For now, I am using something like this:
#RequestBody
#RequestMapping("whatever")
public ObjectWrapper<Integer> foo() {
return new ObjectWrapper<>(42);
}
What I would like to do is to rewrite the method in the following way
#RequestBody
#RequestMapping("whatever")
public int foo() {
return 42;
}
and get 42 (or any other primitive) wrapped into ObjectWrapper before it gets serialized (by Jackson) and gets written into response. I wonder if it is actually possible and, if so, how to do that.
As I have misunderstood your question, I updated my answer:
public class CustomObjectMapper extends ObjectMapper {
public CustomObjectMapper() {
super();
super.configure(SerializationFeature.WRAP_ROOT_VALUE, true);
}
}
Add to default message converter:
<mvc:message-converters>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper" ref="jacksonObjectMapper" />
</bean>
</mvc:message-converters>
<bean id="jacksonObjectMapper" class="com.mysite.CustomObjectMapper" />
However this might not produce the output you desired.
Best thing is to write your own serializer and use it with your custom object mapper and wrap primitives in your serializer.
Here is something related: https://github.com/FasterXML/jackson-databind/issues/34
Related
Using Spring Data REST with JPA in version 2.1.0.
How can I configure the pagination in order to have the page argument starting at index 1 instead of 0 ?
I have tried setting a custom HateoasPageableHandlerMethodArgumentResolver with an mvc:argument-resolvers, but that doesn't work:
<mvc:annotation-driven>
<mvc:argument-resolvers>
<bean class="org.springframework.data.web.HateoasPageableHandlerMethodArgumentResolver">
<property name="oneIndexedParameters" value="true"/>
</bean>
</mvc:argument-resolvers>
</mvc:annotation-driven>
Note that this behaviour is perfectly coherent with the documentation for mvc:argument-resolver that says:
Using this option does not override the built-in support for
resolving handler method arguments. To customize the built-in support
for argument resolution configure RequestMappingHandlerAdapter
directly.
But how can I achieve this ? If possible, in a clean and elegant way ?
The easiest way to do so is to subclass RepositoryRestMvcConfiguration and include your class into your configuration:
class CustomRestMvcConfiguration extends RepositoryRestMvcConfiguration {
#Override
#Bean
public HateoasPageableHandlerMethodArgumentResolver pageableResolver() {
HateoasPageableHandlerMethodArgumentResolver resolver = super.pageableResolver();
resolver.setOneIndexedParameters(true);
return resolver;
}
}
In your XML configuration, replace:
<bean class="….RepositoryRestMvcConfiguration" />
with
<bean class="….CustomRestMvcConfiguration" />
or import the custom class instead of the standard one in your JavaConfig file.
I have configured the RequestMappingHandlerAdapter using a BeanPostProcessor, however I believe that's neither clean, nor elegant. That looks more like a hack. There must be a better way ! I'm giving the code below just for reference.
public class RequestMappingHandlerAdapterCustomizer implements BeanPostProcessor {
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
if (bean instanceof RequestMappingHandlerAdapter) {
RequestMappingHandlerAdapter adapter = (RequestMappingHandlerAdapter)bean;
List<HandlerMethodArgumentResolver> customArgumentResolvers = adapter.getCustomArgumentResolvers();
if(customArgumentResolvers != null) {
for(HandlerMethodArgumentResolver customArgumentResolver : customArgumentResolvers) {
if(customArgumentResolver instanceof HateoasPageableHandlerMethodArgumentResolver) {
HateoasPageableHandlerMethodArgumentResolver hateoasPageableHandlerMethodArgumentResolver = (HateoasPageableHandlerMethodArgumentResolver)customArgumentResolver;
hateoasPageableHandlerMethodArgumentResolver.setOneIndexedParameters(true);
}
}
}
}
return bean;
}
public Object postProcessBeforeInitialization(Object bean, String beanName)
throws BeansException {
return bean;
}
}
<beans ...>
<bean class="util.spring.beanpostprocessors.RequestMappingHandlerAdapterCustomizer" />
</beans>
I use to do it using a customizer, which is something that they keep adding for more and more components with every new version:
#Bean
public PageableHandlerMethodArgumentResolverCustomizer pageableResolverCustomizer() {
return resolver -> resolver.setOneIndexedParameters(true);
}
You can put this in any #Configuration class, but ideally you should put it (with any other customization) in one that implements RepositoryRestConfigurer.
I want the convenience of automatically serializing objects into JSON and ability to return raw JSON string. I am using Gson instead of Jackson, since Gson has been in my app for a while and I have existing tweaks, converters, and annotations peppered throughout my app.
