Spring Boot下如何自定义Repository中的DAO方法

import java.util.Date;
import javax.persistence.Column;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.MappedSuperclass;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import javax.persistence.Version;
@MappedSuperclass
public abstract class BaseEntity implements java.io.Serializable {
 private static final long serialVersionUID = -2420979951576787924L;
 @Id
 @GeneratedValue(strategy=GenerationType.IDENTITY)
 @Column(name = "ID")
 private Long id;
 @Version
 private Long version;
 @Temporal(TemporalType.TIMESTAMP)
 @Column(name = "CREATE_TIME",columnDefinition="timestamp default CURRENT_TIMESTAMP")
 private Date createTime;
 @Temporal(TemporalType.TIMESTAMP)
 @Column(name = "UPDATE_TIME",columnDefinition="timestamp default CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP")
 private Date updateTime;
}

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;
import lombok.Data;
@Entity
@Table(name="mycity")
@Data
public class City extends BaseEntity {
 private static final long serialVersionUID = -7510771121759944670L;
 @Column(name="Name")
 private String name;
 @Column(name="country_code")
 private String countryCode;
 @Column
 private String district;
 @Column
 private int population;
}

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import com.rose.money.City;
@Repository
public interface CityRepository extends JpaRepository<City, Long>, CityRepositoryCustom{
}

public interface CityRepositoryCustom {
 public void testAA();
}

import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import org.springframework.beans.factory.annotation.Autowired;
public class CityRepositoryImpl implements CityRepositoryCustom {
 @Autowired
 @PersistenceContext
 private EntityManager entityManager;
 @Override
 public void testAA() {
  List<Object[]> cities = entityManager.createNativeQuery("select id, name, district from mycity").getResultList();
  for (Object[] objs : cities) {
   System.out.print("location 1:" + objs[0]);
   System.out.print("location 2:" + objs[1]);
   System.out.print("location 3:" + objs[2]);
  }
 }
}

spring.application.name=custom jpa
spring.jpa.database=MYSQL
spring.datasource.username=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://localhost:3306/world?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&useSSL=true
spring.jpa.hibernate.naming.strategy=org.hibernate.cfg.ImprovedNamingStrategy 
spring.jpa.show-sql=true

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import com.rose.money.repository.CityRepository;
@RunWith(SpringRunner.class)
@SpringBootTest
public class CustomjpaApplicationTests {
 @Autowired
 private CityRepository cityRepo;
 @Test
 public void contextLoads() {
  City city = cityRepo.findOne(1l);
  System.out.println("city=>" + city);
  cityRepo.testAA();
 }
}