Spring Boot 完整 REST CRUD 示例

使用Spring Boot可以快速开发RESTful API，并实现完整的CRUD操作。本文将通过一个示例来演示如何使用Spring Boot构建一个完整的RESTful API，并对每个操作进行详细的解释。

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

java
@Repository
public interface UserRepository extends JpaRepository {
}

java
@Service
public class UserService {
    @Autowired
    private UserRepository userRepository;
    public User createUser(User user) {
        return userRepository.save(user);
    }
    public List getUsers() {
        return userRepository.findAll();
    }
    public User getUserById(Long id) {
        Optional optionalUser = userRepository.findById(id);
        return optionalUser.orElse(null);
    }
    public User updateUser(User user) {
        return userRepository.save(user);
    }
    public void deleteUser(Long id) {
        userRepository.deleteById(id);
    }
}

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