<mvc:annotation-driven >
<mvc:message-converters register-defaults="true">
<bean class="com.test.GSONHttpMessageConverter" />
</mvc:message-converters>
</mvc:annotation-driven>
I can automatically serialize pojo's:
#RequestMapping(value="foo/{name}", method = RequestMethod.GET)
public #ResponseBody Shop getShopInJSON(#PathVariable String name) {
return new Shop();
}
I want this to work also:
#RequestMapping(value="rawJsonTest/{name}", method = RequestMethod.GET, produces=MediaType.APPLICATION_JSON_VALUE)
public #ResponseBody String rawJsonTest(#PathVariable String name) {
return "{\"test\":5}";
}
Result right now is an escaped value:
"{\"test\":5}"
instead of:
{"test":5}
The problem is that your custom converter takes precedence over the default ones. It's thus called, considers the String as a raw String that must be converted to JSON, and thus escapes the double quotes.
I'm not sure if and how it's possible with XML to register a converter after (and not before) the default ones, but you could set register-defaults to false and provide an explicit list of all the converters you want to apply. If org.springframework.http.converter.StringHttpMessageConverter is registered before your custom one, it will be called first and will send the returned String as is.
Thanks for the correct answer, #JB Nizet
Order matters:
<mvc:annotation-driven >
<mvc:message-converters register-defaults="true">
<bean class = "org.springframework.http.converter.StringHttpMessageConverter">
<property name="supportedMediaTypes" value="application/json; charset=UTF-8" />
</bean>
<bean class="com.test.GSONHttpMessageConverter" />
</mvc:message-converters>
I have below Serializer for JodaTime handling:
public class JodaDateTimeJsonSerializer extends JsonSerializer<DateTime> {
private static final String dateFormat = ("MM/dd/yyyy");
#Override
public void serialize(DateTime date, JsonGenerator gen, SerializerProvider provider)
throws IOException, JsonProcessingException {
String formattedDate = DateTimeFormat.forPattern(dateFormat).print(date);
gen.writeString(formattedDate);
}
}
Then, on each model objects, I do this:
#JsonSerialize(using=JodaDateTimeJsonSerializer.class )
public DateTime getEffectiveDate() {
return effectiveDate;
}
With above settings, #ResponseBody and Jackson Mapper sure works. However, I don't like the idea where I keep writing #JsonSerialize. What I need is a solution without the #JsonSerialize on model objects. Is it possible to write this configuration somewhere in spring xml as a one configuration?
Appreciate your help.
Although you can put an annotation for each date field, is better to do a global configuration for your object mapper. If you use jackson you can configure your spring as follow:
<bean id="jacksonObjectMapper" class="com.company.CustomObjectMapper" />
<bean id="jacksonSerializationConfig" class="org.codehaus.jackson.map.SerializationConfig"
factory-bean="jacksonObjectMapper" factory-method="getSerializationConfig" >
</bean>
For CustomObjectMapper:
public class CustomObjectMapper extends ObjectMapper {
public CustomObjectMapper() {
super();
configure(Feature.WRITE_DATES_AS_TIMESTAMPS, false);
setDateFormat(new SimpleDateFormat("EEE MMM dd yyyy HH:mm:ss 'GMT'ZZZ (z)"));
}
}
Of course, SimpleDateFormat can use any format you need.
#Moesio pretty much got it. Here's my config:
<!-- Configures the #Controller programming model -->
<mvc:annotation-driven/>
<!-- Instantiation of the Default serializer in order to configure it -->
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapterConfigurer" init-method="init">
<property name="messageConverters">
<list>
<bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
<property name="objectMapper" ref="jacksonObjectMapper" />
</bean>
</list>
</property>
</bean>
<bean id="jacksonObjectMapper" class="My Custom ObjectMapper"/>
<bean id="jacksonSerializationConfig" class="org.codehaus.jackson.map.SerializationConfig"
factory-bean="jacksonObjectMapper" factory-method="getSerializationConfig" />
The bit that got me is that <mvc:annotation-driven/> makes its own AnnotationMethodHandler and ignores the one you make manually. I got the BeanPostProcessing idea from http://scottfrederick.blogspot.com/2011/03/customizing-spring-3-mvcannotation.html to configure the one that gets used, and voilà! Works like a charm.
Same using JavaConfig of Spring 3:
#Configuration
#ComponentScan()
#EnableWebMvc
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;
}
}
If you are using Spring Boot, try this in application.yml :
spring:
jackson:
date-format: yyyy-MM-dd
time-zone: Asia/Shanghai
joda-date-time-format: yyyy-MM-dd
If you simply have the Jackson JARs on your classpath, and return a #ResponseBody, Spring will automatically convert the Model object to JSON. You don't need to annotate anything in the Model to get this to work.
Using Spring 3 and Jackson 1.7.6, I can serialize implementations of an abstract class and output the fully-qualified name of the class as a property called #class. This works fine when my Spring controllers return a single instance from a controller annotated with #ResponseBody.
When returning a Collection of the above types the resulting JSON changes according to which type is being serialized (fields from each subclass are present), but it does not include the #class property, which our client code needs.
How can I get this type hint into the serialized JSON when returning a collection?
