I'm building a Spring application which has #RestController, like:
#RestController
#RequestMapping(value = "/master")
public class MyController {
#Autowired
private MyService service;
#PostMapping("/call")
public ResponseEntity<Boolean> apiCall(#RequestBody MyDTO myDto) { ;
return new ResponseEntity<Boolean>(service.apiCall(myDto), OK);
}
}
And a request object:
public class MyDTO {
#JsonProperty("emp_number")
private long empNumber;
#JsonProperty("office_id")
private long officeId;
// ....constructors, etc.
}
In request json I want officeId to be not null.
So far I've tried marking the officeId field as:
#com.fasterxml.jackson.databind.annotation.JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
#JsonProperty(required = true)
#javax.validation.constraints.NotNull
But in the request json, even if I miss office_id, it is not throwing any error.
What am I missing?
It could be that in your case you are deserializing request, and missing primitive properties which are referenced by constructor are assigned a default value
java defaults
You could try to use corresponding Long wrapper object for MyDTO instead of primitives or maybe deserialization feature FAIL_ON_NULL_FOR_PRIMITIVES
You have to change the type from primitive to wrapper otherwise the default value of 0 will be considered and validation will pass.
Annotate MyDTO with #Valid annotation.
When Spring Boot finds an argument annotated with #Valid, it automatically bootstraps the default JSR 380 implementation — Hibernate Validator — and validates the argument.
from here
Please add following dependency to pom.xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
PS: i have made minor adjustments to response structure to see the error in response
Entire code is as follows:
package com.example.spring.java.springjavasamples;
import com.fasterxml.jackson.annotation.JsonProperty;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.validation.Valid;
import javax.validation.constraints.NotNull;
import java.util.HashMap;
import java.util.Map;
#SpringBootApplication
public class SpringJavaSamplesApplication {
public static void main(String[] args) {
SpringApplication.run(SpringJavaSamplesApplication.class, args);
}
}
#RestController
#RequestMapping(value = "/master")
class MyController {
private final MyService service;
public MyController(MyService service) {
this.service = service;
}
#PostMapping("/call")
public ResponseEntity<Map<String, Object>> apiCall(#Valid #RequestBody MyDTO myDto, BindingResult bindingResult) {
if (bindingResult.hasErrors()) {
Map<String, String> errors = new HashMap<>();
bindingResult.getAllErrors().forEach((error) -> {
String fieldName = ((FieldError) error).getField();
String errorMessage = error.getDefaultMessage();
errors.put(fieldName, errorMessage);
});
return prepareResponse("error", errors, HttpStatus.BAD_REQUEST);
} else {
return prepareResponse("data", service.apiCall(myDto), HttpStatus.OK);
}
}
private ResponseEntity<Map<String, Object>> prepareResponse(String key, Object data, HttpStatus status) {
Map<String, Object> map = new HashMap<>();
map.put(key, data);
return new ResponseEntity<>(map, status);
}
}
class MyDTO {
#NotNull(message = "Employee number cannot be null")
#JsonProperty("emp_number")
private Long empNumber;
#NotNull(message = "Office Id cannot be null")
#JsonProperty("office_id")
private Long officeId;
#Override
public String toString() {
return "MyDTO{" +
"empNumber=" + empNumber +
", officeId=" + officeId +
'}';
}
}
#Service
class MyService {
public String apiCall(MyDTO myDto) {
System.out.println("all valid: " + myDto);
return myDto.toString();
}
}
I am using Jackson XML mapper to deserialize XML to POJO. The XML looks like
<person>
<agency>
<phone>111-111-1111</phone>
</agency>
</person>
And my class looks like
class Person
{
#JacksonXmlProperty(localName="agency", namespace="namespace")
private Agency agency;
//getter and setter
}
class Agency
{
#JacksonXmlElementWrapper(useWrapping = false)
#JacksonXmlProperty(localName="phone", namespace="namespace")
private List<AgencyPhone> phones;
//getter and setter
}
class AgencyPhone
{
private Phone phone;
//getter and setter
}
class Phone
{
private String number;
//getter and setter
}
I want to set the phone number to number in Phone class. I cannot change XML or the way the class has been structured. I am getting Cannot construct instance of resolved.agency.AgencyPhone error and I created a AgencyPhone constructor
class AgencyPhone{
{
private Phone phone;
public AgencyPhone(Phone phone)
{
this.phone = phone;
}
}
But that did not work. So how to deserialize to nested instances.
