Returning custom object with InputStream parameter in JAX-RS

Question

I'm storing objects of type Binary in a database and I have a JAX-RS web service that can retrieve them by their ID.

public class Binary {
    private InputStream data;
    private String id;
    private String name;
    private String description;

    ... // constructors/getters/setters
}

I was able to get it working with this code:

@GET
@Path("{id}")
@Produces(MediaType.MULTIPART_FORM_DATA)
Response getBinary(@PathParam("id") String id) {
    Binary binary = ... // get binary from database
    FormDataMultiPart multipart = new FormDataMultiPart();
    multipart.field("name", binary.getName());
    multipart.field("description", binary.getDescription());
    multipart.field("data", app.getData(), 
    MediaType.APPLICATION_OCTET_STREAM_TYPE);

    return multipart;
}

I don't like wrapping the values in a FormDataMultiPart and unwrapping them in the client code. I want to directly return the Binary object like this:

@GET
@Path("{id}")
@Produces(/* ? */)
Binary getBinary(@PathParam("id") String id) {
    Binary binary = ... // get binary from database

    return binary;
}

I can't use XML or JSON representation because of the InputStream parameter. I'd appreciate any help of how to deal with this problem. Thanks!

Answer 1

If you have data as InputStream you will have problems having to reset every time you read from the InputStream. Better have it as byte[].

If you are using jackson you can then return like:

@GET
@Path("{id}")
@Produces(/* ? */)
public Response get(String documentId) {
    Binary binary = ... // get binary from database
    return Response.ok(binary).build();
}

you can test it with:

CloseableHttpClient httpclient = HttpClients.createDefault();
ObjectMapper mapper = new ObjectMapper();
TestObj obj = new TestObj();
obj.setFile(IOUtils.toByteArray(new FileInputStream(new File("C:\\download.jpg"))));
obj.setMimetype("image/jpeg");
obj.setDescription("asd");
String jsonInString = mapper.writeValueAsString(obj);
HttpPost httpPost = new HttpPost("http://localhost:8080/url");
httpPost.setHeader("Authorization", "Bearer asdf");
httpPost.setHeader("Content-type", "application/json");
StringEntity se = new StringEntity(jsonInString);
httpPost.setEntity(se);
System.out.println(httpPost.toString());
CloseableHttpResponse response2 = httpclient.execute(httpPost);
try {
    System.out.println("!!!! " + jsonInString);
    System.out.println("!!!! " + se.toString());
    System.out.println("!!!! " + response2.getStatusLine());
    HttpEntity entity2 = response2.getEntity();
    EntityUtils.consume(entity2);
} finally {
    response2.close();
}