Jackson Object Mapper in spring MVC not working - json

Question

Every object with Date format is being serialized as a long.
I've read around that I need to create a custom object mapper
and so I did:
public class CustomObjectMapper extends ObjectMapper {
public CustomObjectMapper() {
super();
configure(Feature.WRITE_DATES_AS_TIMESTAMPS, false);
setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
}
}
I've also registered that custom mapper as a converter
#Override
protected void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
converters.add(converter());
addDefaultHttpMessageConverters(converters);
}
#Bean
MappingJacksonHttpMessageConverter converter() {
MappingJacksonHttpMessageConverter converter = new MappingJacksonHttpMessageConverter();
converter.setObjectMapper(new CustomObjectMapper());
return converter;
}
but still, it doesn't work, and I recieve a long as a date.
Any idea what am I doing wrong?

Answer 1

You'll need to implement your own Dateserializer, just like the following (got it from this tutorial, so props to Loiane, not me ;-) ):
package ....util.json;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.map.JsonSerializer;
import org.codehaus.jackson.map.SerializerProvider;
import org.springframework.stereotype.Component;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
#Component
public class JsonDateSerializer extends JsonSerializer<Date>{
private static final SimpleDateFormat dateFormat = new SimpleDateFormat("dd.MM.yyyy HH:mm "); // change according to your needs
#Override
public void serialize(Date date, JsonGenerator gen, SerializerProvider provider)
throws IOException {
String formattedDate = dateFormat.format(date);
gen.writeString(formattedDate);
}
}
then you could just add the following annotation to your Date-Objects and it will persist fine:
#JsonSerialize(using = JsonDateSerializer.class)
public Date getCreated() {
return created;
}
At least it works with spring 3.2.4 and jackson 1.9.13 here.
edit: Think about using FastDateFormat instead of SimpleDateFormat, for it's the threadsafe-alternative (as mentioned in the comments of Loianes article)

Answer 2

Try adding 0 as index in #add()
#Configuration
#ComponentScan()
#EnableWebMvc
#PropertySource("classpath:/web.properties")
public class WebConfig extends WebMvcConfigurerAdapter
{
#Override
public void configureMessageConverters(final List<HttpMessageConverter<?>> converters)
{
converters.add(0, jsonConverter());
}
#Bean
public MappingJacksonHttpMessageConverter jsonConverter()
{
final MappingJacksonHttpMessageConverter converter = new MappingJacksonHttpMessageConverter();
converter.setObjectMapper(new CustomObjectMapper());
return converter;
}
}
It worked for me.