How to call controller method from jsp using ajax - ajax

Question

I am using spring boot, maven 3.2.5.
I am working on simple maven webapp using spring boot following mvc pattern.
i am trying to call controller method from jsp suing ajax.
this is my jsp javascript method look like , which call the ajax call to call the controller method.
function listExistingUser()
{
alert("listExistingUser");
$.ajax({
type : "GET",
url : '${home}/loginController/listExistingUser',
dataType : "json",
crossDomain:true,
success : function(data) {
//console.log(data);
//alert(data.toString());
checkValidUser(data);
},
error : function(data) {
}
});
}
Bellow is my controller class.
#Controller
#RequestMapping("/loginController")
public class LoginController {
#Autowired
LoginService loginService;
#RequestMapping(value = "/listExistingUser", method = RequestMethod.GET)
#ResponseBody
public Object getAuthentication(#ModelAttribute("studentId") int studentId,
HttpServletRequest request, HttpServletResponse response)
{
System.out.println("listExistingUser is called in controller");
}
}
when I run my application, I am able to access login.jsp from the bellow url
http://localhost:9090/seperation-management/pages/login.jsp
when i hit submit button my jsp page javascript method is also getting called that is alert("listExistingUser");
but i am not able to called my controller method.
where I am making mistake. can anyone help me.

Answer 1

there's some changes to be made in the contoller method
#RequestMapping(value = "/listExistingUser", method = RequestMethod.GET)
#ResponseBody
public ResponseEntity<Object> getAuthentication(){
System.out.println("listExistingUser is called in controller");
return new ResponseEntity<Object>(object,HttpStatus.OK);
}
you dont need to have #modelAttribute annotation since you are not binding any object with the request. and it is a good practise to return ResponseEntity instead of returning an Object.
if you need to get an id from an incoming request
like this siteName/listExistingUser/1 then use this method.
#RequestMapping(value = "/listExistingUser/{id}", method = RequestMethod.GET)
#ResponseBody
public ResponseEntity<Object> getAuthentication(#PathVariable("id") int id){}
if you want to get values from a url like this
siteName/listExistingUser?id=1 then use this method instead.
#RequestMapping(value = "/listExistingUser", method = RequestMethod.GET)
#ResponseBody
public ResponseEntity<Object> getAuthentication(#RequestParam("id") int id){}

Answer 2

This example is working in my Application:
JSP:
<script type="text/javascript" charset="utf-8">
function getDesc() {
$.getJSON("desclist.json", {
sel1Id : $('select#COMPSNT_NM').val()
}, function(data) {
var html = '';
var len = data.length;
for (var i = 0; i < len; i++) {
html += '<option value="' + data[i] + '">'
+ data[i] + '</option>';
}
$('select#COMPSNT_DS').html(html);
});
}
$(document).ready(function() {
$('#COMPSNT_NM').change(function() {
getDesc();
});
});
</script>
Controller:
#RequestMapping(value = "desclist.json")
#ResponseStatus(HttpStatus.OK)
public #ResponseBody List<String> sectionList(#RequestParam(value = "sel1Id", required = true) String sel1Id,
ModelMap modelMap) {
List<PARAM_SEQ_2> list = new ArrayList<>();
List<String> list2 = new ArrayList<>();
list = paramSeq2Service.findByField2(sel1Id);
for (PARAM_SEQ_2 prm : list) {
list2.add(prm.getCOMPSNT_DS());
}
return list2;
}