I am new to JAX-RS and I want to serve my list of items as JSON. My entity model is something like this:
public class Entity {
private String name;
private Date date;
private Float number;
}
This is how I am invoking the service:
@Path("/entities")
public class EntitiesController {
@GET
@Produces({"application/json"})
public List<Entity> getEntities() {
return EntityDAO.entitiesList();
}
}
However, the date is not formatted but is displayed as a long.
This answer shows how to format a date using a JsonSerializer. If I extend JsonSerializer, then where do I put that subclass in my project?
Answer
I figured a solution myself:
Under a new serializers package I created the CustomJsonDateSerializer class, which will be delegated the responsibility of formatting the date attribute thanks to the @JsonSerialize(...) annotation.
So I modified my Entity class adding that annotation ontop of the field:
@JsonSerialize(using = CustomJsonDateSerializer.class) private Date date;
And this is the content of CustomJsonDateSerializer:
package serializers;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import com.fasterxml.jackson.core.JsonGenerationException;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
public class CustomJsonDateSerializer extends JsonSerializer<Date> {
@Override
public void serialize(Date value, JsonGenerator jgen, SerializerProvider provider)
throws IOException, JsonGenerationException {
SimpleDateFormat formatter = new SimpleDateFormat("dd-MM-yyy");
String format = formatter.format(value);
jgen.writeString(format);
}
}