Serializing a POJO based on a runtime whitelist of properties

Question

Is it possible to serialize a whitelisted subset of a POJO's properties (where the whitelist is known only at runtime) using Jackson?

All the solutions I know of so far (Views, @JsonIgnoreProperties etc.) are static, compile-time solutions.

Further, my backend returns results in the following format:

{
    "outcome": "SUCCESS", // an enum
    "message": "Success.", // a message for the developer
    "result": {
        // Some result that's different for each call
    }
}

So I am looking for a solution that can be applied to only parts of the object graph (like the contents of the result property).

You could use a JSON filter. – cassiomolin Oct 10 '17 at 12:44 — cassiomolin, Oct 10 '17 at 12:44

ptomli · Accepted Answer · 2017-10-11T06:25:22.920

3

You probably want to look at @JsonFilter.

See this tutorial on serializing only fields that meet some criteria which includes details of this, and a couple of other methods.

For completeness

@JsonFilter("pojo-filter")
class Pojo {
    public int foo;
}

FilterProvider filters = new SimpleFilterProvider()
    .addFilter("pojo-filter", new SimpleBeanPropertyFilter() {
        @Override
        protected boolean include(PropertyWriter writer) {
            return "foo".equals(writer.getName()) 
                ? Random.nextBoolean()
                : true;
        }
    });

new ObjectMapper().writer().filters(filters).write(new Pojo());

Globally you can use ObjectMapper.setFilterProvider

edited Oct 11 '17 at 06:25

answered Oct 10 '17 at 12:44

ptomli

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This means I have to obtain a writer from the `ObjectMapper` for every thread, add the `FilterProvider` and then serialize my object graph, correct? Wouldn't this add runtime overhead? – markvgti Oct 11 '17 at 00:24
You can use `ObjectMapper.setFilterProvider` – ptomli Oct 11 '17 at 06:47
Using a filter works for me in may situations. Thanks. – markvgti Oct 14 '17 at 06:35

Serializing a POJO based on a runtime whitelist of properties

1 Answers1