Spring Boot MongoRepository空指针异常

Question

我对spring有点陌生，我遇到了一个空指针异常。我认为@autowired在我的MongoRepository上不起作用。由于某种原因，当我试了一些例子时，它起作用了。（运行函数中注释掉的代码起作用）

这是我得到的错误：

2016-05-20 02:31:20.877错误6272---[nio-8080-exec-2]O.A.C.C.C.[.[.[/].[dispatcherServlet]:路径为[]的上下文中servlet[dispatcherServlet]的servlet.service（）引发异常[请求处理失败；嵌套异常为java.lang.NullPointerException]并具有根本原因

java.lang.NullPointerException：com.applesauce.service.customerservice.AddCustomer(CustomerService.java:24)~[classes/:na]

你们能帮我看看吗？另外，如果我在最佳实践方面做错了什么，请让我知道。如果您需要更多的信息，请询问！

com.AppleSauce.Controller

@RestController 
@RequestMapping("/customer")
public class CustomerController {

private CustomerService customerService = new CustomerService();

@RequestMapping(value = "/addcustomer", method = RequestMethod.GET)
public Customer addCustomer(@RequestParam("firstName") String fName,
                         @RequestParam("lastName") String lName,
                         @RequestParam("email") String email,
                         @RequestParam("phoneNumber") String phoneNumber,
                         @RequestParam("source") String source){
    return customerService.addCustomer(new Customer(fName,lName,email,phoneNumber,source));
}
}

com.applesauce.repository

@Repository
public interface CustomerRepository extends MongoRepository<Customer, String> {

public Customer findByFirstName(String firstName);
public List<Customer> findByLastName(String lastName);
}

com.applesauce.service

@EnableMongoRepositories(basePackages = "com.applesauce.repository")
public class CustomerService {

@Autowired
private CustomerRepository repository;

public Customer addCustomer(Customer customer){

    repository.save(customer);

    return customer;
}
}

Answer 1

Xtreme Biker的意思是，您应该为您的CustomerService添加@service注释，如下所示：

@EnableMongoRepositories(basePackages = "com.applesauce.repository")
@Service
public class CustomerService {
...
}

此外，如果您希望Spring会考虑使用new operator创建服务，那么您永远不会希望使用new operator创建服务。在CustomerController中,更改初始化行：

private CustomerService customerService = new CustomerService();

致：

@Autowired
private CustomerService customerService;