Spring中ResponseBodyAdvice的使用详解

public interface ResponseBodyAdvice<T> {

	
	boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType);

	
	@Nullable
	T beforeBodyWrite(@Nullable T body, MethodParameter returnType, MediaType selectedContentType,
			Class<? extends HttpMessageConverter<?>> selectedConverterType,
			ServerHttpRequest request, ServerHttpResponse response);

}

@ControllerAdvice
public class BaseResponseBodyAdvice implements ResponseBodyAdvice<Object> {


    @Override
    public boolean supports(MethodParameter returnType, Class converterType) {
        return true;
    }

    @Override
    public Object beforeBodyWrite(Object body, MethodParameter returnType,
            MediaType selectedContentType, Class selectedConverterType, ServerHttpRequest request,
            ServerHttpResponse response) {

        // 遇到feign接口之类的请求, 不应该再次包装,应该直接返回
        // 上述问题的解决方案: 可以在feign拦截器中,给feign请求头中添加一个标识字段, 表示是feign请求
        // 在此处拦截到feign标识字段, 则直接放行 返回body.

        System.out.println("响应拦截成功");

        if (body instanceof BaseResponse) {
            return body;
        } else if (body == null) {
            return BaseResponse.ok();
        } else {
            return BaseResponse.ok(body);
        }
    }
}

@Data
@AllArgsConstructor
@NoArgsConstructor
public class BaseResponse<T> {

    private T data;
    private int status = 200;
    private String message;
    private long srvTime = System.currentTimeMillis();

    public BaseResponse(String message) {
        this.message = message;
    }

    public BaseResponse<T> setData(T data) {
        this.data = data;
        return this;
    }

    public static <T> BaseResponse<T> ok() {
        return new BaseResponse<>("操作成功");
    }

    public static <T> BaseResponse<T> ok(T data) {
        return new BaseResponse<T>("操作成功").setData(data);
    }

}

@Controller
@RequestMapping("/hello")
public class HelloWorld {

    // 此处数据从数据库中查询, 案例中也可以使用伪数据代替
    @Autowired
    private UserMapper userMapper;

    // {@code ResponseEntity} 案列
    @GetMapping("/one")
    @ResponseBody
    public User one() {

        List<User> users = userMapper.selectAll();
        System.out.println(users.get(0));
        return users.get(0);
    }

    
    // {@code @ResponseBody}  案列
    @GetMapping("/list")
    @ResponseBody
    public List<User> list() {

        List<User> users = userMapper.selectAll();
        System.out.println(users);
        return users;
    }
}    

User(id=1, username=李子柒, phone=77777, icon=李子柒的头像, queryTime=Wed Oct 27 20:47:02 CST 2021)
响应拦截成功

[User(id=1, username=李子柒, phone=77777, icon=李子柒的头像, queryTime=Wed Oct 27 20:46:58 CST 2021)]
响应拦截成功