休息下载文件204无内容

Question

我有一个简单的休息服务，应该下载到png图像。

以下是代码：

@POST() 
@Path(value= "/download")

@Produces( {"image/jpeg", "image/png", "image/bmp", "image/gif", "image/tiff"} )
@Consumes( {MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML} )
public Response downloadImage(ChatDownloadFileRequest input) {
        ResponseBuilder response = null;            
        Image img = (Image)em2.createNamedQuery("Image.findByMessageId")
                      .setParameter("messageId", request.getMessageId())
                      .setHint("org.hibernate.cacheable", true)
                      .getSingleResult();

            String imgPath = img.getPath();

            File file = new File( imgPath );

            response = Response.ok((Object)file);

            String fileName = file.getName();
            response.header("Content-Disposition", "attachment; filename=" + fileName);

            return response.build(); 
}

当我拨打电话时，答案是204 No Content。

感谢所有

问候。