我下载并成功运行了该项目：
https://github.com/spring-guides/gs-accessing-data-mongodb
在文件上：
定义了接口access_token：
CustomerRepository在文件上使用的
方法内：import java.util.List;
import org.springframework.data.mongodb.repository.MongoRepository;
public interface CustomerRepository extends MongoRepository<Customer, String> {
public Customer findByFirstName(String firstName);
public List<Customer> findByLastName(String lastName);
}
：
Application / run我有2个问题：
接口中的这两个方法在哪里实现：@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);
}
}
？
系统如何知道要比较的字段（在CustomerRepository内），以便在使用这两种方法时获得正确的实例？
谢谢！