You can write your own custom deserialiser to achieve this. Here is the code to get you started:
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.dataformat.xml.XmlMapper;
import java.io.IOException;
public class Test {
public static void main(String[] args) throws JsonParseException, JsonMappingException, IOException {
XmlMapper mapper = new XmlMapper();
final SimpleModule module = new SimpleModule("configModule", com.fasterxml.jackson.core.Version.unknownVersion());
module.addDeserializer(Person.class, new DeSerializer());
mapper.registerModule(module);
// Person readValue = mapper.readValue(<xml source>);
}
}
class DeSerializer extends StdDeserializer<Person> {
protected DeSerializer() {
super(Person.class);
}
#Override
public Person deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException {
// use p.getText() and p.nextToken to navigate through the xml and construct Person object
return new Person();
}
}
One can ignore a property of a class using #JsonIgnorePropertiesas a class level annotation. But let's say you have the following two classes;
class Client {
#JsonIgnoreProperties ("owner")
List<Vehicle> vehicles;
}
Class Vehicle {
#JsonIgnoreProperties ("vehicles")
Client owner;
}
I thought this would work. But apparently The JsonIgnoreProperties doesn't work on the list. I imagine it checks java.util.List for property òwner`but it doesn't find it.
What i want is a filter based on which object is retrieved first. If the Vehicle was retrieved first, show the owner but don't show the vehicles that Client has. And if the Clientis retrieved first, show vehicles but don't show each Vehicle's owner. This was too avoid the unending recursion.
My question is how can i ignore the property owner in the objects of Vehicle in the list vehicles in Client?
EDIT
Using #Kushan answer.
#JsonIgnoreProperties ("owner")
Class Vehicle {
Client owner;
}
This will always ignore the owner information. What I'm intending to get is if I have Clientobject and i'm getting it's vehicles, I don't need the resulting owner information of the Vehiclesince i already have the Clientobject. But if i have a Vehicleobject to begin with, I will need it's owner property excluding all the vehicles that Client has.
I'm not sure you are said,so I described all possible features to filter data when the data serializing in the Tests/Examples section.for examples:#JsonIgnore,#JsonIgnoreProperties,#JsonIgnoreType,#JsonView,#JsonFilter and serializing data by mixin/rootType.You could choose one which you like.
Tests/Examples
package com.holi.jackson;
import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonIgnoreType;
import com.fasterxml.jackson.annotation.JsonView;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.Version;
import com.fasterxml.jackson.databind.Module;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.introspect.Annotated;
import com.fasterxml.jackson.databind.introspect.NopAnnotationIntrospector;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.ser.impl.SimpleFilterProvider;
import com.jayway.jsonassert.JsonAssert;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import static com.fasterxml.jackson.annotation.PropertyAccessor.FIELD;
import static com.fasterxml.jackson.databind.SerializationFeature.FAIL_ON_EMPTY_BEANS;
import static com.fasterxml.jackson.databind.ser.impl.SimpleBeanPropertyFilter.serializeAllExcept;
import static org.hamcrest.Matchers.hasSize;
import static org.junit.jupiter.api.Assertions.assertEquals;
/**
* Created by holi on 3/20/17.
