Jackson2 custom deserializer factory - jackson

Question

I am porting jackson 1.6 code to jackson 2 and stumbled upon a deprecated code.
What i did in jackson 1.6 is:
CustomDeserializerFactory sf = new CustomDeserializerFactory();
mapper.setDeserializerProvider(new StdDeserializerProvider(sf));
sf.addSpecificMapping(BigDecimal.class, new BigDecimalDeserializer());
t = mapper.readValue(ts, X[].class);
Anyone knows how to do it in jackson 2?

Answer 1

To add a factory--not just a deserializer--don't use SimpleModule. Create your own Module and within it create a Deserializers object that is added to the SetUpContext. The Deserializers object will have access to similar methods that the factory did where you can get extra type information about the deserializer needed.
It will look something like this (note that it doesn't need to be an inner class):
public class MyCustomCollectionModule extends Module {
#Override
public void setupModule(final SetupContext context) {
context.addDeserializers(new MyCustomCollectionDeserializers());
}
private static class MyCustomCollectionDeserializers implements Deserializers {
...
#Override
public JsonDeserializer<?> findCollectionDeserializer(final CollectionType type, final DeserializationConfig config, final BeanDescription beanDesc, final TypeDeserializer elementTypeDeserializer, final JsonDeserializer<?> elementDeserializer) throws JsonMappingException {
if (MyCustomCollection.class.equals(type.getRawClass())) {
return new MyCustomCollectionDeserializer(type);
}
return null;
}
...
}
}

Answer 2

In Jackson 2.0:
Create a Module (usually SimpleModule)
Register custom handlers with it.
Call ObjectMapper.registerModule(module);.
This is available on Jackson 1.x as well (since 1.8 or so).

Answer 3

Here is an example of registering a module (in this case Joda date handling) in Jackson 2.x:
ClientConfig clientConfig = new DefaultClientConfig();
ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JodaModule());
mapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
JacksonJsonProvider provider = new JacksonJsonProvider();
provider.configure(SerializationFeature.INDENT_OUTPUT, true);
provider.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
provider.setMapper(mapper);
clientConfig.getSingletons().add(provider);
Client client = Client.create(clientConfig);

Answer 4

Exemplifying #StaxMan answer
Basically you need to create a module (SimpleModule), add a deserializer and register this module
final SimpleModule sm = new SimpleModule();
sm.addDeserializer(Date.class, new JsonDeserializer<Date>(){
#Override
public Date deserialize(JsonParser p, DeserializationContext ctxt)
throws IOException {
try {
System.out.println("from my custom deserializer!!!!!!");
return new SimpleDateFormat("yyyy-MM-dd").parse(p.getValueAsString());
} catch (ParseException e) {
System.err.println("aw, it fails: " + e.getMessage());
throw new IOException(e.getMessage());
}
}
});
final CreationBean bean = JsonUtils.getMapper()
.registerModule(sm)
// .setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"))
.readValue("{\"dateCreation\": \"1995-07-19\"}", CreationBean.class);
Here a fully example
import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.module.SimpleModule;
/**
* #author elvis
* #version $Revision: $<br/>
* $Id: $
* #since 8/22/16 8:38 PM
*/
public class JackCustomDeserializer {
public static void main(String[] args) throws IOException {
final SimpleModule sm = new SimpleModule();
sm.addDeserializer(Date.class, new JsonDeserializer<Date>(){
#Override
public Date deserialize(JsonParser p, DeserializationContext ctxt)
throws IOException {
try {
System.out.println("from my custom deserializer!!!!!!");
return new SimpleDateFormat("yyyy-MM-dd").parse(p.getValueAsString());
} catch (ParseException e) {
System.err.println("aw, it fails: " + e.getMessage());
throw new IOException(e.getMessage());
}
}
});
final CreationBean bean = JsonUtils.getMapper()
.registerModule(sm)
// .setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"))
.readValue("{\"dateCreation\": \"1995-07-19\"}", CreationBean.class);
System.out.println("parsed bean: " + bean.dateCreation);
}
static class CreationBean {
public Date dateCreation;
}
}