Spring MVC ResponseBodyAdvice 用于在指定 return 类型中添加 header

Question

我的控制器中有一个方法 return object 列表。该方法支持分页结果，在HttpHeader中添加HttpHeaders.LINK以支持Pagination Discoverability。我被迫添加此行以支持 . 我认为也许 ControllerAdvice 或 ResponseAdvice 支持在那做这件事。我如何检查 return 方法？如果 return 类型是 QueryResult 则向其添加 HttpHeader?

@RequestMapping(value = "/list", method = RequestMethod.GET)
    public ResponseEntity<QueryResult<Personel>> search(
            SearchOption searchOption)  {
        QueryResult<Personel> list=ipersonelService.search();
        HttpHeaders headers = PaginationUtil.generatePaginationHttpHeaders(list, "/api/personel");
        return new ResponseEntity<>(list, headers, HttpStatus.OK);
    }

这个class通过分页生成Headersclass

public static HttpHeaders generatePaginationHttpHeaders(QueryResult page, String baseUrl)
    throws URISyntaxException {

    HttpHeaders headers = new HttpHeaders();
    headers.add("X-Total-Count", "" + page.getTotalElements());
    String link = "";
    if ((page.getPageNumber() + 1) < page.getTotalPages()) {
        link = "<" + generateUri(baseUrl, page.getPageNumber() + 1, page.getPageSize()) + ">; rel=\"next\",";
    }
    // prev link
    if ((page.getPageNumber()) > 0) {
        link += "<" + generateUri(baseUrl, page.getPageNumber() - 1, page.getPageSize()) + ">; rel=\"prev\",";
    }
    // last and first link
    int lastPage = 0;
    if (page.getTotalPages() > 0) {
        lastPage = page.getTotalPages() - 1;
    }
    link += "<" + generateUri(baseUrl, lastPage, page.getPageSize()) + ">; rel=\"last\",";
    link += "<" + generateUri(baseUrl, 0, page.getPageSize()) + ">; rel=\"first\"";
    headers.add(HttpHeaders.LINK, link);
    return headers;
}


private static String generateUri(String baseUrl, int page, int size) throws URISyntaxException {
        return UriComponentsBuilder.fromUriString(baseUrl).queryParam("page", page).queryParam("size", size).toUriString();
    }



public class QueryResult<T> {

    private int     pageNumber;
    private int     totalElements;
    private int     totalPages;
    private int     pageSize;

    @JsonProperty("rows")
    private List<T> items;

    public QueryResult() {

    }   

    public int getPageNumber() {
        return pageNumber;
    }

    public void setPageNumber(int pageNumber) {
        this.pageNumber = pageNumber;
    }

    public int getTotalElements() {
        return totalElements;
    }

    public void setTotalElements(int totalElements) {
        this.totalElements = totalElements;
    }

    public int getPageSize() {
        return pageSize;
    }

    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }

    public List<T> getItems() {
        return items;
    }

    public void setItems(List<T> items) {
        this.items = items;
    }

    public int getTotalPages() {
        if (this.getPageSize() > 0)
            return this.getTotalElements() / this.getPageSize();

        return 0;
    }

    public void setTotalPages(int totalPages) {
        this.totalPages = totalPages;
    }

}

我想写这样的方法并自动添加link headers

@RequestMapping(value = "/list", method = RequestMethod.GET)
        public QueryResult<Personel> search(
                SearchOption searchOption)  {
            return ripersonelService.search();
        }

经过搜索我找到了这个解决方案

@ControllerAdvice
public class BaseController implements ResponseBodyAdvice<Object> {


    private final Logger logger = Logger.getLogger(BaseController.class);

    @Override
    public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
        return true;
    }

    @Override
    public Object beforeBodyWrite(
            Object body,
            MethodParameter returnType,
            MediaType selectedContentType,
            Class<? extends HttpMessageConverter<?>> selectedConverterType,
            ServerHttpRequest request,
            ServerHttpResponse response)  {
        if(body instanceof QueryResult){
            QueryResult result =(QueryResult) body;
            HttpHeaders headers = PaginationUtil.generatePaginationHttpHeaders(result, request.getURI().getPath());
            response.getHeaders().add(HttpHeaders.LINK, headers.getFirst(HttpHeaders.LINK));
            response.getHeaders().add("X-Total-Count", headers.getFirst("X-Total-Count"));
        }

        return body;
    }
}

Answer 1

您可以使用 ResponseBodyAdvice (typically also annotated with @ControllerAdvice). Your implementation's beforeBodyWrite method will be called with the response body and the ServerHttpResponse 的实现。后者使您可以访问响应 headers 并允许您根据需要更新它们。

Spring MVC ResponseBodyAdvice 用于在指定 return 类型中添加 header

Spring MVC ResponseBodyAdvice for add header in specify return type

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