Imtiaz Mirza Imtiaz Mirza - 6 months ago 142
Java Question

Jersey consuming/ parsing Java 8 date time

This is my user class, and I to save ISO compliant date time in my database.

public class User {

@Id
private String id;

private String email;

@DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME)
private LocalDateTime loginDate;

}


Here is my Jersey controller:

@POST
@Consumes("application/json")
@Produces("application/json")

public Response create( User user) {

Map<Object, Object> apiResponse = new HashMap<Object, Object>();
Map<Object, Object> response = new HashMap<Object, Object>();


user = (User) userService.create(user);

}


How can can I consume a datetime format like this one in jersey? Is it possible to send a datatime
String
and create Java 8 date time object automatically?

{
"email" : "imz.mrz@gmail.com"
"loginDate" : "2015-04-17T06:06:51.465Z"
}


#

Update:

I was using Spring boot jersey, and had other jsr packages

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jersey</artifactId>
</dependency>


So I removed all the packages except from spring-boot-jersey package.
use this annotation for LocalDateTime

@JsonDeserialize(using = LocalDateTimeDeserializer.class)


This way I can consume ISODate and save ISODate() to mongodb and produce full formated mongodb LocalDateTime to frontend.

Problem solved.

Answer

Couple options I see...

Option 1:

Assuming you have JAXB annotation support with Jackson as the JSON provider...

You could use an XmlAdapter. For example

public class LocalDateTimeAdapter extends XmlAdapter<String, LocalDateTime> {

    @Override
    public LocalDateTime unmarshal(String dateString) throws Exception {
        Instant instant = Instant.parse(dateString);
        LocalDateTime dateTime = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());
        return dateTime;
    }

    @Override
    public String marshal(LocalDateTime dateTime) throws Exception {
        Instant instant = dateTime.toInstant(ZoneOffset.UTC);
        return DateTimeFormatter.ISO_INSTANT.format(instant);
    }
}

See the Instant API for more information.

Then you can just annotate the field/property with the adapter

@XmlJavaTypeAdapter(LocalDateTimeAdapter.class)
private LocalDateTime loginDate;

You could also declare the annotation at the package level, so that all uses in the package will use the adapter, without the need to annotate. You do so in a file named package-info.java put inside the package

@XmlJavaTypeAdapters({
    @XmlJavaTypeAdapter(type = LocalDateTime.class, 
                        value = LocalDateTimeAdapter.class)
})
package thepackage.of.the.models;

import java.time.LocalDateTime;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapters;

Option 2:

Use the Jackson APIs directly. Meaning, use a JsonDeserializer and JsonSerializer. For example

public class LocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> {

    @Override
    public LocalDateTime deserialize(JsonParser jp, 
            DeserializationContext dc) throws IOException, JsonProcessingException {
        ObjectCodec codec = jp.getCodec();
        TextNode node = (TextNode)codec.readTree(jp);
        String dateString = node.textValue();
        Instant instant = Instant.parse(dateString);
        LocalDateTime dateTime = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());
        return dateTime;
    } 
}

public class LocalDateTimeSerializer extends JsonSerializer<LocalDateTime> {

    @Override
    public void serialize(LocalDateTime dateTime, JsonGenerator jg, 
            SerializerProvider sp) throws IOException, JsonProcessingException {
        Instant instant = dateTime.toInstant(ZoneOffset.UTC);
        jg.writeString(DateTimeFormatter.ISO_INSTANT.format(instant));
    } 
}

You can apply this at the field/property level

@JsonSerialize(using = LocalDateTimeSerializer.class)
@JsonDeserialize(using = LocalDateTimeDeserializer.class)
public LocalDateTime loginDate; 

Or at the ObjectMapper level (so you don't need to annotate everywhere)

@Provider
@Consumes(MediaType.APPLICATION_JSON)
@Produces(MediaType.APPLICATION_JSON)
public class ObjectMapperContextResolver implements ContextResolver<ObjectMapper> {

    final ObjectMapper mapper = new ObjectMapper();

    public ObjectMapperContextResolver() {
        SimpleModule module = new SimpleModule();
        module.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer());
        module.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer());
        mapper.registerModule(module);
        // add JAXB annotation support if required
        mapper.registerModule(new JaxbAnnotationModule());
    }

    @Override
    public ObjectMapper getContext(Class<?> type) {
        return mapper;
    }  
}

Basically what happens, is that the MessageBodyWriter/MessageBodyReader used for ummarshalling/marshalling, will call the getContext method to get the ObjectMapper

Note:

  • The above solutions will parse from the format 2007-12-03T10:15:30.00Z, as documented in Instant.parse, and will serialize to the same format, as documented in DateTimeFormatter.ISO_INSTANT

  • The above is also assuming you are using Jackson as the Serializer. I used the below dependency (with Jersey 2.16) to test

    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-json-jackson</artifactId>
        <version>2.16</version>
    </dependency>
    

    The dependency uses a JacksonJaxbJsonProvider for JAXB annotation support. If you are using a lower version of Jersey like 1.x, the jersey-json dependency should offer JAXB annotation support, if you enable the POJO mapping feature. Alternatively for Jersey 1.x, if you want to use Jackson 2, you can use this dependency

    <dependency>
        <groupId>com.fasterxml.jackson.jaxrs</groupId>
        <artifactId>jackson-jaxrs-json-provider</artifactId>
        <version>2.4.0</version>
    </dependency>
    

    which is actually what is used by jersey-media-json-jackson. So you could explicitly register the JacksonJaxbJsonProvider, or add the Jackson package (com.fasterxml.jackson.jaxrs.json) to list packages to scan


UPDATE

See Also: