SpringBoot-JPA学习笔记

1. 添加依赖

   <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-data-jpa</artifactId>
   </dependency>
   

2. 添加数据源及JPA配置

   spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
   spring.datasource.url=jdbc:mysql://127.0.0.1:3306/springboot_study6?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT
   spring.datasource.username=root
   spring.datasource.password=root
   # config hibernate
   spring.jpa.hibernate.ddl-auto=update
   spring.jpa.show-sql=true
   

3. 编写Entity实体类

   @Entity@Data@NoArgsConstructor
   public class User {
         
         
       @Id
       // 主键策略
       //IDENTITY: 使用数据库表的主键策略
       @GeneratedValue(strategy = GenerationType.IDENTITY)
       private Integer id ;
       // 用户名称
       @Column
       private String name ;
       // 创建时间
       @Column(name = "create_time")
       private Date createTime ;  
       // 部门id
       @ManyToOne
       @JoinColumn(name = "department_id")
       private Department department ;
   }
   @Entity@Data@NoArgsConstructor
   public class Department {
         
         
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Integer id ;
        @Column
        private String name ;
        @Column
        @OneToMany(mappedBy = "department")
        private Set<User> users = new HashSet<>() ;
    }
   

4. 编写DAO层代码

   public interface UserRepository extends JpaRepository<User, Integer> {
         
         
       List<User> findByName(String name) ;
   }
   

5. 编写Service层代码

   public interface UserService {
         
         
       Integer addUser(User user) ;
       List<User> findAll(Sort sort) ;
       List<User> getAllUser(int page, int size) ;
       List<User> findByName(String name) ;
   }
   @Slf4j
   @Service
   @Transactional
   public class UserServiceImpl implements UserService {
         
         
       @Autowired
       private UserRepository userRepository ;
       @Override
       public Integer addUser(User user) {
         
         
           userRepository.save(user) ;
           Integer id = user.getId();
           user.setName("1" + user.getName());
           userRepository.save(user) ;
           return id ;
       }
       @Override
       public List<User> findAll(Sort sort) {
         
         
           return userRepository.findAll(sort);
       }
       @Override
       public List<User> getAllUser(int page, int size) {
         
         
           PageRequest pageable = PageRequest.of(page, size) ;
           Page<User> pageObject = userRepository.findAll(pageable);
           int totalPages = pageObject.getTotalPages();
           long totalElements = pageObject.getTotalElements();
           log.info("totalPages :{}", totalPages);
           log.info("totalElements : {}", totalElements);
           return pageObject.getContent();
       }
       @Override
       public List<User> findByName(String name) {
         
         
           return userRepository.findByName(name);
       }
   }
   

6. 编写单元测试

   @Slf4j
   @RunWith(SpringRunner.class)
   @SpringBootTest(classes = JpaBasicApiApplication.class)
   public class UserServiceTest {
         
         
       @Autowired
       private UserService userService ;
       @Test
       public void addUser(){
         
         
           User user = new User() ;
           user.setName("yicj");
           user.setCreateTime(new Date());
           userService.addUser(user) ;
       }
       @Test
       public void findAll(){
         
         
           Sort sort = Sort.by("id") ;
           List<User> users = userService.findAll(sort);
           log.info("users : {}", users);
       }
       @Test
       public void getAllUser(){
         
         
           int page = 1 ;
           int size = 10;
           List<User> allUser = userService.getAllUser(page, size);
           log.info("all users : {}", allUser);
       }
       @Test
       public void findByName(){
         
         
           String name = "yicj" ;
           List<User> list = userService.findByName(name);
           log.info("list : {}", list);
       }
   }