Spring Message Converter

Spring Message Converter

 

 

MappingJackson2HttpMessageConverter

An HttpMessageConverter implementation that can read and write JSON using Jackson’s ObjectMapper. JSON mapping can be customized as needed through the use of Jackson’s provided annotations. When further control is needed, a custom ObjectMapper can be injected through the ObjectMapper property for cases where custom JSON serializers/deserializers need to be provided for specific types. By default this converter supports ( application/json).

 

 

22.16.12 Message Converters

Customization of HttpMessageConverter can be achieved in Java config by overriding configureMessageConverters() if you want to replace the default converters created by Spring MVC, or by overriding extendMessageConverters() if you just want to customize them or add additional converters to the default ones.

Below is an example that adds Jackson JSON and XML converters with a customized ObjectMapper instead of default ones:

@Configuration
@EnableWebMvc
public class WebConfiguration extends WebMvcConfigurerAdapter {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder()
                .indentOutput(true)
                .dateFormat(new SimpleDateFormat("yyyy-MM-dd"))
                .modulesToInstall(new ParameterNamesModule());
        converters.add(new MappingJackson2HttpMessageConverter(builder.build()));
        converters.add(new MappingJackson2XmlHttpMessageConverter(builder.xml().build()));
    }

}

In this example, Jackson2ObjectMapperBuilder is used to create a common configuration for both MappingJackson2HttpMessageConverter and MappingJackson2XmlHttpMessageConverter with indentation enabled, a customized date format and the registration of jackson-module-parameter-names that adds support for accessing parameter names (feature added in Java 8).

	Enabling indentation with Jackson XML support requires woodstox-core-asl dependency in addition to jackson-dataformat-xml one.

Other interesting Jackson modules are available:

1. jackson-datatype-money: support for javax.money types (unofficial module)
2. jackson-datatype-hibernate: support for Hibernate specific types and properties (including lazy-loading aspects)