how to configure spring mvc 3 to not return “null” object in json response?
转自：http://stackoverflow.com/questions/6049523/how-to-configure-spring-mvc-3-to-not-return-null-object-in-json-response
a sample of json response looks like this:
{"publicId":"123","status":null,"partner":null,"description":null}
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It would be nice to truncate out all null objects in the response. In this case, the response would become
{"publicId":"123"}.
Any advice? Thanks!
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1 Answer
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Yes, you can do this for individual classes by annotating them with @JsonSerialize(include=JsonSerialize.Inclusion.NON_NULL) or you can do it across the board by configuring your ObjectMapper, setting the serialization inclusion to JsonSerialize.Inclusion.NON_NULL.
Here is some info from the Jackson FAQ: http://wiki.fasterxml.com/JacksonAnnotationSerializeNulls.
Annotating the classes is straightforward, but configuring the ObjectMapper serialization config slightly trickier. There is some specific info on doing the latter here.
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Jackson feature: prevent serialization of nulls, default values
As of Jackson 1.1, you can suppress serialization of properties that have either:
- Null value, or
- Default value for the bean (which may be null, or any other value after being constructed using the default constructor)
These is achieved by using one of 2 mechanisms:
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Call ObjectMapper.getSerializationConfig().setSerializationInclusion() to define global setting (value enumeration JsonSerialize.Inclusion, with values ALWAYS, NON_NULL, NON_DEFAULT).
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Annotate properties (i.e. serializable field or getter method that implies a property) with @JsonSerialize(include=VALUE), where value is as above.
So either:
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ObjectMapper mapper = new ObjectMapper();
mapper.getSerializationConfig().setSerializationInclusion(JsonSerialize.Inclusion.NON_NULL); // no more null-valued properties
or
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@JsonSerialize(include=JsonSerialize.Inclusion.NON_DEFAULT)
public class MyBean {
// ... only serialize properties with values other than what they default to
}