*/
public class Jackson2SerializingFilteringTest {
private final User bob = new User("bob", "123456", "bob#example.com");
private final ObjectMapper jackson2 = new ObjectMapper();
#BeforeEach
void configure() {
jackson2.registerModules(configuration());
//write {} for empty bean
jackson2.disable(FAIL_ON_EMPTY_BEANS);
jackson2.setFilterProvider(serializeAll());
jackson2.setVisibility(FIELD, Visibility.ANY);
}
private Module configuration() {
return new SimpleModule() {
#Override
public void setupModule(SetupContext context) {
context.insertAnnotationIntrospector(filterIdAsClassName());
}
};
}
private NopAnnotationIntrospector filterIdAsClassName() {
return new NopAnnotationIntrospector() {
#Override
public Object findFilterId(Annotated ann) {
return ann.getRawType().getName();
}
#Override
public Version version() {
return super.version();
}
};
}
private SimpleFilterProvider serializeAll() {
SimpleFilterProvider filters = new SimpleFilterProvider();
//serialize all if filter not found,rather than throws an exception
filters.setFailOnUnknownId(false);
return filters;
}
#Test
void serializingAll() throws JsonProcessingException {
String json = jackson2.writer().writeValueAsString(bob);
JsonAssert.with(json)
.assertThat("$[*]", hasSize(3))
.assertEquals("name", bob.name)
.assertEquals("password", bob.password)
.assertEquals("mail", bob.mail);
}
#Test
void serializingAllExceptIgnoredProperties() throws JsonProcessingException {
#JsonIgnoreProperties({"name", "version"})
class JSONRoot {
String name = "jackson";
String version = "2.0";
}
JSONRoot root = new JSONRoot();
String json = jackson2.writer().writeValueAsString(root);
assertEquals("{}", json);
}
#Test
void serializingAllExceptIgnoredProperty() throws JsonProcessingException {
class JSONRoot {
String name = "jackson";
#JsonIgnore
String version = "2.0";
}
JSONRoot root = new JSONRoot();
String json = jackson2.writer().writeValueAsString(root);
JsonAssert.with(json)
.assertThat("$[*]", hasSize(1))
.assertEquals("name", root.name);
}
#Test
void serializingAllExceptIgnoredType() throws JsonProcessingException {
#JsonIgnoreType
class Ignored {
}
class JSONRoot {
Ignored ignored = new Ignored();
}
String json = jackson2.writer().writeValueAsString(new JSONRoot());
assertEquals("{}", json);
}
#Test
void serializingMixInAnnotations() throws JsonProcessingException {
jackson2.addMixIn(User.class, ExcludingMail.class);
String json = jackson2.writer().writeValueAsString(bob);
JsonAssert.with(json)
.assertThat("$[*]", hasSize(2))
.assertEquals("name", bob.name)
.assertEquals("password", bob.password);
}
#Test
void serializingUseFiltersToExcludingProperties() throws JsonProcessingException {
String json = jackson2.writer(excludes("password")).writeValueAsString(bob);
JsonAssert.with(json)
.assertThat("$[*]", hasSize(2))
.assertEquals("name", bob.name)
.assertEquals("mail", bob.mail);
}
#Test
void serializingRootTypePropertiesOnly() throws JsonProcessingException {
String json = jackson2.writerFor(Contactable.class).writeValueAsString(bob);
JsonAssert.with(json)
.assertThat("$[*]", hasSize(1))
.assertEquals("mail", bob.mail);
}
#Test
void serializingViewPropertiesOnly() throws JsonProcessingException {
String json = jackson2.writerWithView(Public.class).writeValueAsString(bob);
JsonAssert.with(json)
.assertThat("$[*]", hasSize(2))
.assertEquals("name", bob.name)
.assertEquals("mail", bob.mail);
}
private SimpleFilterProvider excludes(String... propertyNames) {
SimpleFilterProvider filters = serializeAll();
filters.addFilter(User.class.getName(), serializeAllExcept(propertyNames));
return filters;
}
private class User implements Contactable {
final String name;
#JsonView(Privacy.class)
String password;
#JsonView(Public.class)
final String mail;
public User(String name, String password, String mail) {
this.name = name;
this.password = password;
this.mail = mail;
}
public String getMail() {
return mail;
}
}
#interface Public {
}
#interface Privacy {
}
private interface Contactable {
String getMail();
}
#JsonIgnoreProperties("mail")
private class ExcludingMail {
}
}
I want to trim all the form string fields trim automatically (trailing & leading spaces only)
Suppose if I pass FirstName = " robert "
Expected: "robert"
Controller class having following code :
#InitBinder
public void initBinder ( WebDataBinder binder )
{
StringTrimmerEditor stringtrimmer = new StringTrimmerEditor(true);
binder.registerCustomEditor(String.class, stringtrimmer);
}
#RequestMapping(value = "/createuser", method = RequestMethod.POST)
public Boolean createUser(#RequestBody UserAddUpdateParam userAddUpdateParam) throws Exception {
return userFacade.createUser(userAddUpdateParam);
}
when I debug the code, It's coming into #InitBinder but not trimming bean class string fields.
