自定义参数解析器HandlerMethodArgumentRes
2020-06-10 本文已影响0人
chanyi
1、解决的问题
加了@ResponseBody注解的方法,请求的方式是post的json格式,但如果我们也要通过post的application/x-www-form-urlencoded格式访问此接口。在不改变此接口的情况下。通过修改参数解析器HandlerMethodArgumentResovler来兼容两种请求方法。
2、思路
根据不同的content-type使用不同参数解析处理器。
Content-Type为application/x-www-form-urlencoded,使用ServletModelAttributeMethodProcessor解析器
Content-Type非application/x-www-form-urlencoded,使用RequestResponseBodyMethodProcessor解析器
3、代码实现
定义自己的参数解析器,继承HandlerMethodArgumentResolver
/**
* 自定义参数解析器
* 功能:实现不同类型参数的解析
* 使用@RequestBody注解,Content-Type为application/x-www-form-urlencoded,使用ServletModelAttributeMethodProcessor解析器
* 使用@RequestBody注解,Content-Type非application/x-www-form-urlencoded,使用RequestResponseBodyMethodProcessor解析器
*
* @author lilei
* @since 2020/05/09
*/
@Log4j
public class CustomMethodArgumentResolver implements HandlerMethodArgumentResolver {
private RequestResponseBodyMethodProcessor requestResponseBodyMethodProcessor;
private ServletModelAttributeMethodProcessor servletModelAttributeMethodProcessor;
private final String APPLICATION_X_WWW_FORM_URLENCODED = "application/x-www-form-urlencoded";
private final String MULTIPART_FORM_DATA = "multipart/form-data";
public CustomMethodArgumentResolver(
RequestResponseBodyMethodProcessor requestResponseBodyMethodProcessor,
ServletModelAttributeMethodProcessor servletModelAttributeMethodProcessor) {
this.requestResponseBodyMethodProcessor = requestResponseBodyMethodProcessor;
this.servletModelAttributeMethodProcessor = servletModelAttributeMethodProcessor;
}
/**
* 参数解析器适用参数条件
*
* @param methodParameter
* @return 使用@RequestBody注解 返回true,未使用返回false
* @tips 可以使用自定义注解
*/
@Override
public boolean supportsParameter(MethodParameter methodParameter) {
return methodParameter.hasParameterAnnotation(RequestBody.class);
}
/**
* 参数解析
* @param methodParameter
* @param modelAndViewContainer
* @param nativeWebRequest
* @param webDataBinderFactory
* @return
* @throws Exception
*/
@Override
public Object resolveArgument(MethodParameter methodParameter, ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest, WebDataBinderFactory webDataBinderFactory) throws Exception {
HttpServletRequest request = nativeWebRequest.getNativeRequest(HttpServletRequest.class);
if (request == null) {
throw new CustomrException(JsonResultCode.CODE_REQUEST_NULL.getName());
}
String contentType = request.getContentType();
//更加请求contentType不同使用不同解析器
log.info("contentType:"+contentType);
if (contentType.contains(APPLICATION_X_WWW_FORM_URLENCODED)||contentType.contains(MULTIPART_FORM_DATA)) {
log.info("Processor:"+servletModelAttributeMethodProcessor);
return servletModelAttributeMethodProcessor.resolveArgument(methodParameter, modelAndViewContainer, nativeWebRequest, webDataBinderFactory);
}
log.info("Processor:"+requestResponseBodyMethodProcessor);
return requestResponseBodyMethodProcessor.resolveArgument(methodParameter, modelAndViewContainer, nativeWebRequest, webDataBinderFactory);
}
}
注册参数解析器
/**
* 配置注册参数解析器
*/
@Configuration
@Log4j
public class ResolverConfig {
private final RequestMappingHandlerAdapter requestMappingHandlerAdapter;
public ResolverConfig(RequestMappingHandlerAdapter requestMappingHandlerAdapter) {
this.requestMappingHandlerAdapter = requestMappingHandlerAdapter;
}
@PostConstruct
private void addArgumentResolvers() {
log.info("start add argument resolvers...");
// 获取到的是不可变的集合
List<HandlerMethodArgumentResolver> argumentResolvers = requestMappingHandlerAdapter.getArgumentResolvers();
CustomMethodArgumentResolver customMethodArgumentResolver = getCustomMethodArgumentResolver(argumentResolvers);
//新建参数解析器列表,然后将新列表添加到requestMappingHandlerAdapter中
List<HandlerMethodArgumentResolver> newArgumentResolverList = new ArrayList<>(argumentResolvers.size() + 1);
// 将自定义方法参数解析器放置在第一个,并保留原来的解析器
newArgumentResolverList.add(customMethodArgumentResolver );
newArgumentResolverList.addAll(argumentResolvers);
requestMappingHandlerAdapter.setArgumentResolvers(newArgumentResolverList);
log.info("add argument resolvers end!!!");
}
/**
* 获取自定义方法参数解析器
* @param argumentResolversList
* @return
*/
private CustomMethodArgumentResolver getCustomMethodArgumentResolver(List<HandlerMethodArgumentResolver> argumentResolversList) {
// 解析Content-Type为application/json的默认解析器
RequestResponseBodyMethodProcessor requestResponseBodyMethodProcessor = null;
// 解析Content-Type为application/x-www-form-urlencoded的默认解析器
ServletModelAttributeMethodProcessor servletModelAttributeMethodProcessor = null;
if (argumentResolversList == null) {
throw new CustomResolverException(JsonResultCode.CODE_RESOLVER_NULL.getName(),JsonResultCode.CODE_RESOLVER_NULL.getCode());
}
for (HandlerMethodArgumentResolver argumentResolver : argumentResolversList) {
if (requestResponseBodyMethodProcessor != null && servletModelAttributeMethodProcessor != null) {
break;
}
if (argumentResolver instanceof RequestResponseBodyMethodProcessor) {
requestResponseBodyMethodProcessor = (RequestResponseBodyMethodProcessor) argumentResolver;
continue;
}
if (argumentResolver instanceof ServletModelAttributeMethodProcessor) {
servletModelAttributeMethodProcessor = (ServletModelAttributeMethodProcessor) argumentResolver;
}
}
if (requestResponseBodyMethodProcessor == null || servletModelAttributeMethodProcessor == null) {
throw new CustomResolverException(JsonResultCode.CODE_RESOLVER_VALUE_NULL.getName(),JsonResultCode.CODE_RESOLVER_VALUE_NULL.getCode());
}
return new CustomMethodArgumentResolver(requestResponseBodyMethodProcessor, servletModelAttributeMethodProcessor);
}
}