java – 杰克逊JSON不包含嵌套对象的属性

我有以下课程：

public class Container {
    private String name;
    private Data data;
}

public class Data {
    private Long id;
}

当我使用杰克逊序列化容器类时,我得到

{"name":"Some name","data":{"id":1}}

但我需要的结果是：

{"name":"Some name","id":1}

是否可以(不添加Container.getDataId()方法)？如果是这样,怎么办？

更新

我试图创建自定义JsonSerializer< Data>但结果与以前相同

public class JsonDataSerializer extends JsonSerializer<Data> {

    private static Logger logger = Logger.getLogger(JsonDataSerializer.class);

    @Override
    public void serialize(Data value,JsonGenerator jgen,SerializerProvider provider)
            throws IOException,JsonProcessingException {

        Long id = (value.getId() == null) ? 0l : value.getId();
        jgen.writeStartObject();
        jgen.writeNumberField("id",id);
        jgen.writeEndobject();
        logger.debug("Data id " + id + " serialized to JSON.");       
    }
}

我还试图在Data类之上添加@JsonSerialize注释,然后在Container类中添加getter.如前所述,没有任何成功.我的串行器被使用,记录器日志消息.

更新2

当我删除writeStartObject()和writeEndobject(),然后没有JSON是returnesd,只有HTTP状态500错误,没有异常抛出,除了我在调试输出中找到.

DEBUG: org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerExceptionResolver - Resolving exception from handler [com.example.DataController@16be8a0]: org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Can not write a field name,expecting a value; nested exception is org.codehaus.jackson.JsonGenerationException: Can not write a field name,expecting a value
DEBUG: org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver - Resolving exception from handler [com.example.DataController@16be8a0]: org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Can not write a field name,expecting a value
DEBUG: org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver - Resolving exception from handler [com.example.DataController@16be8a0]: org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Can not write a field name,expecting a value

解决方法

杰克逊1.9已经引入了 JsonUnwrapped注释,它是你正在寻找的.