can t seem to find the backend controller

import axios from 'axios'

export async function registerForEventBackend(email: string, eventId: string): Promise<any> {
    try {
        const token = localStorage.getItem('token')

        const payload = {
            email,
            eventId,
            registeredAt: new Date().toISOString()
        }

        // Stuur POST met Authorization header
        const response = await axios.post(
            'http://localhost:8080/api/registrations',
            payload,
            {
                headers: {
                    Authorization: `Bearer ${token}`,  // Token meesturen
                    'Content-Type': 'application/json' // Zeker voor backend
                }
            }
        )

        return response.data

    } catch (error) {
        console.error('Fout bij registratie:', error)
        throw new Error('Registratie mislukt')
    }
}

import axios from 'axios'

export async function registerForEventBackend(email: string, eventId: string): Promise<any> {
    try {
        const token = localStorage.getItem('token')

        const payload = {
            email,
            eventId,
            registeredAt: new Date().toISOString()
        }

        // Stuur POST met Authorization header
        const response = await axios.post(
            'http://localhost:8080/api/registrations',
            payload,
            {
                headers: {
                    Authorization: `Bearer ${token}`,  // Token meesturen
                    'Content-Type': 'application/json' // Zeker voor backend
                }
            }
        )

        return response.data

    } catch (error) {
        console.error('Fout bij registratie:', error)
        throw new Error('Registratie mislukt')
    }
}

<script setup>
import { reactive } from 'vue'
import { registerForEventBackend } from '@/services/eventService'

const events = reactive([
  {
    id: 'event-1',
    title: 'Nieuwe Stad',
    description: 'De Bijlmer',
    location: 'Nieuwe Stad, Amersfoort',
    startTime: '2025-06-20T10:00:00',
    duration: 50,
    registrations: 0,
    email: '',
    emailError: ''
  },
  {
    id: 'event-2',
    title: 'Westerpark Festival',
    description: 'De grote fabriek',
    location: 'Westerpark, Amsterdam',
    startTime: '2025-07-08T18:00:00',
    duration: 40,
    registrations: 0,
    email: '',
    emailError: ''
  },
  {
    id: 'event-3',
    title: 'Golden Age',
    description: 'De gouden eeuw',
    location: 'Amsterdam',
    startTime: '2025-08-14T10:00:00',
    duration: 40,
    registrations: 0,
    email: '',
    emailError: ''
  }
])

async function registerForEvent(event) {
  event.emailError = ''

  if (!event.email.trim()) {
    event.emailError = 'Email adres is verplicht'
    return
  }

  if (!event.email.includes('@')) {
    event.emailError = 'Voer een geldig email adres in (@ ontbreekt)'
    return
  }

  try {
    await registerForEventBackend(event.email, event.id)
    event.registrations++
    event.email = ''
  } catch (err) {
    event.emailError = 'Registratie mislukt. Probeer opnieuw.'
  }
}
</script>

<script setup>
import { reactive } from 'vue'
import { registerForEventBackend } from '@/services/eventService'

const events = reactive([
  {
    id: 'event-1',
    title: 'Nieuwe Stad',
    description: 'De Bijlmer',
    location: 'Nieuwe Stad, Amersfoort',
    startTime: '2025-06-20T10:00:00',
    duration: 50,
    registrations: 0,
    email: '',
    emailError: ''
  },
  {
    id: 'event-2',
    title: 'Westerpark Festival',
    description: 'De grote fabriek',
    location: 'Westerpark, Amsterdam',
    startTime: '2025-07-08T18:00:00',
    duration: 40,
    registrations: 0,
    email: '',
    emailError: ''
  },
  {
    id: 'event-3',
    title: 'Golden Age',
    description: 'De gouden eeuw',
    location: 'Amsterdam',
    startTime: '2025-08-14T10:00:00',
    duration: 40,
    registrations: 0,
    email: '',
    emailError: ''
  }
])

async function registerForEvent(event) {
  event.emailError = ''

  if (!event.email.trim()) {
    event.emailError = 'Email adres is verplicht'
    return
  }

  if (!event.email.includes('@')) {
    event.emailError = 'Voer een geldig email adres in (@ ontbreekt)'
    return
  }

  try {
    await registerForEventBackend(event.email, event.id)
    event.registrations++
    event.email = ''
  } catch (err) {
    event.emailError = 'Registratie mislukt. Probeer opnieuw.'
  }
}
</script>

package com.example.backend.controller;

import com.example.backend.dto.EventRegistrationDTO;
import com.example.backend.services.EventService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api/registrations")
public class EventController {

    @Autowired
    private EventService eventService;

    @PostMapping
    public ResponseEntity<String> register(@RequestBody EventRegistrationDTO request) {
        eventService.registerForEvent(request);
        return ResponseEntity.ok("Registratie opgeslagen");
    }

    @GetMapping("/test")
    public ResponseEntity<String> test() {
        return ResponseEntity.ok("API werkt!");
    }
}

package com.example.backend.controller;

import com.example.backend.dto.EventRegistrationDTO;
import com.example.backend.services.EventService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api/registrations")
public class EventController {

    @Autowired
    private EventService eventService;

    @PostMapping
    public ResponseEntity<String> register(@RequestBody EventRegistrationDTO request) {
        eventService.registerForEvent(request);
        return ResponseEntity.ok("Registratie opgeslagen");
    }

    @GetMapping("/test")
    public ResponseEntity<String> test() {
        return ResponseEntity.ok("API werkt!");
    }
}

public interface UserRepository extends JpaRepository<CustomUser, Long> {
    Optional<CustomUser> findByEmail(String email);
    List<CustomUser> findAll();
} 

public interface UserRepository extends JpaRepository<CustomUser, Long> {
    Optional<CustomUser> findByEmail(String email);
    List<CustomUser> findAll();
} 

public interface EventRegistrationRepository extends JpaRepository<EventRegistration, UUID> {
} 

public interface EventRegistrationRepository extends JpaRepository<EventRegistration, UUID> {
} 

public class CorsConfig {
    @Bean
    public WebMvcConfigurer corsConfigurer() {
        return new WebMvcConfigurer() {
            @Override
            public void addCorsMappings(CorsRegistry registry) {
                registry.addMapping("/**")
                        .allowedOrigins("http://localhost:8081")
                        .allowedMethods("GET", "POST", "PUT", "DELETE", "OPTIONS")
                        .allowedHeaders("*");
            }
        };
    }
} 

public class CorsConfig {
    @Bean
    public WebMvcConfigurer corsConfigurer() {
        return new WebMvcConfigurer() {
            @Override
            public void addCorsMappings(CorsRegistry registry) {
                registry.addMapping("/**")
                        .allowedOrigins("http://localhost:8081")
                        .allowedMethods("GET", "POST", "PUT", "DELETE", "OPTIONS")
                        .allowedHeaders("*");
            }
        };
    }
}