Extjs and Spring success handler - excel

Question

I'm building web application with ExtJs and Spring. With ExtJs I'm uploading excel file and with spring I parse it. Everything works fine, although my success handler in ExtJs code doesn't work. I read many examples about that, but I still can't solve this problem. I hope you guys will help me.
This is ExtJs upload file function:
uploadFile: function(value, fld){
var me = this;
var id = this.getTipasCombobox().getValue();
var record = this.getTipasCombobox().getStore().getById(id);
var timeId = this.getLaikotarpiaiCombo().getValue();
var timeRecord = this.getLaikotarpiaiCombo().getStore().getById(timeId);
var fp = this.getUploadBtn().up('form').getForm();
if(fp.isValid()){
fp.submit({
url: Turtas.Properties.getServicePath()+'/save/' + record.data.resource,
waitMsg: 'Failas yra įkeliamas, prašome palaukti...',
success: function(){
console.log("Upload completed");
me.storeSelection(record.data.resource, timeRecord.data.open, timeRecord.data.year, true, me.restrictedPage())
}
})
}
},
And this is my controller function which I use to parse Excel:
#RequestMapping(value="turtas/save/gelezinkeliai", method=RequestMethod.POST)
public String saveGelezinkeliaiFromExcel(HttpServletResponse response, #RequestParam("file") MultipartFile file){
if (file.getSize() != 0){
ReadExcelFileToList excelFile = new ReadExcelFileToList();
List<Gelezinkeliai> gelezinkeliai = new ArrayList<Gelezinkeliai>();
gelezinkeliai = excelFile.readExcelData(/*fileName*/ file);
gelezinkeliai.remove(0);
Laikotarpis laikotarpis = new Laikotarpis();
laikotarpis = laikotarpiaiService.findById(2014);
for (GelezinkeliaiRest delGelezinkelis : service.getItems(2014, true, false)){
service.delete(delGelezinkelis);
}
List<Gelezinkeliai> finalGelezinkeliai = new ArrayList<Gelezinkeliai>();
for (Gelezinkeliai gelezinkelis : gelezinkeliai){
gelezinkelis.setLaikotarpis(laikotarpis);
finalGelezinkeliai.add(gelezinkelis);
GelezinkeliaiRest gelezinkeliaiRest = new GelezinkeliaiRest();
gelezinkeliaiRest.fromGelezinkeliai(gelezinkelis);
service.save(gelezinkeliaiRest, false);
}
response.setContentType("text/html");
return "{\"success\":true}";
}
else {
return "{\"success\":false}";
}
}
Response content-type is text/html and response is:
{"success":true}
If I manually reload page or store, data is updated, so functions work properly, but i want to catch event when the request ends, to reload store automatically. I have no idea what's wrong. Thanks for responses in advance!