Spark（JAVA）：如何从http正文（音频文件）读取和保存数据文件？

Question

I kinda know how to see the data from the request, however I'm not sure how to handle it.

post("/", (req, res) -> {
        System.out.println(req.body());
        return "something";
    });

which shows me:

--1Wbh7zeSxsgY0YXI6wHO8nmxeVk4iV
Content-Disposition: form-data; name="file"; filename="1455896241350.m4a"
Content-Type: application/octet-stream
Content-Transfer-Encoding: binary

Data data ... etc

How to get the file attached with the body and save it in the server so later on I could use it?

*------------------------ * ------------------------ * ------------------------*

I've tired this code:

try {
        FileOutputStream fis = new FileOutputStream(new File("audio.m4a"));
        System.out.println("file created");
        try {
            int offset = 186;
            fis.write(req.bodyAsBytes(), offset, req.bodyAsBytes().length - offset);
            fis.close();
            System.out.println("file wrote");
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    System.out.println("done");

it worked fine for me, but it is static or hard-coded, I need it dynamic.

(Note/ I skiped the first 186 bytes which are the header of the http, so I need to get there dynamically not the hard-coded way)

Answer 1

get("/upload", (request, response) -> {
    return new ModelAndView(null, "upload.ftl");
}, new FreeMarkerEngine());

post("/upload", "multipart/form-data", ((request, response) -> {
    try {
        request.raw().setAttribute("org.eclipse.jetty.multipartConfig", 
            new MultipartConfigElement("/tmp", 100000000, 100000000, 1024));

        String filename = request.raw().getPart("file").getSubmittedFileName();

        Part uploadedFile = request.raw().getPart("file");
        try (final InputStream in = uploadedFile.getInputStream()) {
            Files.copy(in, Paths.get("/tmp/"+filename));
        }
        uploadedFile.delete();
    } catch (Exception e) {
        throw new RuntimeException(e);
    }

    return new ModelAndView(null, "upload.ftl");
}), new FreeMarkerEngine());

upload.ftl

<form action="/upload" enctype="multipart/form-data" method="post">
    <label for="file">File to send</label>
    <input type="file" name="file"><br>
    <input type="submit" value="Upload">
</form>

please excuse the hacky exception handling

this requires Spark 2.3

<dependency>
    <groupId>com.sparkjava</groupId>
    <artifactId>spark-core</artifactId>
    <version>2.3</version>
</dependency>