The annotation #InitBinder doesn't work with #RequestBody, you have to use it with the #ModelAttribute annotation
You can find more information in the Spring documentation:
https://docs.spring.io/spring/docs/current/spring-framework-reference/html/mvc.html
To add this feature to all JSON submitted in post and received in RequestBody you can have following WebMvcConfigurer in place.
import java.util.List;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
#Configuration
public class HttpMessageConvertor implements WebMvcConfigurer {
#Override
public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
converters.add(mappingJackson2HttpMessageConverter());
}
#Bean
public MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter() {
MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
ObjectMapper mapper = new ObjectMapper();
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
SimpleModule module = new SimpleModule();
module.addDeserializer(String.class, new StringWithoutSpaceDeserializer(String.class));
mapper.registerModule(module);
converter.setObjectMapper(mapper);
return converter;
}
}
StringWithoutSpaceDeserializer class as :
import java.io.IOException;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
public class StringWithoutSpaceDeserializer extends StdDeserializer<String> {
/**
*
*/
private static final long serialVersionUID = -6972065572263950443L;
protected StringWithoutSpaceDeserializer(Class<String> vc) {
super(vc);
}
#Override
public String deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
return p.getText() != null ? p.getText().trim() : null;
}
}
Try out the below code:
#InitBinder
public void setAllowedFields(WebDataBinder dataBinder) {
dataBinder.registerCustomEditor(String.class, new PropertyEditorSupport() {
#Override
public void setAsText(String text) {
if (text == null) {
return;
}
setValue(text);
}
#Override
public String getAsText() {
Object value = getValue();
return (value != null ? value.trim().toString() : "");
}
});
}
Since Jersey 2.9, it's been possible to create link relations for hypermedia-driven REST APIs through declarative linking.
This code, for example:
#InjectLink(
resource = ItemResource.class,
style = Style.ABSOLUTE,
bindings = #Binding(name = "id", value = "${instance.id}"),
rel = "self"
)
#XmlJavaTypeAdapter(Link.JaxbAdapter.class)
#XmlElement(name="link")
Link self;
...in theory is expected to produce JSON like this:
"link" : {
"rel" : "self",
"href" : "http://localhost/api/resource/1"
}
However, Jersey produces different JSON with a lot of properties that I don't need:
"link" : {
"rel" : "self",
"uri" : "http://localhost/api/resource/1",
"type": null,
"uriBuilder" : null
}
Notice also that instead of href, it uses uri. I looked at Jersey's implementation of the Link object and found JerseyLink.
I want to use Jersey's declarative linking instead of rolling out my own implementation. I ended up using Jackson annotations just to ignore other JerseyLink properties.
#JsonIgnoreProperties({ "uriBuilder", "params", "type", "rels" })
Has anyone used declarative linking with Jersey and had the expected JSON output (e.g., href instead of uri, without extra Jersey properties) without having to use JsonIgnoreProperties or other hacks?
Thanks.
EDIT
I resolved this using an approach which I think is a hack but works well for me and doesn't require the use of a complicated adapter.
I realized that I can actually expose a different object instead of the Link injected by Jersey.
I created a wrapper object named ResourceLink:
public class ResourceLink {
private String rel;
private URI href;
//getters and setters
}
Then in my representation object I have a getter method:
public ResourceLink getLink() {
ResourceLink link = new ResourceLink();
link.setRel(self.getRel());
link.setHref(self.getUri());
return link;
}
So I used Jersey to inject the link but returned a different object in a getter method in my representation object. This would be the property that would be serialized to JSON and not the injected link object because I didn't create a getter method for it.
Invesitigation
Environment: Jersey 2.13 ( all provider versions are also 2.13 ).
