mf-yuan

### SpringMvc中全局设置了`JSONWriter.Feature.WriteMapNullValue`，不过滤`NULL`值， 如何针对某个类型过滤NULL值，`JSONWriter.Feature`中是否存在过滤NULL的值 ```java @Bean public FastJsonHttpMessageConverter fastJsonHttpMessageConverter(){ FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter(); //自定义配置 FastJsonConfig config = new FastJsonConfig(); config.setDateFormat("yyyy-MM-dd HH:mm:ss"); config.setReaderFeatures(JSONReader.Feature.FieldBased, JSONReader.Feature.SupportArrayToBean); config.setWriterFeatures(JSONWriter.Feature.WriteMapNullValue); converter.setFastJsonConfig(config); converter.setDefaultCharset(StandardCharsets.UTF_8); converter.setSupportedMediaTypes(Collections.singletonList(MediaType.APPLICATION_JSON)); return converter; }...