一、Maven依赖

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>${fastjson.version}</version>
</dependency>

二、配置类

@Configuration
public class BeanConfig {
    /*注入Bean : HttpMessageConverters，以支持fastjson*/
    @Bean
    public HttpMessageConverters fastJsonHttpMessageConverters() {
        FastJsonHttpMessageConverter fastConvert = new FastJsonHttpMessageConverter();
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat,
                SerializerFeature.WriteNullStringAsEmpty,
                SerializerFeature.WriteNullNumberAsZero,
                SerializerFeature.WriteNullListAsEmpty,
                SerializerFeature.WriteMapNullValue,
                SerializerFeature.DisableCheckSpecialChar);
        fastJsonConfig.setDateFormat("yyyy-MM-dd hh:mm:ss");
        //处理中文乱码问题
        List<MediaType> fastMediaTypes = new ArrayList<>();
        fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
        fastConvert.setSupportedMediaTypes(fastMediaTypes);
        fastConvert.setFastJsonConfig(fastJsonConfig);
        return new HttpMessageConverters((HttpMessageConverter<?>) fastConvert);
    }
}
注：此方法会出现字符串双引号问题。

三、完美解决配置

@Configuration
@Slf4j
public class WebConfig implements WebMvcConfigurer {
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/statics/**").addResourceLocations("classpath:/statics/");
    }

    public HttpMessageConverter<String> stringConverter() {
        StringHttpMessageConverter converter = new StringHttpMessageConverter(
                Charset.forName("UTF-8"));
        return converter;
    }

    public HttpMessageConverter fastConverter() {
        //1、定义一个convert转换消息的对象
        FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
        //2、添加fastjson的配置信息
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat,
                SerializerFeature.WriteNullStringAsEmpty,   //字符串null返回空字符串
                SerializerFeature.WriteNullNumberAsZero,    //数值类型为0
                SerializerFeature.WriteNullListAsEmpty,     //空字段保留
                SerializerFeature.WriteMapNullValue);
        fastJsonConfig.setCharset(Charset.forName("UTF-8"));
        //2-1 处理中文乱码问题
        List<MediaType> fastMediaTypes = new ArrayList<>();
        fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
        fastConverter.setSupportedMediaTypes(fastMediaTypes);
        //3、在convert中添加配置信息
        fastConverter.setFastJsonConfig(fastJsonConfig);
        return fastConverter;
    }

    @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.clear();
        converters.add(stringConverter());
        converters.add(fastConverter());
    }

    @Bean
    public WebMvcConfigurer corsConfigurer() {
        return new WebMvcConfigurer() {
            @Override
            public void addCorsMappings(CorsRegistry registry) {
                registry.addMapping("/**").allowedOrigins("*").allowedMethods("*").allowCredentials(true);
            }
        };
    }
}
注：FastJsonHttpMessageConverter  前面必须有一个StringHttpMessageConverter

四、fastjson SerializerFeature说明

QuoteFieldNames 输出key时是否使用双引号,默认为true   
UseSingleQuotes 使用单引号而不是双引号,默认为false    
WriteMapNullValue   是否输出值为null的字段,默认为false  
WriteEnumUsingToString  Enum输出name()或者original,默认为false 
UseISO8601DateFormat    Date使用ISO8601格式输出，默认为false  
WriteNullListAsEmpty    List字段如果为null,输出为[],而非null  
WriteNullStringAsEmpty  字符类型字段如果为null,输出为”“,而非null  
WriteNullNumberAsZero   数值字段如果为null,输出为0,而非null 
WriteNullBooleanAsFalse Boolean字段如果为null,输出为false,而非null    
SkipTransientField  如果是true，类中的Get方法对应的Field是transient，序列化时将会被忽略。默认为true    
SortField   按字段名称排序后输出。默认为false 
WriteTabAsSpecial   把\t做转义输出，默认为false   不推荐
PrettyFormat    结果是否格式化,默认为false    
WriteClassName  序列化时写入类型信息，默认为false。反序列化是需用到    
DisableCircularReferenceDetect  消除对同一对象循环引用的问题，默认为false 
WriteSlashAsSpecial 对斜杠’/’进行转义  
BrowserCompatible   将中文都会序列化为\uXXXX格式，字节数会多一些，但是能兼容IE 6，默认为false    
WriteDateUseDateFormat  全局修改日期格式,默认为false。JSON.DEFFAULT_DATE_FORMAT = “yyyy-MM-dd”;JSON.toJSONString(obj, SerializerFeature.WriteDateUseDateFormat);    
DisableCheckSpecialChar 一个对象的字符串属性中如果有特殊字符如双引号，将会在转成json时带有反斜杠转移符。如果不需要转义，可以使用这个属性。默认为false 
NotWriteRootClassName   含义  
BeanToArray 将对象转为array输出    
WriteNonStringKeyAsString   含义  
NotWriteDefaultValue    含义  
BrowserSecure   含义  
IgnoreNonFieldGetter    含义  
WriteEnumUsingName  含义