spring cloud 学习(11) - 用fastson替换jackson及用gb2312码输出

前几天遇到一个需求，因为要兼容旧项目的编码格式，需要spring-cloud的rest接口，输出gb2312编码，本以为是一个很容易的事情，比如下面这样：

    @RequestMapping(method = RequestMethod.POST, value = "syncPaymentList",
            consumes = {"application/json; charset=gb2312"},
            produces = {"application/json; charset=gb2312"})
    public GatewayDataResult<DcbOrderListResponse> syncPaymentList(SyncPaymentListRequest request) {
        ...return ...;
    }

发现只是把输出的response里Content-Type变成了application/json;charset=gb2312，内容本身并没有变化（即：浏览器设置成简体中文，显示乱码）

有一个很简单粗暴的办法，到是可以(参考下面的)，但是对原来代码改变太大：

    @RequestMapping(method = RequestMethod.GET, value = "/test")
    public void gb2312Test(HttpServletResponse response) throws IOException {
        response.setContentType("application/json;charset=gb2312");
        PrintWriter out = response.getWriter();
        out.print("{\"errno\":12,\"errmsg\":\"登录超时\"}");
        return;
    }

另外网有一些办法，比如修改application.yml

spring:
  http:
    encoding:
      enabled: true
      charset: GB2312
      force: true　　

相当于传统spring-mvc中下面这段配置

    <filter>
        <filter-name>CharacterEncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>gb2312</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

发现也没用，然后看了下jackson2的源码，com.fasterxml.jackson.core.JsonEncoding这个类，默认就只支持UTF-8/16编码，要支持其它编码的话

得自己扩展JsonGenerator,写一堆代码，太复杂，参考：https://*.com/questions/10004241/jackson-objectmapper-with-utf-8-encoding

最后想起了以前dubbo中用fastjson替换jackson时，解决过类似问题（参考 dubbox REST服务使用fastjson替换jackson） ，发现了一个很简单的办法，拿fastjson替换jackson2，只要注入下面这个bean就可以了：

     @Bean
     public HttpMessageConverters fastJsonHttpMessageConverters() {
         FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
         FastJsonConfig fastJsonConfig = new FastJsonConfig();
         fastJsonConfig.setSerializerFeatures(SerializerFeature.DisableCircularReferenceDetect);
         fastJsonConfig.setCharset(Charset.forName("gb2312"));

         List<MediaType> fastMediaTypes = new ArrayList<>();
         fastMediaTypes.add(MediaType.APPLICATION_JSON);
         fastConverter.setSupportedMediaTypes(fastMediaTypes);

         fastConverter.setFastJsonConfig(fastJsonConfig);
         HttpMessageConverter<?> converter = fastConverter;
         return new HttpMessageConverters(converter);
     }