Whether you use declarative or programmatic linking, the serialization shouldn't differ. I chose programmatic, just because I can :-)
Test classes:
#XmlRootElement
public class TestClass {
private javax.ws.rs.core.Link link;
public void setLink(Link link) { this.link = link; }
#XmlElement(name = "link")
#XmlJavaTypeAdapter(Link.JaxbAdapter.class)
public Link getLink() { return link; }
}
#Path("/links")
public class LinkResource {
#GET
#Produces(MediaType.APPLICATION_JSON)
public Response getResponse() {
URI uri = URI.create("https://stackoverflow.com/questions/24968448");
Link link = Link.fromUri(uri).rel("stackoverflow").build();
TestClass test = new TestClass();
test.setLink(link);
return Response.ok(test).build();
}
}
#Test
public void testGetIt() {
WebTarget baseTarget = target.path("links");
String json = baseTarget.request().accept(
MediaType.APPLICATION_JSON).get(String.class);
System.out.println(json);
}
Results with different Providers (with no extra configurations)
jersey-media-moxy
Dependency
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-moxy</artifactId>
</dependency>
Result (weird)
{
"link": "javax.ws.rs.core.Link$JaxbLink#cce17d1b"
}
jersey-media-json-jackson
Dependency
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-json-jackson</artifactId>
</dependency>
Result (close, but what's with the params?)
{
"link": {
"params": {
"rel": "stackoverflow"
},
"href": "https://stackoverflow.com/questions/24968448"
}
}
jackson-jaxrs-json-provider
Dependency
<dependency>
<groupId>com.fasterxml.jackson.jaxrs</groupId>
<artifactId>jackson-jaxrs-json-provider</artifactId>
<version>2.4.0</version>
</dependency>
Result (Two different results, with two different JSON providers)
resourceConfig.register(JacksonJsonProvider.class);
{
"link": {
"uri": "https://stackoverflow.com/questions/24968448",
"params": {
"rel": "stackoverflow"
},
"type": null,
"uriBuilder": {
"absolute": true
},
"rels": ["stackoverflow"],
"title": null,
"rel": "stackoverflow"
}
}
resourceConfig.register(JacksonJaxbJsonProvider.class);
{
"link": {
"params": {
"rel": "stackoverflow"
},
"href": "https://stackoverflow.com/questions/24968448"
}
}
My Conclusions
We are annotating the field with #XmlJavaTypeAdapter(Link.JaxbAdapter.class). Let look at a snippet of this adapter
public static class JaxbAdapter extends XmlAdapter<JaxbLink, Link> {...}
So from Link, we are being marshalled to JaxbLink
public static class JaxbLink {
private URI uri;
private Map<QName, Object> params;
...
}
jersey-media-moxy
Seems to be a bug... See below in solutions.
The others
The other two are dependent on jackson-module-jaxb-annotations to handle marshalling using JAXB annotations. jersey-media-json-jackson will automatically register the required JaxbAnnotationModule. For jackson-jaxrs-json-provider, using JacksonJsonProvider will not support JAXB annotations (without confgiruation), and using JacksonJsonJaxbProvider will give us the JAXB annotation support.
So if we have JAXB annotation support, we will get marshalled to JaxbLink, which will give this result
{
"link": {
"params": {
"rel": "stackoverflow"
},
"href": "https://stackoverflow.com/questions/24968448"
}
}
The ways we can get the result with all the unwanted properties, is to 1), use the jackson-jaxrs-json-provider's JacksonJsonProvider or 2), create a ContextResolver for ObjectMapper where we don't register the JaxbAnnotationModule. You seem to be doing one of those.
Solutions
The above still doesn't get us where we want to get to (i.e. no params).
For jersey-media-json-jackson and jackson-jaxrs-json-provider...
