Request req =Request.create(Globals.webservice_Create4Terminal+"?sign="+aString, METHOD.POST);
	    		Header header = Header.create();
	    		header.set("Content-Type", "application/json; charset=utf-8");
	    		req.setHeader(header);
	    		req.setData(Json.toJson("{\"terminal\":\""+terminal+"\",\"company\":\""+company+"\",\"searchTime\":\""+searchTime+"\",\"timestamp\":\""+timestamp+"\"}"));
	    		Response response = Sender.create(req).setTimeout(10000).send();
	    		System.err.println(Json.toJson(response));

我是这样写的，但是他会显示未将对象引用设置到对象的实例，这种情况应该怎么解决啊