为什么当我运行我的迷你spring启动项目时，与mongodb的连接会关闭？

Question

我是一个初学者（顺便说一下：）

错误如下：

org.mongodb.driver.connection: Closed connection [connectionId{localValue:3, serverValue:4}] to localhost:27017 because the pool has been closed

我的主要课程是：

@SpringBootApplication
public class MangoApplication implements CommandLineRunner {

    @Autowired
    private CustomerRepository repository;
    public static void main(String[] args) {
        SpringApplication.run(MangoApplication.class, args);
    }
    @Override
    public void run(String... args) throws Exception {

        repository.deleteAll();

        // save a couple of customers
        repository.save(new Customer("Alice", "Smith"));
        repository.save(new Customer("Bob", "Smith"));

        // fetch all customers
        System.out.println("Customers found with findAll():");
        System.out.println("-------------------------------");
        for (Customer customer : repository.findAll()) {
            System.out.println(customer);
        }
        System.out.println();

        // fetch an individual customer
        System.out.println("Customer found with findByFirstName('Alice'):");
        System.out.println("--------------------------------");
        System.out.println(repository.findByFirstName("Alice"));

        System.out.println("Customers found with findByLastName('Smith'):");
        System.out.println("--------------------------------");
        for (Customer customer : repository.findByLastName("Smith")) {
            System.out.println(customer);
        }

    }

}

我的CustomerRepository接口：

public interface CustomerRepository extends MongoRepository<Customer, String> {
    public Customer findByFirstName(String firstName);
    public List<Customer> findByLastName(String lastName);
}

Answer 1

添加mongoClient bean。

@Bean
public MongoClient mongoClient(){
    return new MongoClient( "localhost" , 27017 );
}