...which use Jackson, the only thing I can think of at this point is to create a custom serializer
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
import java.io.IOException;
import javax.ws.rs.core.Link;
public class LinkSerializer extends JsonSerializer<Link>{
#Override
public void serialize(Link link, JsonGenerator jg, SerializerProvider sp)
throws IOException, JsonProcessingException {
jg.writeStartObject();
jg.writeStringField("rel", link.getRel());
jg.writeStringField("href", link.getUri().toString());
jg.writeEndObject();
}
}
Then create a ContextResolver for the ObjectMapper, where we register the serializer
#Provider
public class ObjectMapperContextResolver
implements ContextResolver<ObjectMapper> {
private final ObjectMapper mapper;
public ObjectMapperContextResolver() {
mapper = new ObjectMapper();
SimpleModule simpleModule = new SimpleModule();
simpleModule.addSerializer(Link.class, new LinkSerializer());
mapper.registerModule(simpleModule);
}
#Override
public ObjectMapper getContext(Class<?> type) {
return mapper;
}
}
This is the result
{
"link": {
"rel": "stackoverflow",
"href": "https://stackoverflow.com/questions/24968448"
}
}
With jersey-media-moxy, it appears there's a Bug with missing setters in the JaxbLink class, so the marshalling reverts to calling toString, which is what's shown above. A work around, as proposed here by Garard Davidson, is just to create another adapter
import java.net.URI;
import java.util.HashMap;
import java.util.Map;
import javax.ws.rs.core.Link;
import javax.xml.bind.annotation.XmlAnyAttribute;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.adapters.XmlAdapter;
import javax.xml.namespace.QName;
public class LinkAdapter
extends XmlAdapter<LinkJaxb, Link> {
public LinkAdapter() {
}
public Link unmarshal(LinkJaxb p1) {
Link.Builder builder = Link.fromUri(p1.getUri());
for (Map.Entry<QName, Object> entry : p1.getParams().entrySet()) {
builder.param(entry.getKey().getLocalPart(), entry.getValue().toString());
}
return builder.build();
}
public LinkJaxb marshal(Link p1) {
Map<QName, Object> params = new HashMap<>();
for (Map.Entry<String,String> entry : p1.getParams().entrySet()) {
params.put(new QName("", entry.getKey()), entry.getValue());
}
return new LinkJaxb(p1.getUri(), params);
}
}
class LinkJaxb {
private URI uri;
private Map<QName, Object> params;
public LinkJaxb() {
this (null, null);
}
public LinkJaxb(URI uri) {
this(uri, null);
}
public LinkJaxb(URI uri, Map<QName, Object> map) {
this.uri = uri;
this.params = map!=null ? map : new HashMap<QName, Object>();
}
#XmlAttribute(name = "href")
public URI getUri() {
return uri;
}
#XmlAnyAttribute
public Map<QName, Object> getParams() {
return params;
}
public void setUri(URI uri) {
this.uri = uri;
}
public void setParams(Map<QName, Object> params) {
this.params = params;
}
}
Using this adapter instead
#XmlElement(name = "link")
#XmlJavaTypeAdapter(LinkAdapter.class)
private Link link;
will give us the desired output
{
"link": {
"href": "https://stackoverflow.com/questions/24968448",
"rel": "stackoverflow"
}
}
UPDATE
Now that I think about it, the LinkAdapter would work with the Jackson provider also. No need to create a Jackson Serializer/Deserializer. The Jackson module should already support the JAXB annotations out the box, given the JacksonFeature is enabled. The examples above show using the JAXB/JSON providers separately, but given just the JacksonFeature is enabled, the JAXB version of the provider should be used. This may actually be the more preferred solution. No need to create an ContextResolvers for the ObjectMapper :-D
It's also possible to declare the annotation at the package level, as seen here
I'd like to share with my solution for serialising/deserialising Link objects using with Jackson and the mix-in annotations.
LinkMixin:
#JsonAutoDetect(
fieldVisibility = JsonAutoDetect.Visibility.NONE,
getterVisibility = JsonAutoDetect.Visibility.NONE,
isGetterVisibility = JsonAutoDetect.Visibility.NONE)
#JsonDeserialize(using = LinkMixin.LinkDeserializer.class)
public abstract class LinkMixin extends Link {
private static final String HREF = "href";
#JsonProperty(HREF)
#Override
public abstract URI getUri();
#JsonAnyGetter
public abstract Map<String, String> getParams();
public static class LinkDeserializer extends JsonDeserializer<Link> {
#Override
public Link deserialize(
final JsonParser p,
final DeserializationContext ctxt) throws IOException {
final Map<String, String> params = p.readValueAs(
new TypeReference<Map<String, String>>() {});
if (params == null) {
return null;
}
final String uri = params.remove(HREF);
if (uri == null) {
return null;
}
final Builder builder = Link.fromUri(uri);
params.forEach(builder::param);
return builder.build();
}
}
}
Example:
final ObjectMapper mapper = new ObjectMapper();
mapper.addMixIn(Link.class, LinkMixin.class);
final Link link = Link.fromUri("http://example.com")
.rel("self")
.title("xxx")
.param("custom", "my")
.build();
final String json = mapper
.writerWithDefaultPrettyPrinter()
.writeValueAsString(Collections.singleton(link));
System.out.println(json);
final List<Link> o = mapper.readValue(json, new TypeReference<List<Link>>() {});
System.out.println(o);
Output:
[ {
"href" : "http://example.com",
"rel" : "self",
"title" : "xxx",
"custom" : "my"
} ]
[<http://example.com>; rel="self"; title="xxx"; custom="my"]
Using the suggested update solution I was still getting the rel part inside the params map.
