RESTful接口实现文件智能下载

/**
* download a resume
* @return ressume file
*/
@GET
@Path("resume")
@Produces({MediaType.APPLICATION_OCTET_STREAM})
public Response download(@QueryParam("id") @DefaultValue("0") int id) throws IOException {
log.info ("download method start");
log.info("resume id is: " + id);
Resume entityResume = em.find(Resume.class, id);

if (entityResume != null) {
String ext = ".docx";
String contentType = entityResume.getContentType();
if (Resume.DOC_CONTENT_TYPE.equals(contentType)) {
ext = ".doc";
}
else if (Resume.PDF_CONTENT_TYPE.equals(contentType)) {
ext = ".pdf";
}
byte[] content = entityResume.getContent();

response.setContentType(MediaType.APPLICATION_OCTET_STREAM);
response.setHeader("Content-Disposition", "attachment; filename=resume" + ext);
log.info ("download method end");
return Response.ok(content, MediaType.APPLICATION_OCTET_STREAM).build();
}
log.info ("download method end - noContent");
return Response.noContent().build();