引入FastJsonHttpMessageConverter需要注意的地方

@Configuration
 public class WebSecurityConfig extends WebMvcConfigurerAdapter {
 
     FastJsonHttpMessageConverter fastJsonHttpMessageConverter(){
        FastJsonHttpMessageConverter fastJsonHttpMessageConverter=new FastJsonHttpMessageConverter();
       FastJsonConfig fastJsonConfig=new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(
                SerializerFeature.QuoteFieldNames,
                SerializerFeature.WriteMapNullValue,
                SerializerFeature.DisableCircularReferenceDetect,
                SerializerFeature.WriteDateUseDateFormat,
                SerializerFeature.WriteNullStringAsEmpty);
       List<MediaType> mediaTypeList=new ArrayList<>();
        mediaTypeList.add(MediaType.APPLICATION_JSON_UTF8);
        mediaTypeList.add(MediaType.APPLICATION_JSON);
        fastJsonHttpMessageConverter.setSupportedMediaTypes(mediaTypeList);
        fastJsonHttpMessageConverter.setFastJsonConfig(fastJsonConfig);
        return fastJsonHttpMessageConverter;
     }
 
 
//保证StringHttpMessageConverter在FastJsonHttpMessageConverter前被调用
 @Override
     public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
         //converters.removeIf(t -> t instanceof MappingJackson2HttpMessageConverter);
         converters.clear();
         StringHttpMessageConverter converter = new StringHttpMessageConverter(
                 Charset.forName("UTF-8"));
         converters.add(converter);        
         converters.add(fastJsonHttpMessageConverter());
     }