防止json结果中出现null值（春季）

Question

Right now, I have a lot of null values in my JSON result (talking about some 1000+), which I want to exclude from that result.

I've searched a lot and found a lot of questions/answers about this, but couldn't find something for my situation:

• I'm using Spring 4.0.1 and fasterxml.jackson 2.4.2
• I'm not using Spring Boot
• I cannot simply override the spring-mvc ObjectMapper, since there are a LOT of endpoints that would be affected by it
• My domain-model is auto-generated from an external XML file, so I can't add annotations to that domain-model

So basically I would like to do one of the following:

• Add the equivalent of annotations for auto-generated domain classes (eg setting on package structure or something)
• Override the ObjectMapper that Spring uses for one specific controller, to add objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

Is there any way to achieve this?

Thanks in advance!

Answer 1

I've solved my problem by implementing an own objectMapper for the controller. The webservices now must return a String instead of an object or a List

private ObjectMapper objectMapper;

@PostConstruct
private void configureObjectMapper() {
    objectMapper = new ObjectMapper();
    objectMapper.setSerializationInclusion(JsonInclude.Include.NON_EMPTY);
}

@RequestMapping(...)
@ResponseBody
public String getSomething(...) {
    try {
        return objectMapper.writeValueAsString(getSomething());
    } catch (JsonProcessingException e) {
        LOG.error("Could not serialize to JSON", e);
    }
    return null;
}