JSON response appended with extra properties using jQuery File-Upload plugin in Struts 2

Question

I'm using jQuery File-Upload plugin with Struts 2.

In my action I am populating the JSON object "results" and that's all I want my action to return.

But it is also including the plugin's file object as well which is an incomplete JSON and causing everything to break on my callbacks. (Please note that if I don't populate my result object then it will return a valid JSON "file" object.

Is there any way I could avoid returning the "file" JSON response? I just want my action to return only "results"

{
    "results": [
        {
            "ExcelPath": "/usr/test/test.xlsx",
            "ExcelName": "test.xlsx",
            "TestExcelStatus": "success"
        }
    ] 
}
{
    "file": {
        "absolute": true,
        "absoluteFile": null,
        "absolutePath": "\/usr\/local\/apache-tomcat-7.0.39\/temp"
    },
    "path": "\/usr\/local\/apache-tomcat-7.0.39\/temp\/up

My Action is as below:

org.json.JSONObject resp = new JSONObject();            
JSONArray resultsArray = new JSONArray();
resp.put("results",resultsArray);
JSONObject result = new JSONObject();           
result.put("TestExcelStatus", "success");
result.put("ExcelName", this.fileFileName);
result.put("ExcelPath", fileToCreate.getPath());
resultsArray.put(result);
    

servletResponse.reset();
servletResponse.setHeader("Content-Type","application/json; charset=UTF-8");
servletResponse.setHeader("CacheControl","no-cache");
servletResponse.setHeader("Pragma","no-cache");
servletResponse.setHeader("Expires","-1");
//resp.writeJSONString(out);
resp.write(servletResponse.getWriter());

I am expecting the below line to clear the existing JSON and only return my "results" JSON. But it is still returning every thing.

servletResponse.reset();

And the desired JSON response must be as below without a "file".

{
    "results": [
        {
            "ExcelPath": "/usr/test/test.xlsx",
            "ExcelName": "test.xlsx",
            "TestExcelStatus": "success"
        }
    ] 
}

Answer 1

The Struts action is always returning a result code that is used by the action invocation to execute a result configured to this action. I suspect that result is of type json.

If the action returning json result then by default the root property is initialized to the action instance or a model if you are using model-driven action.

It means that all public properties of the root object will be serialized to JSON. You can control this process with annotations placed on the properties, or configure the result with parameters to include/exclude some properties from the result.

Actually you only need to configure the root parameter of the result to return an object that you serialize to JSON. But because you are writing to response directly you can change the result code returned by the action to NONE. This is used by the actions that don't return any result.