else if (obj instanceof InputStream) {
            OutputStream out = resp.getOutputStream();
            Streams.writeAndClose(out, (InputStream) obj);
        }
else if (obj instanceof InputStream) {
            OutputStream out = resp.getOutputStream();
            Streams.writeAndClose(out, (InputStream) obj);
        }
else if ( obj instanceof InputStream ) { OutputStream out = resp . getOutputStream ( ) ; Streams . writeAndClose ( out , ( InputStream ) obj ) ; }
二进制流
二进制流