springboot简单增删改查代码

以下是一个简单的基于Spring Boot的增删改查代码示例：

1. 创建实体类

@Entity
@Table(name = "users")
public class User {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    
    private String name;
    
    private String email;
    
    // getters and setters
}

2. 创建数据访问接口

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

3. 创建服务类

@Service
public class UserService {
    
    @Autowired
    private UserRepository userRepository;
    
    public List<User> getAllUsers() {
        return userRepository.findAll();
    }
    
    public User getUserById(Long id) {
        return userRepository.findById(id).orElse(null);
    }
    
    public User addUser(User user) {
        return userRepository.save(user);
    }
    
    public User updateUser(Long id, User user) {
        User existingUser = userRepository.findById(id).orElse(null);
        if (existingUser != null) {
            existingUser.setName(user.getName());
            existingUser.setEmail(user.getEmail());
            userRepository.save(existingUser);
        }
        return existingUser;
    }
    
    public void deleteUser(Long id) {
        userRepository.deleteById(id);
    }
}

4. 创建控制器类

@RestController
@RequestMapping("/users")
public class UserController {
    
    @Autowired
    private UserService userService;
    
    @GetMapping("")
    public List<User> getAllUsers() {
        return userService.getAllUsers();
    }
    
    @GetMapping("/{id}")
    public User getUserById(@PathVariable Long id) {
        return userService.getUserById(id);
    }
    
    @PostMapping("")
    public User addUser(@RequestBody User user) {
        return userService.addUser(user);
    }
    
    @PutMapping("/{id}")
    public User updateUser(@PathVariable Long id, @RequestBody User user) {
        return userService.updateUser(id, user);
    }
    
    @DeleteMapping("/{id}")
    public void deleteUser(@PathVariable Long id) {
        userService.deleteUser(id);
    }
}

以上代码实现了一个简单的增删改查功能，你可以在控制器类的接口上添加相应的注解来限制访问权限。同时，你可以添加异常处理程序来处理异常情况。