Spring Boot 常用注解详解与使用最佳实践建议

@SpringBootApplication
public class MyApplication {
    public static void main(String[] args) {
        SpringApplication.run(MyApplication.class, args);
    }
}

@Configuration
public class AppConfig {
    @Bean
    public MyService myService() {
        return new MyServiceImpl();
    }
}

@SpringBootApplication
@ComponentScan({"com.example.main", "com.example.controllers"})
public class MyApplication {
    // ...
}

@Configuration
public class AppConfig {
    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

@Service
public class UserServiceImpl implements UserService {
    // 业务逻辑
}
@Repository
public class UserRepositoryImpl implements UserRepository {
    // 数据访问逻辑
}

@ConfigurationProperties(prefix = "app")
public class AppProperties {
    private String name;
    private String version;
    // getters/setters
}

@Bean
@Scope("prototype")
public MyPrototypeBean myPrototypeBean() {
    return new MyPrototypeBean();
}

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

@Autowired
@Qualifier("primaryDataSource")
private DataSource dataSource;

3. @Value
作用：注入属性值
使用场景：注入简单配置值
示例：

@RestController
@RequestMapping("/api/users")
public class UserController {
    @GetMapping("/{id}")
    public User getUser(@PathVariable Long id) {
        // ...
    }
}

@PostMapping("/create")
public ResponseEntity<User> createUser(@RequestBody UserDto userDto) {
    // ...
}

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

@GetMapping("/search")
public List<User> searchUsers(@RequestParam String keyword) {
    // ...
}

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

@Service
public class UserService {
    @Transactional
    public void updateUser(User user) {
        // ...
    }
}

@SpringBootTest
class MyIntegrationTests {
    @Autowired
    private MyService myService;
    // 测试方法
}

@WebMvcTest(UserController.class)
class UserControllerTests {
    @Autowired
    private MockMvc mockMvc;
    // 测试方法
}

@Service
public class UserService {
    @Cacheable("users")
    public User getUser(Long id) {
        // 只有第一次会执行，后续从缓存获取
    }
}

@Component
public class MyScheduler {
    @Scheduled(fixedRate = 5000)
    public void doTask() {
        // 每5秒执行一次
    }
}

@Service
public class AsyncService {
    @Async
    public void asyncMethod() {
        // 异步执行
    }
}