I work on spring boot and angular I made an authentication based on spring security I tested with postman and everything works fine, but when I use angular it does not work after debugging I noticed that request. getParameter("username") return null, the error is probably on the angular request, please can someone help me

 @Override
 public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response)
 throws AuthenticationException {

    // TODO Auto-generated method stub
    String username = request.getParameter("username");
    System.out.println(username);
    String password = request.getParameter("password");
    System.out.println(password);

    UsernamePasswordAuthenticationToken authToken = new UsernamePasswordAuthenticationToken(username, password);
    return authManager.authenticate(authToken);
 }

//req angular

login(params:any) : Observable<any> {
      let username=params.username as string
      let password=params.password as string
     
     const FORM_URL = {
      headers:{
        'Content-Type': 'application/json'
      }
     }
    
     return this.http.post<any>(`${this.adresse+'/login'}`,{ 
      'username':username,
      'password':password
      }, FORM_URL)}
 }