HandlerMethodArgumentResolver 自定义封装参数bean

小生最近写代码遇到一个小问题，一个controller有8个api，不过有7个api依赖登录api记录的session。如果session存在，则需要从session中获取clientId和password，否则退出到登录页面。

最开始我是在BaseController 中定义了一个公用的设置clientId和password的方法，后来发现这样很不优雅。于是想到了拦截器，但是拦截器针对每个方法都会调用，而且定位待处理的参数也不方便。最后我想到

HandlerMethodArgumentResolver 加注解的方式。下面贴出代码片段。

@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface BrokerRequestArgument {
}

public class BrokerRequestResolver implements HandlerMethodArgumentResolver {

    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        return parameter.getParameterAnnotation(BrokerRequestArgument.class) != null;
    }

    @Override
    public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
        String token = webRequest.getHeader("X-token");
        LoginUserModel loginUserModel = (LoginUserModel) webRequest.getAttribute(token, RequestAttributes.SCOPE_SESSION);

        Object obj = BeanUtils.instantiate(parameter.getParameterType());
        BeanWrapper wrapper = PropertyAccessorFactory
                .forBeanPropertyAccess(obj);
        Field[] fields = parameter.getParameterType().getDeclaredFields();
        Map<String, Field> fieldMap = Maps.newHashMap();
        for (Field field : fields) {
            fieldMap.put(field.getName(), field);
        }

        for (Iterator<String> paramNames = webRequest.getParameterNames(); paramNames.hasNext(); ) {
            String paramName = paramNames.next();
            Object o = webRequest.getParameter(paramName) ;
            wrapper.setPropertyValue(paramName,o);
        }
        wrapper.setPropertyValue("clientId",loginUserModel.getClientId());
        wrapper.setPropertyValue("password",loginUserModel.getPassword());
        return obj;
    }
}

<mvc:annotation-driven>
        <mvc:argument-resolvers>
            <bean class="
cn.xxx.xxx.web.resolver.BrokerRequestResolver" lazy-init="false"/>
        </mvc:argument-resolvers>
 </mvc:annotation-driven>

@RequestMapping(value = "/his_trade_entrusts", method = RequestMethod.GET)
    @ResponseBody
    public String hisEntrustQry(HttpServletRequest request, PagingQueryRequest brokerRequest) {
        setClientIdAndPassword(request,brokerRequest);
        BrokerResponse brokerResponse = guojinTradeService.hisEntrustQry(brokerRequest);
        return pagingResponse(brokerResponse);
    }

//变成了

@RequestMapping(value = "/his_trade_entrusts", method = RequestMethod.GET)
    @ResponseBody
    public String hisEntrustQry( @BrokerRequestArgument PagingQueryRequest brokerRequest) {
        BrokerResponse brokerResponse = guojinTradeService.hisEntrustQry(brokerRequest);
        return pagingResponse(brokerResponse);
    }

这样代码就优雅多了！

HandlerMethodArgumentResolver 自定义封装参数bean

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