Android http post 到 ASP.NET Web API 不插入数据

Question

我正在使用安卓系统。我想将数据发布到 ASP.NET Web API。我使用以下方法尝试了http post

HttpPost httpPost = new HttpPost(url);
httpPost.setHeader("content-type", "application/json");
httpPost.setHeader("Accept", "application/json");

// adding post params
if (params != null) {
    httpPost.setEntity(new UrlEncodedFormEntity(params));
}

Log.i("serrrrr",""+params);

httpResponse = httpClient.execute(httpPost);

我的名字值对看起来像

[attendance={"attendance_id":"0","Usr_Id":"5","Com_Id":"1","date":"12-11-2015","time_in":"04:41:41 pm","time_out":"","location_in":"my address","location_out":"","status_in":"true","status_out":"true","total_time":"","App_id":"1"}]

当我尝试将此数据发布到 web api 时，出现以下错误

{"Message":"发生错误。","ExceptionMessage":"对象引用未设置为对象的实例。","ExceptionType":"System.NullReferenceException","StackTrace":" at WebApplication.Areas.Json.Controllers.AttendancesController.PostAttendance(出勤)\r\n 在 lambda_method(Closure , Object , Object[] )\r\n 在 System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.c__DisplayClass10 .b__9（对象实例，Object[] 方法参数）\r\n 在 System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute（对象实例，Object[] 参数）\r\n 在 System.Web.Http.Controllers .ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary`2 arguments, CancellationToken cancelToken)\r\n--- System.Runtime.CompilerServices.TaskAwaiter 上一个引发异常的位置的堆栈跟踪结束---\r\n。 ThrowForNonSuccess(任务任务)\r\n 在 System.Runtime.CompilerServices.Ta skAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Controllers.ApiControllerActionInvoker.d__0.MoveNext()\r\n--- 堆栈跟踪从上一个引发异常的位置结束 ---\r \n 在 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）\r\n 在 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务）\r\n 在 System.Web.Http.Controllers.ActionFilterResult.d__2 .MoveNext()\r\n--- 从先前引发异常的位置结束堆栈跟踪 ---\r\n 在 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n 在 System. Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Dispatcher.HttpControllerDispatcher.d__1.MoveNext()"}

我该如何解决这个问题？发送参数有问题吗？

Answer 1

你的例子

[
    attendance={
        "attendance_id":"0",
        "Usr_Id":"5",
        "Com_Id":"1",
        "date":"12-11-2015",
        "time_in":"04:41:41 pm",
        "time_out":"",
        "location_in":"my address",
        "location_out":"",
        "status_in":"true",
        "status_out":"true",
        "total_time":"",
        "App_id":"1"
    }
]

JSON 无效，因为数组中有键值对。你可以在http://jsonlint.com/查看它

因此您的输入/发布数据无法反序列化，并且服务器端代码不会进行错误处理来捕获它（并且可以选择返回有意义的错误消息）。

修正您的输入。