首先，你好。我有員工、地點(diǎn)、部門和工作類別。每個(gè)類都有自己的 JPA Repository 接口。我有一個(gè)服務(wù)類，我想在這個(gè)類中一一創(chuàng)建對(duì)象，用控制器調(diào)用這個(gè)方法并寫入數(shù)據(jù)庫(kù)。但我收到以下錯(cuò)誤。我該如何修復(fù)這個(gè)錯(cuò)誤？我哪里做錯(cuò)了，如果您能幫忙，我將不勝感激。項(xiàng)目結(jié)構(gòu)在這里服務(wù)@Servicepublic class MainService {? ? @Autowired? ? LocationsRepository locationsRepository;? ? @Autowired? ? JobsRepository jobsRepository;? ? @Autowired? ? EmployeesRepository employeesRepository;? ? @Autowired? ? DepartmentsRepository departmentsRepository;? ? public String generateManual() {? ? ? ? try {? ? ? ? ? ? Locations locations = new Locations();? ? ? ? ? ? locations.setCountry("Turkey");? ? ? ? ? ? locations.setCity("Istanbul");? ? ? ? ? ? locationsRepository.save(locations);? ? ? ? ? ? Jobs jobs = new Jobs();? ? ? ? ? ? jobs.setSalary(4000);? ? ? ? ? ? jobs.setTitle("Software Developer");? ? ? ? ? ? jobsRepository.save(jobs);? ? ? ? ? ? Employees employees = new Employees();? ? ? ? ? ? employees.setFirstName("Mutlu");? ? ? ? ? ? employees.setLastName("Eren");? ? ? ? ? ? employees.setJobs(jobs);? ? ? ? ? ? employeesRepository.save(employees);? ? ? ? ? ? Departments departments = new Departments();? ? ? ? ? ? departments.setName("IT");? ? ? ? ? ? departments.setLocations(locations);? ? ? ? ? ? List<Employees> empList = new ArrayList<>();? ? ? ? ? ? empList.add(employees);? ? ? ? ? ? departments.setEmployees(empList);? ? ? ? ? ? departmentsRepository.save(departments);? ? ? ? ? ? return "SUCCESS.";? ? ? ? }catch(Exception e) {? ? ? ? ? ? e.printStackTrace();? ? ? ? ? ? return "FAILED.";? ? ? ? }? ? }}控制器@RestControllerpublic class MainController {? ? @Autowired? ? MainService mainService;? ? @GetMapping("/generate")? ? public void generate() {? ? ? ? mainService.generateManual();? ? }}資源spring.datasource.url=jdbc:mysql://localhost:3306/companydb?useUnicode=true&characterEncoding=UTF-8&useLegacyDatetimeCode=false&serverTimezone=Turkeyspring.datasource.username=rootspring.datasource.password=