java - jackson JsonView 未被应用

Question

jackson 2.2.2

ObjectMapper mapper = new ObjectMapper();
mapper.getSerializationConfig().withView(Views.Public.class);
mapper.configure(MapperFeature.DEFAULT_VIEW_INCLUSION, false);
// if I try to simply configure using .without that config feature doesn't get set.
// I MUST use the .configure as above, but I guess that's a different question.
//        .without(MapperFeature.DEFAULT_VIEW_INCLUSION);

// this first one doesn't have the view applied.
String result = mapper.writeValueAsString(savedD);

// this second one works.
result = mapper.writerWithView(Views.Public.class).writeValueAsString(savedD);

如果我在 SerializationConfig 上设置 View ，我希望此配置应用于使用此 ObjectMapper 映射的所有对象。

如何使 ObjectMapper 始终应用 JsonView 而无需调用 writerWithView，以便我可以将此 ObjectMapper 提供给 Spring MVC？

Answer 1

事实证明，如果您真正阅读了文档，您会发现您不能仅通过调用 getSerializationConfig 并在其上调用 setter 来更改序列化配置。

/**
 * Method that returns the shared default {@link SerializationConfig}
 * object that defines configuration settings for serialization.
 *<p>
 * Note that since instances are immutable, you can NOT change settings
 * by accessing an instance and calling methods: this will simply create
 * new instance of config object.
 */
SerializationConfig getSerializationConfig();

我再说一遍，您不能通过访问实例和调用方法来更改设置:

所以你必须调用.configure方法而不是.without并且你不能通过调用.withView来设置 View 。这些方法将构造一个新的 SerializationConfig 实例，但无法将新的 SerializationConfig 返回到 ObjectMapper。

为了解决这个问题并连接我的 ObjectMapper 以供 Spring MVC 在处理 @ResponseBody 时使用，我实现了以下内容:

  @Configuration
  class WebConfig extends WebMvcConfigurerAdapter {
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
      MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
      ObjectMapper mapper = new ObjectMapper() {
        private static final long serialVersionUID = 1L;
        @Override
        protected DefaultSerializerProvider _serializerProvider(SerializationConfig config) {
          // replace the configuration with my modified configuration.
          // calling "withView" should keep previous config and just add my changes.
          return super._serializerProvider(config.withView(Views.Public.class));
        }        
      };
      mapper.configure(MapperFeature.DEFAULT_VIEW_INCLUSION, false);
      converter.setObjectMapper(mapper);
      converters.add(converter);
    }
  }

有了所有这些，一切都对我有用。