将JSON对象从Android客户端传递到CCF中的CCF Restful服务

Question

I have an android client which sends data in JSON object form to my server. My server is implemented by WCF acting as a RESTful service written in C#. I have a class called "User" in my WCF and I want to perform login action in android client. But when I post my object in JSON format to WCF service, I get a Null object (in Wrapped config) or I get an object which fields are null (in Bare config). Does anyone have a solution for this?

Here is a sample of generated JSON by my client which :

{"User":{"UserName":"123","Pass":"123","Device":"123"}}

This is my WCF Interface code :

    [OperationContract]
    [WebInvoke(Method = "POST",
        UriTemplate = "Login",
        BodyStyle = WebMessageBodyStyle.Wrapped,
        ResponseFormat = WebMessageFormat.Json,
        RequestFormat = WebMessageFormat.Json
      )]
    string Login(User user);

And this is my App.Config :

<system.serviceModel>
<services>
  <service behaviorConfiguration="CityManService.TrackingBehavior"
    name="CityManService.Tracking">
    <endpoint address="" behaviorConfiguration="json" binding="webHttpBinding"
      contract="CityManService.ITrackingService">
      <identity>
        <dns value="localhost" />
      </identity>
    </endpoint>
    <host>
      <baseAddresses>
        <add baseAddress="http://localhost:8731/CityManService/Tracking/" />
      </baseAddresses>
    </host>
  </service>
</services>
<behaviors>
  <endpointBehaviors>
    <behavior name="json">
      <webHttp />
    </behavior>
  </endpointBehaviors>
  <serviceBehaviors>
    <behavior name="CityManService.TrackingBehavior">
      <serviceMetadata httpGetEnabled="true" />
      <serviceDebug includeExceptionDetailInFaults="false" />
    </behavior>
  </serviceBehaviors>
</behaviors>

And Finally this is my client(android) code:

HttpPost request = new HttpPost("http://localhost:8731/CityManService/Tracking/Login");
request.setHeader("Accept", "application/json");
request.setHeader("Content-type", "application/json");

// Build JSON string
JSONStringer userJson = new JSONStringer()
    .object()
       .key("User")
          .object()
         .key("UserName").value(username.getText().toString())                                                                                                                                                        .key("Pass").value(password.getText().toString())                                                     .key("Device").value(password.getText().toString())
          .endObject()
       .endObject();

StringEntity entity = new StringEntity(userJson.toString(),"UTF-8");                                                
entity.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
entity.setContentType("application/json");

request.setEntity(entity);

// Send request to WCF service
DefaultHttpClient httpClient = new DefaultHttpClient();             
HttpResponse response = httpClient.execute(request);

Answer 1

The name of the wrapper should be the parameter name, not the type name. In your service, the operation is defined as

[WebInvoke(...)] 
string Login(User user);

So the input should be passed as

{"user":{"UserName":"123","Pass":"123","Device":"123"}}

(notice the lowercase "user" object name).