderParam("Range") String r ) throws IOException{
    String str="/Users/dima/Music/crazy_town_-_butterfly.mp3";

    System.out.println(r);
    RandomAccessFile f=new RandomAccessFile(str, "r");

    int off=0;
    int to=(int)f.length();
    byte[] data ;
    if(r!=null){
        String from=r.split("=")[1].split("-")[0];
        String t=r.split("=")[1].split("-")[1];
        off=Integer.parseInt(from);
        to=Integer.parseInt(t);

    }
    data= new byte[to-off];
    f.readFully(data, off, to-off);

    ResponseBuilder res=Response.ok(data)
            .header("Accept-Ranges","bytes")
            .header("Content-Range:", "bytes "+off+"-"+to+"/"+data.length)
            .header("Pragma", "no-cache");;

            if(r==null){
                res=res.header("Content-Length", data.length);
            }
            f.close();

            Response ans=res.build();

            return ans;


}
}

我希望能够流式传输 mp3，以便浏览器可以寻找音乐，但在 safari 中它仍然无法正常工作。有任何想法吗？

Answer 1

这是我基于提供的解决方案的看法 here .它可以在不同的浏览器上正常工作。我也可以在 Safari 和其他浏览器中很好地寻找音乐。你可以在我的 Github 上找到示例项目 repository其中有更多细节。 Chrome 和 Safari 很好地利用范围 header 来流式传输媒体，您可以在请求/响应跟踪中看到它。

    @GET
    @Produces("audio/mp3")
    public Response streamAudio(@HeaderParam("Range") String range) throws Exception {
        return buildStream(audio, range);
    }

    private Response buildStream(final File asset, final String range) throws Exception {
        // range not requested : Firefox, Opera, IE do not send range headers
        if (range == null) {
            StreamingOutput streamer = new StreamingOutput() {
                @Override
                public void write(final OutputStream output) throws IOException, WebApplicationException {

                    final FileChannel inputChannel = new FileInputStream(asset).getChannel();
                    final WritableByteChannel outputChannel = Channels.newChannel(output);
                    try {
                        inputChannel.transferTo(0, inputChannel.size(), outputChannel);
                    } finally {
                        // closing the channels
                        inputChannel.close();
                        outputChannel.close();
                    }
                }
            };
            return Response.ok(streamer).header(HttpHeaders.CONTENT_LENGTH, asset.length()).build();
        }

        String[] ranges = range.split("=")[1].split("-");
        final int from = Integer.parseInt(ranges[0]);
        /**
         * Chunk media if the range upper bound is unspecified. Chrome sends "bytes=0-"
         */
        int to = chunk_size + from;
        if (to >= asset.length()) {
            to = (int) (asset.length() - 1);
        }
        if (ranges.length == 2) {
            to = Integer.parseInt(ranges[1]);
        }

        final String responseRange = String.format("bytes %d-%d/%d", from, to, asset.length());
        final RandomAccessFile raf = new RandomAccessFile(asset, "r");
        raf.seek(from);

        final int len = to - from + 1;
        final MediaStreamer streamer = new MediaStreamer(len, raf);
        Response.ResponseBuilder res = Response.status(Status.PARTIAL_CONTENT).entity(streamer)
                .header("Accept-Ranges", "bytes")
                .header("Content-Range", responseRange)
                .header(HttpHeaders.CONTENT_LENGTH, streamer.getLenth())
                .header(HttpHeaders.LAST_MODIFIED, new Date(asset.lastModified()));
        return res.build();
    }

这是 MediaStreamer 实现，用于在您的资源方法中流式传输输出。

public class MediaStreamer implements StreamingOutput {

    private int length;
    private RandomAccessFile raf;
    final byte[] buf = new byte[4096];

    public MediaStreamer(int length, RandomAccessFile raf) {
        this.length = length;
        this.raf = raf;
    }

    @Override
    public void write(OutputStream outputStream) throws IOException, WebApplicationException {
        try {
            while( length != 0) {
                int read = raf.read(buf, 0, buf.length > length ? length : buf.length);
                outputStream.write(buf, 0, read);
                length -= read;
            }
        } finally {
            raf.close();
        }
    }

    public int getLenth() {
        return length;
    }
}