How to get Java 8 time classes to work on Jersey Jax-RS clients?

Question

You can tell how to configure ObjectMapper to automatically handle LocalDateTime class covered here:

serialize/deserialize java 8 java.time with Jackson JSON mapper

But when I try to use POJOs with java.time objects, Jersey fails to parse them with errors:

Java 8 date/time type `java.time.LocalDateTime` not supported by default: add Module "com.fasterxml.jackson.datatype:jackson-datatype-jsr310" to enable handling

But I do have that Maven dependency added.

How do you configure Jersey HTTP clients so that it uses ObjectMapper with the JavaTimeModule added when serializing json to objects?

Answer 1

You need to use the register method on the javax.ws.rs.client.Client to register a provider that can automatically convert using ObjectMapper.

JerseyObjectMapperProvider.java

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalTimeSerializer;
import lombok.extern.slf4j.Slf4j;

import javax.ws.rs.ext.ContextResolver;
import javax.ws.rs.ext.Provider;
import java.io.IOException;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
import java.util.Date;
import java.util.Objects;

@Provider
@Slf4j
public class JerseyObjectMapperProvider implements ContextResolver<ObjectMapper> {

    public static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
    static {
        OBJECT_MAPPER.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        OBJECT_MAPPER.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
        OBJECT_MAPPER.configure(SerializationFeature.WRITE_ENUMS_USING_TO_STRING, true);

        OBJECT_MAPPER.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

        JavaTimeModule javaTimeModule = new JavaTimeModule();

        javaTimeModule.addSerializer(Date.class, new JsonSerializer<>() {
            @Override
            public void serialize(Date value, JsonGenerator gen, SerializerProvider provider) throws IOException {
                provider.defaultSerializeValue(DateTimeFormatter.ISO_INSTANT.format(value.toInstant()), gen);
            }
        });

        javaTimeModule.addSerializer(LocalDate.class,
                new LocalDateSerializer(DateTimeFormatter.ISO_LOCAL_DATE));
        javaTimeModule.addSerializer(LocalTime.class,
                new LocalTimeSerializer(DateTimeFormatter.ISO_LOCAL_TIME));
        javaTimeModule.addSerializer(LocalDateTime.class,
                new LocalDateTimeSerializer(DateTimeFormatter.ISO_LOCAL_DATE_TIME));

        javaTimeModule.addDeserializer(Date.class, new JsonDeserializer<>() {
            @Override
            public Date deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
                if (Objects.isNull(p.getText())) {
                    return null;
                }

                return Date.from(Instant.parse(p.getText()));
            }
        });

        javaTimeModule.addDeserializer(LocalDate.class,
                new LocalDateDeserializer(DateTimeFormatter.ISO_LOCAL_DATE));
        javaTimeModule.addDeserializer(LocalTime.class,
                new LocalTimeDeserializer(DateTimeFormatter.ISO_LOCAL_TIME));
        javaTimeModule.addDeserializer(LocalDateTime.class,
                new LocalDateTimeDeserializer(DateTimeFormatter.ISO_LOCAL_DATE_TIME));

        OBJECT_MAPPER.registerModule(javaTimeModule);

        SimpleModule customModule = new SimpleModule();
        OBJECT_MAPPER.registerModule(customModule);
    }

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

Before using your Jersey client to access rest services, call this:

client.register(JerseyObjectMapperProvider.class);

Now you'll use the object mapper you created in the JerseyObjectMapperProvider class.