xUtils怎么post请求上传json数据

RequestParams requestParams =new RequestParams("http://"+ SpeechApp.url+"/interfaceAndroid/Project/AddServiceItemQuote");
ArrayList arrayList =new ArrayList<>();
arrayList.add(new Dingdan_Model("1","2","3","4","5"));
arrayList.add(new Dingdan_Model("2","2","3","4","5"));
arrayList.add(new Dingdan_Model("3","2","3","4","5"));
arrayList.add(new Dingdan_Model("4","2","3","4","5"));
arrayList.add(new Dingdan_Model("5","2","3","4","5"));
User user=new User(arrayList,"12345");
Gson g=new Gson();
String a=g.toJson(user);
requestParams.setAsJsonContent(true);
requestParams.setBodyContent(a);
requestParams.setCharset("utf-8");
x.http().post(requestParams, new Callback.CommonCallback() {
@Override
public void onSuccess(String result) {
System.out.println("result==" + result);
Toast.makeText(Wode_wenti.this,result,Toast.LENGTH_LONG).show();
}

@Override
public void onError(Throwable ex, boolean isOnCallback) {
System.out.println(ex.toString());
Toast.makeText(Wode_wenti.this,ex.toString(),Toast.LENGTH_LONG).show();
if (ex instanceof HttpException) { // 网络错误
HttpException httpEx = (HttpException) ex;
int responseCode = httpEx.getCode();
String responseMsg = httpEx.getMessage();
String errorResult = httpEx.getResult();
System.out.println("responseCode==" + responseCode);
System.out.println("responseMsg==" + responseMsg);
System.out.println("errorResult==" + errorResult);
}
}

@Override
public void onCancelled(CancelledException cex) {
}

@Override
public void onFinished() {
}
});