Spring Data的代码实例

下面是一个简单的 Spring Data 的代码实例，使用了 Spring Data JPA 和 Hibernate。

1. 定义实体类

@Entity
@Table(name = "user")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column(name = "name")
    private String name;

    @Column(name = "age")
    private Integer age;

    // getter、setter、构造函数等省略
}

2. 创建 Repository 接口

public interface UserRepository extends JpaRepository<User, Long> {

    List<User> findByName(String name);

}

3. 编写 Service 类

@Service
public class UserService {

    @Autowired
    private UserRepository userRepository;

    public List<User> findByName(String name) {
        return userRepository.findByName(name);
    }

    public User save(User user) {
        return userRepository.save(user);
    }

    public void delete(Long id) {
        userRepository.deleteById(id);
    }

}

4. 使用 Service 类

@RestController
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping("/users")
    public List<User> getUsers(@RequestParam(required = false) String name) {
        if (name != null) {
            return userService.findByName(name);
        } else {
            return userService.findAll();
        }
    }

    @PostMapping("/users")
    public User createUser(@RequestBody User user) {
        return userService.save(user);
    }

    @DeleteMapping("/users/{id}")
    public void deleteUser(@PathVariable Long id) {
        userService.delete(id);
    }

}