杰克逊:仅序列化标记的字段

Question

我正在尝试做一些在gson中非常容易的事情.由于我切换到Jackson作为序列化器,我无法弄清楚如何实现这个:

我想仅序列化已由Annotation标记的字段.GSON代码将是:

class Foo {
    @Expose
    public String sometext="Hello World";
    @Expose
    public int somenumber=30;
    public float noop=1.0;
    ...
 }

应该导致(JSON)

 {
    Foo: {
        sometext:'Hello World',
        somenumber: 30
    }
 }

(语法错误可能会被忽略 - 源仅用于演示)

那么什么是杰克逊对口GSON的@Expose和new GsonBuilder().excludeFieldsWithoutExposeAnnotation().create();？

Answer 1

如果您只希望它用于特定类型，您也可以只使用注释：

@JsonAutoDetect(
    fieldVisibility = Visibility.NONE,
    setterVisibility = Visibility.NONE,
    getterVisibility = Visibility.NONE,
    isGetterVisibility = Visibility.NONE,
    creatorVisibility = Visibility.NONE
)
public class Foo  {
    @JsonProperty
    public String sometext="Hello World";
    @JsonProperty
    public int somenumber=30;
    // noop won't get serialized
    public float noop= 1.0f;
}

Answer 2

对应的new GsonBuilder().excludeFieldsWithoutExposeAnnotation().create();是初始化一个 ObjectMapper，如下所示：

...
ObjectMapper objectMapper = new ObjectMapper();        
objectMapper.disable(MapperFeature.AUTO_DETECT_CREATORS,
            MapperFeature.AUTO_DETECT_FIELDS,
            MapperFeature.AUTO_DETECT_GETTERS,
            MapperFeature.AUTO_DETECT_IS_GETTERS);
...

@Expose那么 的对应项是@JsonProperty。使用上面的示例 bean：

class Foo {
    @JsonProperty
    public String sometext="Hello World";
    @JsonProperty
    public int somenumber=30;
    public float noop=1.0;
    ...
 }

请参阅这个非常相似问题的答案。

Answer 3

似乎有一种方法可以配置ObjectMapper为忽略所有未注释的字段。

ObjectMapper mapper = new ObjectMapper();
mapper.setVisibilityChecker(getSerializationConfig().getDefaultVisibilityChecker()
.withCreatorVisibility(JsonAutoDetect.Visibility.NONE)
.withFieldVisibility(JsonAutoDetect.Visibility.NONE)
.withGetterVisibility(JsonAutoDetect.Visibility.NONE)
.withIsGetterVisibility(JsonAutoDetect.Visibility.NONE)
.withSetterVisibility(JsonAutoDetect.Visibility.NONE));

来源