Is it possible to create overloaded setters for Jackson/POJO mapper? - serialization

Question

I have a class:
#Column(name = "data", nullable = false)
String data;
public void setData(final String data) {
this.data = data;
}
public void setDataAsSet(final Set<String> strings) {
setData(JOINER.join(strings));
}
Can Jackson serialize / de-serialize it?
Ideally I would like to (at least) support de-serialization.
I've searched the web and found no clear answer. Some bug reports, and suggestions to #ignore the 'un-necessary' getter / setter, but I want all of them.
Thanks.

Answer 1

It seems to be possible with writing custom deserializer. Unfortunately have no opportunity to set the env now and try. But in general I don't it's a good idea to send same data as String or Set<String>. It will result in hard to debug bugs or other unpredictable problems. There should be two separately declared fields or it should always be a collection (in most cases it will probably have single element). Rethink it please.
I still encourage You to rethink the design nevertheless did it:
Bean:
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
public class SampleBean {
#JsonDeserialize(using = SampleDeserializer.class)
public String data;
}
Deserializer:
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import java.io.IOException;
import java.util.List;
import static com.fasterxml.jackson.core.JsonToken.VALUE_STRING;
public class SampleDeserializer extends JsonDeserializer<String> {
#Override
public String deserialize(JsonParser jp, DeserializationContext ctx) throws IOException {
JsonToken jt = jp.getCurrentToken();
if (jt == VALUE_STRING) {
return jp.getValueAsString();
} else if (jt == JsonToken.START_ARRAY) {
return jp.readValueAs(List.class).toString().replace("[", "").replace("]", "").replaceAll("\\s*", "");// joining could be done much better of course
}
return null;
}
}
Test:
import com.fasterxml.jackson.databind.ObjectMapper;
import org.junit.Assert;
import org.junit.Test;
import java.io.IOException;
public class SampleTest {
#Test
public void test() throws IOException {
final String json = "{\"data\":\"2\"}";
final String json2 = "{\"data\":[\"2\",\"3\"]}";
ObjectMapper om = new ObjectMapper();
SampleBean sb = om.readValue(json, SampleBean.class);
Assert.assertEquals("2", sb.data);
sb = om.readValue(json2, SampleBean.class);
Assert.assertEquals("2,3", sb.data);
}
}