日期:2014-05-16  浏览次数:20342 次

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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up vote 3 down vote accepted

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:

  • Call ObjectMapper.getSerializationConfig().setSerializationInclusion() to define global setting (value enumeration JsonSerialize.Inclusion, with values ALWAYS, NON_NULL, NON_DEFAULT).

  • 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
  }