Nginx 利用 X-Accel-Redirect response.setHeader 控制文件下载

location / {
            proxy_redirect off;
            proxy_set_header Host  $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_pass http://backend;            
        }

location /file/ {
            internal;
            alias /usr/local/;
        }

<%
    String filename = request.getParameter("filename");
    response.setHeader("Content-Disposition", "attachment;filename="+filename);
    response.setHeader("Content-Type", "application/octet-stream");
    response.setHeader("X-Accel-Redirect", "/file/"+filename);
%>