public interface UserRepository extends JpaRepository<User, Long> {
}

@Test
public void testBaseQuery() throws Exception {
    User user=new User();
    userRepository.findAll();
    userRepository.findOne(1l);
    userRepository.save(user);
    userRepository.delete(user);
    userRepository.count();
    userRepository.exists(1l);
    // ...
}

class People{
       private String firstName;
       private String lastName;
}

findByLastNameAndFirstName(String lastName,String firstName);

Page<UserModel> findByName(String name, Pageable pageable);
List<UserModel> findByName(String name, Sort sort);

@Test
public void testPageQuery() throws Exception {
    int page=1,size=10;
    Sort sort = new Sort(Direction.DESC, "id");
    Pageable pageable = new PageRequest(page, size, sort);
    userRepository.findALL(pageable);
    userRepository.findByUserName("testName", pageable);
}

@NamedQuery(name = "UserModel.findByAge",query = "select o from UserModel o where o.age >= ?1")

public List<UserModel> findByAge(int age);

@Query(value="select * from tbl_user where name like %?1" ,nativeQuery=true)
public List<UserModel> findByUuidOrAge(String name);

@Query(value="select o from UserModel o where o.name like %:nn")
public List<UserModel> findByUuidOrAge(@Param("nn") String name);

User findFirstByOrderByLastnameAsc();
User findTopByOrderByAgeDesc();
Page<User> queryFirst10ByLastname(String lastname, Pageable pageable);
List<User> findFirst10ByLastname(String lastname, Sort sort);
List<User> findTop10ByLastname(String lastname, Pageable pageable);

public interface HotelSummary {
    City getCity();
    String getName();
    Double getAverageRating();
    default Integer getAverageRatingRounded() {
        return getAverageRating() == null ? null : (int) Math.round(getAverageRating());
    }
}

@Query("select h.city as city, h.name as name, avg(r.rating) as averageRating "
        + "from Hotel h left outer join h.reviews r where h.city = ?1 group by h")
Page<HotelSummary> findByCity(City city, Pageable pageable);
 
 
@Query("select h.name as name, avg(r.rating) as averageRating "
        + "from Hotel h left outer join h.reviews r  group by h")
Page<HotelSummary> findByCity(Pageable pageable);

Page<HotelSummary> hotels = this.hotelRepository.findByCity(new PageRequest(0, 10, Direction.ASC, "name"));
for(HotelSummary summay:hotels){
        System.out.println("Name" +summay.getName());
    }

@Modifying
@Query(value="update UserModel o set o.name=:newName where o.name like %:nn")
public int findByUuidOrAge(@Param("nn") String name,@Param("newName") String newName);

@Query(value = "delete from r_upa where user_id= ?1 and point_indecs_id in (?2)", nativeQuery = true)
@Modifying
void deleteByUserAndPointIndecs(Long uid, List<Long> hids);

@NoRepositoryBean
public interface JpaRepository<T, ID> extends PagingAndSortingRepository<T, ID>, QueryByExampleExecutor<T> {
    
    /**
  * Deletes the given entities in a batch which means it will create a single {@link Query}. Assume that we will clear
  * the {@link javax.persistence.EntityManager} after the call.
  *
  * @param entities
     * 批量解綁多個，優(yōu)勢：只會形成一個SQL語句
  */
 void deleteInBatch(Iterable<T> entities);
 
 /**
  * Deletes all entities in a batch call.
  */
 void deleteAllInBatch();
 
   
}

@NoRepositoryBean
public interface CrudRepository<T, ID> extends Repository<T, ID> {
   
    /**
  * Deletes the entity with the given id.
  *
  * @param id must not be {@literal null}.
  * @throws IllegalArgumentException in case the given {@code id} is {@literal null}
  */
 void deleteById(ID id);
 
 /**
  * Deletes a given entity.
  *
  * @param entity
  * @throws IllegalArgumentException in case the given entity is {@literal null}.
  */
 void delete(T entity);
 
 /**
  * Deletes the given entities.
  *
  * @param entities
  * @throws IllegalArgumentException in case the given {@link Iterable} is {@literal null}.
  */
 void deleteAll(Iterable<? extends T> entities);
 
 /**
  * Deletes all entities managed by the repository.
  */
 void deleteAll();
}

@NoRepositoryBean
public interface JpaRepository<T, ID> extends PagingAndSortingRepository<T, ID>, QueryByExampleExecutor<T> {
 
 
 /*
  * (non-Javadoc)
  * @see org.springframework.data.repository.CrudRepository#save(java.lang.Iterable)
  */
 <S extends T> List<S> saveAll(Iterable<S> entities);
 
 /**
  * Flushes all pending changes to the database.
  */
 void flush();
 
 /**
  * Saves an entity and flushes changes instantly.
  *
  * @param entity
  * @return the saved entity
  */
 <S extends T> S saveAndFlush(S entity);
 
 
}

@NoRepositoryBean
public interface CrudRepository<T, ID> extends Repository<T, ID> {
 
 /**
  * Saves a given entity. Use the returned instance for further operations as the save operation might have changed the
  * entity instance completely.
  *
  * @param entity must not be {@literal null}.
  * @return the saved entity will never be {@literal null}.
  */
 <S extends T> S save(S entity);
 
 /**
  * Saves all given entities.
  *
  * @param entities must not be {@literal null}.
  * @return the saved entities will never be {@literal null}.
  * @throws IllegalArgumentException in case the given entity is {@literal null}.
  */
 <S extends T> Iterable<S> saveAll(Iterable<S> entities);
}

  @Transactional
    public <S extends T> List<S> save(Iterable<S> entities) {
        List<S> result = new ArrayList<S>();
        if (entities == null) {
            return result;
        }
        for (S entity : entities) {
            result.add(save(entity));
        }
        return result;
    }

@Transactional
    public <S extends T> S save(S entity) {
        if (entityInformation.isNew(entity)) {
            em.persist(entity);//是新的就插入
            return entity;
        } else {
            return em.merge(entity); //不是新的merge
        }
    }