<dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.34</version>
        </dependency>

    @Bean
    public HttpMessageConverters fastJsonHttpMessageConverters() {
        FastJsonHttpMessageConverter4 fastConverter = new FastJsonHttpMessageConverter4();
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat, SerializerFeature.WriteMapNullValue);
        fastConverter.setFastJsonConfig(fastJsonConfig);
        fastConverter.setSupportedMediaTypes(Arrays.asList(MediaType.APPLICATION_JSON_UTF8, MediaType.parseMediaType("text/html;charset=UTF-8")));
        return new HttpMessageConverters(fastConverter);
    }