response.body().string() 的值消失了

sendParams.put("signMsg",signService.signMsg(String.valueOf(sb),pricateKeyPath,password,charset));
FormBody.Builder form = new FormBody.Builder();
for (String key : sendParams.keySet()) {
form.add(key, sendParams.get(key));
}
RequestBody body = form.build();
logger.info("[tong 报关] formBody is {}", body.toString());
Request request = new Request.Builder()
.url(URL)
.post(body)
.build();
Response response;
try {
response=okHttpClient.newCall(request).execute();
String returnMsg=response.body().string();
if (response.isSuccessful()){
logger.info("baoguan seccuss is {}", returnMsg);
System.out.println("i am coming");
}else {
System.out.println("fail");
}

    } catch (IOException e) {
        e.printStackTrace();
    }
    return null;


        上图代码中response.isSuccessful() 方法执行成功,为什么我的日志打印出的信息为
        2019-05-14 11:07:57.430  INFO 11848 --- [           main] ALL                                      : Refunfquery seccuss is 

        resp后面没有信息,null也没有

debug 看 response 对象的信息，估计这个用法不对。