//Returns complete with #class=com.package.blah
#RequestMapping("/json/getProduct.json")
public #ResponseBody Product getProduct(Integer id)
{
return service.getProduct(id);
}
//Does not include #class
#RequestMapping("/json/getProducts.json")
public #ResponseBody List<Product> getProducts()
{
return service.getProducts();
}
In order to do this you will need to configure ObjectMapper. This is not straightforward via Spring, as rather than settable properties, ObjectMapper has invokable methods that set its state (and then it stores this as a bitmask).
If you are using <mvc:annotation-driven /> you will need to replace it with the equivalent markup, which can be found in the Spring JavaDocs.
Extend ObjectMapper:
public class ConfigurableObjectMapper extends ObjectMapper
{
public ConfigurableObjectMapper()
{
this.enableDefaultTypingAsProperty(DefaultTyping.JAVA_LANG_OBJECT, JsonTypeInfo.Id.CLASS.getDefaultPropertyName());
}
}
Then tell Spring to use an instance of this class instead of the default implementation.
<bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
<property name="order" value="0" />
</bean>
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="webBindingInitializer">
<bean class="org.springframework.web.bind.support.ConfigurableWebBindingInitializer">
<property name="validator" ref="validator" />
</bean>
</property>
<property name="messageConverters">
<list>
<bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
<property name="objectMapper">
<bean class="com.blitzgamesstudios.web.common.json.ConfigurableObjectMapper" />
</property>
</bean>
<bean class="org.springframework.http.converter.ByteArrayHttpMessageConverter" />
<bean class="org.springframework.http.converter.StringHttpMessageConverter" />
<bean class="org.springframework.http.converter.FormHttpMessageConverter" />
<bean class="org.springframework.http.converter.xml.SourceHttpMessageConverter" />
</list>
</property>
</bean>
<bean id="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean" />
You can use #JsonTypeInfo with POJOs, Collections and Maps, but note that the declared value type of Collections and Maps must be one that has (or inherits) #JsonTypeInfo annotation (when using per-class #JsonTypeInfo annotation). This would not work, for example, if you have type like "Collection" -- in this case, Deejay's answer is correct, as you can force inclusion with "default typing" option.
But things should also work if you have a Collection property to serialize/deserialize, i.e.:
public class Bean {
#JsonTypeInfo(....)
public Collection<Object> listOfObjects; // does work because it's per-property annotation!
// ... also, applies to value type and not Collection type itself
}
since that will override any #JsonTypeInfo annotations value type might otherwise have
I had the problem withjava.util.Map, so I did something like:
public interface MyMap extends Map<Long, Product> {}
and
public class MyHashMap extends HashMap<Long, Product> implements MyMap {}
Found on: http://jackson-users.ning.com/forum/topics/mapper-not-include-type-information-when-serializing-object-why
Object mapper bean can enable default typing:
ObjectMapper mapper = new ObjectMapper()
mapper.enableDefaultTyping(DefaultTyping.NON_FINAL, As.PROPERTY);
This will give the json output as following:
[
"java.util.ArrayList",
[
{
"#class": "com.xyz.Product",
"name": "myName"
}
]
]
I am using Jackson JSON in a Spring 3 MVC app. To not serialize each and every single Date field, I created a custom objectmapper that uses a specific DateFormat:
#Component("jacksonObjectMapper")
public class CustomObjectMapper extends ObjectMapper
{
Logger log = Logger.getLogger(CustomObjectMapper.class);
#PostConstruct
public void afterProps()
{
log.info("PostConstruct... RUNNING");
//ISO 8601
getSerializationConfig().setDateFormat(new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SZ"));
}
//constructors...
}
This custom ObjectMapper is injected into the JsonConverter:
<bean id="jsonConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
<property name="supportedMediaTypes" value="application/json" />
<property name="objectMapper" ref="jacksonObjectMapper" /> <!-- defined in CustomObjectMapper -->
</bean>
There is no exception in the logs and serialization works, but it is not picking up the dateformat, it simple serializes to a timestamp. The #PostConstruct annotation works, the log statement in the method is in the logs.
Does anyone know why this fails?
You may also need to specify that you want textual Date serialization, by doing:
configure(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS, false);
(although I was assuming setting non-null date format might also trigger it, but maybe not)
Also, you can do configuration of mapper directly from constructor (which is safe). Not that it should change behavior, but would remove need for separate configuration method.
I've done the below which works to get around compatability with Java / PHP timestamps. Java uses milliseconds since EPOCH and PHP uses seconds so was simpler to use ISO dates.
I declare the below message adapters:
<bean id="messageAdapter"
class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="messageConverters">
<list>
<bean id="jacksonJsonMessageConvertor"
class="my.app.MyMappingJacksonHttpMessageConverter"/>
</list>
</property>
</bean>
And MyMappingJacksonHttpMessageConverter looks like the below:
public class MyMappingJacksonHttpMessageConverter extends MappingJacksonHttpMessageConverter {
public MyMappingJacksonHttpMessageConverter(){
super();
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(Feature.WRITE_DATES_AS_TIMESTAMPS, false);
setObjectMapper(objectMapper);
}
}
With the above all dates are written out in ISO format.
For Spring config application.properties
spring.jackson.serialization.fail-on-empty-beans=false