SpringArgumentResolver獲取路徑變數映射和

這是我的方法簽名

@RequestMapping(value = {"/article", "/article/{id}", "/article/{name}"}, method = RequestMethod.GET,
                consumes = MediaType.APPLICATION_JSON_UTF8_VALUE, produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
 
  public ResponseEntity<JsonNode> get(@PathVariable Map<String, String> pathVarsMap, @RequestParam(value="test") MultiValueMap<String, String> test, @RequestBody(required=false) JsonNode requestBody )

我想把它變成

public ResponseEntity<JsonNode> get( MyStructure mystr)

里面MyStructure 會有@PathVariable Map<String, String> pathVarsMap, @RequestParam(value="test") MultiValueMap<String, String> test, @RequestBody(required=false) JsonNode requestBody什么。

我知道我必須使用自定義決議器并實施resolveArgument. 我看到的一個例子就是這樣做的(Map<String, String>) httpServletRequest.getAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE)。但我不知道如何讓它作業。我可以在 MyString 中創建MultiValueMap和內部嗎？RequestBody

在另一個地方，我看到建議是使用

@Nonnull
protected final Map<String, String>   getUriTemplateVariables(NativeWebRequest request) {
@SuppressWarnings("unchecked")
Map<String, String> variables =
        (Map<String, String>) request.getAttribute(
                URI_TEMPLATE_VARIABLES_ATTRIBUTE, SCOPE_REQUEST);
return (variables != null) ? variables : Collections.<String, String>emptyMap();
}

所以我對我應該如何實作這個有點困惑

uj5u.com熱心網友回復：

all @PathVariable, @RequestParamand@RequestBody只能在方法引數上注解，所以沒有辦法在物件欄位上注解。

決議這些注釋值的現有代碼HandlerMethodArgumentResolver也假定這些注釋在方法引數上進行了注釋，這意味著您也不能簡單地委托給它們來決議您的請求物件的值。

您最好的選擇是簡單地參考HandlerMethodArgumentResolver每個注釋的對應代碼并將相關代碼復制到您的實作中。

• 對于@PathVariable，它是由PathVariableMapMethodArgumentResolver
• 對于@RequestParamon MultiValueMap，它通過以下方式解決RequestParamMapMethodArgumentResolver
• 因為@RequestBody，它是由 解決的RequestResponseBodyMethodProcessor。在內部，它使用一個串列HttpMessageConverter來讀取 HTTP 請求正文。由于您現在使用 Jackson 來讀取請求正文，因此您只需要專注于MappingJackson2HttpMessageConverter簡單起見。

這比我預期的要容易。以下實作對您來說應該是一個很好的起點。

首先定義MyStructure類：

public class MyStructure {
    public Map<String, String> pathVariables;
    public MultiValueMap<String, String> queryParameters;
    public JsonNode requestBody;
}

并實施MyStructureArgumentResolver：

public class MyStructureArgumentResolver implements HandlerMethodArgumentResolver {

        private MappingJackson2HttpMessageConverter messageConverter;

        public MyStructureArgumentResolver(MappingJackson2HttpMessageConverter messageConverter) {
            super();
            this.messageConverter = messageConverter;
        }

        @Override
        public boolean supportsParameter(MethodParameter parameter) {
            return MyStructure.class.isAssignableFrom(parameter.getParameterType());
        }

        @Override
        public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,
                NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {

            MyStructure request = new MyStructure();

            request.queryParameters = resolveQueryParameters(webRequest);
            request.pathVariables = resolvePathVariables(webRequest);
            request.requestBody = resolveRequestBody(webRequest, parameter);

            return request;
        }

        private MultiValueMap<String, String> resolveQueryParameters(NativeWebRequest webRequest) {
            // resolve all query parameter into MultiValueMap
            Map<String, String[]> parameterMap = webRequest.getParameterMap();
            MultiValueMap<String, String> result = new LinkedMultiValueMap<>(parameterMap.size());
            parameterMap.forEach((key, values) -> {
                for (String value : values) {
                    result.add(key, value);
                }
            });
            return result;
        }

        private Map<String, String> resolvePathVariables(NativeWebRequest webRequest) {
            Map<String, String> uriTemplateVars = (Map<String, String>) webRequest.getAttribute(
                    HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE, RequestAttributes.SCOPE_REQUEST);

            if (!CollectionUtils.isEmpty(uriTemplateVars)) {
                return new LinkedHashMap<>(uriTemplateVars);
            } else {
                return Collections.emptyMap();
            }
        }

        private JsonNode resolveRequestBody(NativeWebRequest webRequest, MethodParameter parameter)
                throws IOException, HttpMediaTypeNotSupportedException, HttpMessageNotReadableException {

            HttpServletRequest servletRequest = webRequest.getNativeRequest(HttpServletRequest.class);
            HttpInputMessage inputMessage = new ServletServerHttpRequest(servletRequest);

            MediaType contentType;
            try {
                contentType = inputMessage.getHeaders().getContentType();
            } catch (InvalidMediaTypeException ex) {
                throw new HttpMediaTypeNotSupportedException(ex.getMessage());
            }
            if (contentType == null) {
                contentType = MediaType.APPLICATION_OCTET_STREAM;
            }
            Class<?> contextClass = parameter.getContainingClass();

            JsonNode body = JsonNodeFactory.instance.objectNode();

            if (messageConverter.canRead(JsonNode.class, contextClass, contentType)) {
                body = (JsonNode) messageConverter.read(JsonNode.class, inputMessage);
            }

            return body;
        }
    }

然后注冊MyStructureArgumentResolver：

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Autowired
    private MappingJackson2HttpMessageConverter messageConverter;

    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {
        resolvers.add(new MyStructureArgumentResolver(messageConverter));
    }
}

并在控制器方法中使用它：

@RequestMapping(value = { "/test/{name}" }, method = RequestMethod.GET)
public ResponseEntity<String> test(MyStructure request) {

}

uj5u.com熱心網友回復：

@PostMapping("/get")
public ResponseEntity<JsonNode> get( @RequestBody MyStructure mystr){...}

呼叫該介面時，在請求體中填寫引數，將body作為application/json發送。參考這個示例：示例專案

標籤：爪哇春天弹簧靴弹簧MVC注释

上一篇：如何在SpringBoot中獲取application.prpoperty的值

下一篇：Golang中結構型別之間的轉換