GlassFish JAX-RS Jackson custom JSON serialization

glassfish, jackson, java, jax-rs, jersey

Solution

Regarding the `@JsonSerialize` failure: If you have a getter of a field, you need to annotate the getter method with `@JsonSerialize` and not the field itself! It seems the getter method has a preference over the field on serialization. So the working code is:

import java.util.Calendar;
import org.codehaus.jackson.map.annotate.JsonSerialize;

public class FooBar {

    private Calendar calendar;

    public FooBar() {
        calendar = Calendar.getInstance();
    }

    @JsonSerialize(using=MySerializer.class)
    public Calendar getCalendar() {
        return calendar;
    }
}

Problem

I have a JAX-RS resource and I'd like to use a custom JSON serializer for `java.util.Calendar` attribute using the `@JsonSerialize(using=MySerializer.class)`. ``` import java.util.Calendar; import org.codehaus.jackson.map.annotate.JsonSerialize; public class FooBar { @JsonSerialize(using=MySerializer.class) private Calendar calendar; public FooBar() { calendar = Calendar.getInstance(); } public Calendar getCalendar() { return calendar; } } ``` MySerializer.java: ``` import java.io.IOException; import java.util.Calendar; import org.codehaus.jackson.JsonGenerator; import org.codehaus.jackson.JsonProcessingException; import org.codehaus.jackson.map.JsonSerializer; import org.codehaus.jackson.map.SerializerProvider; public class MySerializer extends JsonSerializer<Calendar> { @Override public void serialize(Calendar c, JsonGenerator jg, SerializerProvider sp) throws IOException, JsonProcessingException { jg.writeString("fooBar Calendar time: " + c.getTime()); } } ``` I made a simple project in NetBeans 7.1 and it works well. When I use it in an other project with different deployment (EAR with multiple WARs and EJB JARs) then I receive ``` javax.ws.rs.WebApplicationException: com.sun.jersey.api.MessageException: A message body writer for Java class com.example.FooBar and MIME media type application/json was not found ``` But if I put into the web.xml the init-parameter ``` <init-param> <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name> <param-value>true</param-value> </init-param> ``` json serialization works, but the `@JsonSerialize` annotation does not work. On the other hand the Netbeans project does't need `POJOMappingFeature`. What could be the difference between these two applications? What makes a difference where one application needs `POJOMappingFeature` and the other one don't?

Original source