如何避免HashMap中的空值序列化？
我想通过 Jackson JSON 处理器将 HashMap 序列化为字符串。 例如：
String strMap = getMapper().writeValueAsString(myHashMap);
result output -> {"r_id":6,"a_am":null,"smb":"Submit","a_li":null,"l_id":878,"pos":[1345,1346,1347]}
我不知道如何禁用 Map 的空值序列化。如果像这样配置 Jackson，则仅适用于 POJO：
mapper.getSerializationConfig().setSerializationInclusion(Inclusion.NON_NULL);
I would like to serialize a HashMap as a string through the Jackson JSON processor.
For example:
String strMap = getMapper().writeValueAsString(myHashMap);
result output -> {"r_id":6,"a_am":null,"smb":"Submit","a_li":null,"l_id":878,"pos":[1345,1346,1347]}
I don't know how to disable null values serialization for Map. It works fine only for POJO if configure the Jackson like this:
mapper.getSerializationConfig().setSerializationInclusion(Inclusion.NON_NULL);
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无论如何，Jackson 1.6 都会有这样的功能：
它确实可以满足您的需求。现有方法仅适用于 bean，并且不会进行更改以确保最大的向后兼容性。
编辑：根据评论的注释，这是针对 Jackson 1.x 的； Jackson 2.x 有匹配的
SerializationFeatureFor what it's worth, Jackson 1.6 will have this:
which does do what you want. Existing method only works for beans, and is not being changed to ensure maximum backwards compatibility.
EDIT: as per note on comments, this is for Jackson 1.x; Jackson 2.x has matching
SerializationFeature这是忽略 NULL 字段的最新注释
@JsonSerialize(include= JsonSerialize.Inclusion.NON_NULL)
Here is the latest annotation for ignoring the NULL fields
@JsonSerialize(include= JsonSerialize.Inclusion.NON_NULL)
使用 Jackson 2.1.2 我发现我可以用以下方式注释该类
@JsonInclude(Ininclude.NON_NULL)以便 null 根本不会被序列化。Using Jackson 2.1.2 I have found that I can annotate the class with
@JsonInclude(Include.NON_NULL)so that nulls are not serialized at all.或者您可以使用 @JsonWriteNullProperties(false) 注释您的 bean，这将
Or you can annotate your bean with @JsonWriteNullProperties(false) which will
使用最新的 Jackson 版本，在 ObjectMapper 上，您可以执行以下操作：
mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
With latest Jackson version, on the ObjectMapper, you can do:
mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);