springboot进行增删改查操作代码

下面是一个使用Spring Boot进行增删改查操作的示例代码：

1. 创建一个实体类

@Entity
@Table(name = "users")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;

    private Integer age;

    // 省略getter/setter方法
}

2. 创建一个repository

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

3. 创建一个service

@Service
public class UserService {
    @Autowired
    private UserRepository userRepository;

    public List<User> findAll() {
        return userRepository.findAll();
    }

    public User findById(Long id) {
        return userRepository.findById(id)
                .orElseThrow(() -> new NotFoundException("User not found with id " + id));
    }

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

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

    public User update(Long id, User updatedUser) {
        User user = userRepository.findById(id)
                .orElseThrow(() -> new NotFoundException("User not found with id " + id));

        user.setName(updatedUser.getName());
        user.setAge(updatedUser.getAge());

        return userRepository.save(user);
    }
}

4. 创建一个controller

@RestController
@RequestMapping("/users")
public class UserController {
    @Autowired
    private UserService userService;

    @GetMapping("")
    public List<User> findAll() {
        return userService.findAll();
    }

    @GetMapping("/{id}")
    public User findById(@PathVariable Long id) {
        return userService.findById(id);
    }

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

    @PutMapping("/{id}")
    public User update(@PathVariable Long id, @RequestBody User user) {
        return userService.update(id, user);
    }

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

这样就完成了一个简单的增删改查操作的代码示例。