SpringDataJPA之CrudRepository接口

@NoRepositoryBean
public interface CrudRepository<T, ID extends Serializable> extends Repository<T, ID> {
  <S extends T> S save(S entity);
  <S extends T> Iterable<S> save(Iterable<S> entities);
  T findOne(ID id);
  boolean exists(ID id);
  Iterable<T> findAll();
  Iterable<T> findAll(Iterable<ID> ids);
  long count();
  void delete(ID id);
  void delete(T entity);
  void delete(Iterable<? extends T> entities);
  void deleteAll();
}

/**
 * CrudRepository 接口使用
 * 定义的方法名称 参考文档定义
 */
public interface UserDao extends CrudRepository<Users,Integer> {
}

/**
 * @program: spring-data-jpa 
 * @description: 单元测试
 * @author: 波波烤鸭
 * @create: 2019-05-18 09:48
 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class TestDemo {
    @Autowired
    private UserDao usersDao;
    /**
     * 添加单条数据
     */
    @Test
    public void test1(){
        Users user = new Users();
        user.setUserage(21);
        user.setUsername("赵小丽");
        this.usersDao.save(user);
    }
    /**
     * 批量添加数据
     */
    @Test
    public void test2(){
        Users user = new Users();
        user.setUserage(21);
        user.setUsername("赵小丽");
        Users user1 = new Users();
        user1.setUserage(25);
        user1.setUsername("王小虎");
        List<Users> list= new ArrayList<>();
        list.add(user);
        list.add(user1);
        this.usersDao.save(list);
    }
    /**
     * 根据 ID 查询单条数据
     */
    @Test
    public void test3(){
        Users users = this.usersDao.findOne(13);
        System.out.println(users);
    }
    /**
     * 查询全部数据
     */
    @Test
    public void test4(){
        List<Users> list = (List<Users>)this.usersDao.findAll();
        for (Users users : list) {
            System.out.println(users);
        }
    }
    /**
     * 删除数据
     */
    @Test
    public void test5(){
        this.usersDao.delete(13);
    }
    /**
     * 更新数据 方式一
     */
    @Test
    public void test6(){
        Users user = this.usersDao.findOne(12);
        user.setUsername("王小红");
        this.usersDao.save(user);
    }
    /**
     * 更新数据 方式二
     */
    @Test
    @Transactional
    @Rollback(false)
    public void test7(){
        Users user = this.usersDao.findOne(12);//持久化状态的
        user.setUsername("王小小");
    }
}