Help, How to manage the download of a file using $ .fileDownload from a controller?

I have a method that retrieves data from the form, and passes them as parameters to a service method to perform the query, this method returns a json response, and in the view sends me a message if there is data or not data in the query.

Now what I want to do is get the result of that query, and if there is data, I can download a file with that information and if not, show the message, for this I have two methods in the controller, one in the answer json and the other one that has the functionality of downloading the file, which I passed the list that I got from the first method

@RequestMapping(value="view/obtieneInfo")
@ResponseStatus(HttpStatus.OK)
@ResponseBody
public  JsonResponse obtieneInfor(@ResponseBody Factura fact, HttpServletRequest request, HttpServletResponse respons) throws ControlException{

JsonResponse response = new JsonResponse();
response.setExito(0);
response.setDatos(null);

try{
List<Factura> factList = obtieneInfoService.consultaDatos(id, cvePag, fecha);
if(factList !=null && !factList.isEmpty){
 response.setExito(1);
 response.setDatos(factList);

}else{
  log.info("Esta vacio");
}
}catch(ControlException e){
   throw new ControlException("Error", e);
}
return response;
}



@RequestMapping(value="view/obtieneArchivo")
public  void obtieneArchivo(HttpServletRequest request, HttpServletResponse response, @RequestParam ("factList") String [] factList ) throws ControlException{

try{

if(factList !=null){

 response.addHeader("Content-Type", "application/csv");
 response.addHeader("Content-Disposition", "attachment; filename=archivo.csv");

 PrintWriter out = response.getWriter();
            out.write("columna1,columna2,columna3");
            out.write("\n");

            for(String factu: factList){
                out.write(factu.toCSVRepresentation());
                out.write("\n");
            }
             out.flush();
             out.close();

}else{
  log.info("Esta vacio");
}
}catch(ControlException e){
   throw new ControlException("Error", e);
}
}

In my Invoice entity, I have this method:

public String toCSV(){
  StringBuilder builder = new StringBuilder();
  builder.append(getId()).append(“,”),
.
.
.
return builder.toString(),
}

and this is my view code, in which I have two functions, one is called obtienInf (), and what it does is to pass the json's response and validate whether there is data or not, and I have another function that it is called download (), which contains the url of my method 2 that performs the download of the file, and this function I send it to call inside obtainInf (), in the part where it validates that if there is data

function obtieneInf(){
    if(consultar()){
        if(!HelperForm.valido(consulta, validator)){
            return;

        }else{

            var data = Helper.obtenerJsonForm(consulta);
            var url="${pageContext.request.contextPath}/view/obtieneInfo";
            $.ajax({
                type:"POST",
                contentType: "application/json",
                url: url,
                data: data,
                dataType: 'json',
            success: function(response){
                if(response.exito==1){
                    HelperDialogo.mostrar("Si hay registros");
                  factList = response.datos;
                   descarga(factList);
                }else{
                    HelperDialogo.mostrar("No se encontraron registros");
                }

            },
            error: function(response){
                HelperDialogo.mostrarError(response);
            }

            });
        }
    }
}

function descarga(factList){

    var url="${pageContext.request.contextPath}/view/obtieneArchivo?factList=" +factList;
    $.fileDownload(url)
      .done(
        function(){
            Helper.muestraInf("Se descargo correctamente");
        }

      )
    .fail(
        function(){
            Helper.muestraInf("Ocurrio un  error en la descarga");
        }
    );
}
</script>
<form:form id="consulta" modelAttribute="consultaForm">
  <tr>
    <td><label>ID/label></td>
    <td><form: input type="text"  id="idPago" path="id"/></td>
   </tr>

   <tr>
    <td><label>CLAVE PAGO</label></td>
    <td><form: input type="text" id="clavePago" path="clavePago"/></td>
   </tr>

   <tr>


   <tr>
    <td><label>FECHA PAGO</label></td>
    <td><form: input type="text" id="fechaPago" path="fechaPago"/></td>
    <input type="button" onclick="obtieneInf()"></input>
   </tr>
</form:form>

and when filling out my form and clicking on the button, it sends me a message saying that if there is data, that is what I have in my function and then sends me another message that an error occurred in the download, which is of the download method () and throws me the error:

Failed to convrt value of type java.lang.String to required type util.List; nested exception is java.lang.IllegalStateException can not convert value of type String to required type com.mx.Entity

What is wrong, my method of the controller to pass the list ?, or how I do to download the file? is my download method ok, when in the url I have "$ {pageContext.request.contextPath} / view / getFile? factList=" + factList;

I need your help, thank you.