SpringBoot项目实用功能之实现自定义参数解析器

org.springframework.web.method.support.HandlerMethodArgumentResolver

org.springframework.web.servlet.config.annotation.WebMvcConfigurer

org.springframework.web.method.support.HandlerMethodArgumentResolver

public class QueryParamArgumentResolver implements HandlerMethodArgumentResolver {
    /**
     * 判断当前参数是否需要解析，该解析器用来解析参数类型为List<QueryParam>
     *
     * @param parameter
     * @return
     */
    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        boolean isList = List.class.equals(parameter.getParameterType());
        if (isList) {
            Type genericType = parameter.getGenericParameterType();
            if (genericType instanceof ParameterizedType) {
                ParameterizedType parameterizedType = (ParameterizedType) genericType;
                Type actualTypeArgument = parameterizedType.getActualTypeArguments()[0];
                return actualTypeArgument.getTypeName().equals(QueryParam.class.getName());
            }
        }
        return false;
    }
    /**
     * 将前端参数名称为{@link ContextKey#queryParams}的字符串值解析为List<QueryParam>，用于查询
     *
     * @param parameter
     * @param mavContainer
     * @param webRequest
     * @param binderFactory
     * @return
     * @throws Exception
     */
    @Override
    public List<QueryParam> resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,
            NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
        String queryParamsStr = webRequest.getParameter(ContextKey.queryParams.name());
        if (StrUtil.isBlank(queryParamsStr)) {
            return Collections.emptyList();
        }
        final List<QueryParam> params = JsonUtil.getInstance()
                .readValue(queryParamsStr, new TypeReference<List<QueryParam>>() {
                    @Override
                    public Type getType() {
                        return super.getType();
                    }
                });
        if (CollectionUtil.isNotEmpty(params)) {
            for (QueryParam param : params) {
                if (param.getRelative() == null) {
                    param.setRelative(QueryParam.Relative.AND);
                }
                if (param.getOp() == null) {
                    param.setOp(QueryParam.Op.EQ);
                }
            }
        }
        return params;
    }
}

@Configuration
public class CoreWebConfig implements WebMvcConfigurer {
    /**
     * 注册解析器
     *
     * @return
     */
    @Bean
    public QueryParamArgumentResolver queryParamArgumentResolver() {
        return new QueryParamArgumentResolver();
    }
    
    /**
     * 配置自定义参数解析器
     *
     * @param resolvers
     */
    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {
        resolvers.add(queryParamArgumentResolver());
    }
}