I have made some changes in the Link adapter class
public class LinkAdapter
extends XmlAdapter<LinkJaxb, Link> {
public LinkAdapter() {
}
public Link unmarshal(LinkJaxb p1) {
Link.Builder builder = Link.fromUri(p1.getUri());
return builder.build();
}
public LinkJaxb marshal(Link p1) {
return new LinkJaxb(p1.getUri(), p1.getRel());
}
}
class LinkJaxb {
private URI uri;
private String rel;
public LinkJaxb() {
this (null, null);
}
public LinkJaxb(URI uri) {
this(uri, null);
}
public LinkJaxb(URI uri,String rel) {
this.uri = uri;
this.rel = rel;
}
#XmlAttribute(name = "href")
public URI getUri() {
return uri;
}
#XmlAttribute(name = "rel")
public String getRel(){return rel;}
public void setUri(URI uri) {
this.uri = uri;
}
}
It now holds only the two params which are needed (rel,href)
I did not really understand when do I need to unmarshal a Jaxb link to a Link.
What mattered to me was the Link to Jaxb link marshaling.
Thank You, #peeskillet and #Nir Sivan, for your answers. But I was able to make it work without using the LinkAdapter or ContextResolver<ObjectMapper>.
I just added a instance variable of the custom Link type (here ResourceLink which is analogous to your LinkJaxb) to my entity class as a #Transient property and after that Jackson configuration automatically included that attribute in the Response JSON
Resource Link - Class
import javax.xml.bind.annotation.XmlAttribute;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonInclude.Include;
#JsonInclude(Include.NON_EMPTY)
public class ResourceLink {
private String uri;
private String rel;
public ResourceLink() {
this (null, null);
}
public ResourceLink(String uri) {
this(uri, null);
}
public ResourceLink(String uri,String rel) {
this.uri = uri;
this.rel = rel;
}
#XmlAttribute(name = "href")
public String getUri() {
return uri;
}
#XmlAttribute(name = "rel")
public String getRel(){return rel;}
public void setUri(String uri) {
this.uri = uri;
}
}
Entity Class
package com.bts.entities;
import java.util.ArrayList;
import java.util.List;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Transient;
import com.bts.rs.root.util.ResourceLink;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonInclude.Include;
#Entity
#Table(name="cities")
#JsonInclude(Include.NON_EMPTY)
public class City {
#Id
#Column(name="city_id")
private Integer cityId;
#Column(name="name")
private String name;
#Column(name="status")
private int status;
#Column(name="del_status")
private int delStatus;
#Transient
List<ResourceLink> links = new ArrayList<ResourceLink>();
// private
public City () {
}
public City (Integer id, String name) {
this.cityId = id;
this.name = name;
this.status = 0;
this.delStatus = 0;
}
// getters and setters for Non-transient properties
// Below is the getter for lInks transient attribute
public List<ResourceLink> getLinks(){
return this.links;
}
// a method to add links - need not be a setter necessarily
public void addResourceLink (String uri,String rel) {
this.links.add(new ResourceLink(uri, rel));
}
}
Jersy Resource Provider
#GET
#Path("/karanchadha")
#Produces({MediaType.APPLICATION_JSON})
#Transactional
public Response savePayment() {
City c1 = new City();
c1.setCityId(11);
c1.setName("Jamshedpur");
c1.addResourceLink("http://www.test.com/home", "self");
c1.addResourceLink("http://www.test.com/2", "parent");
return Response.status(201).entity(c1).build();
}
First dependencies :
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-json-jackson</artifactId>
<version>2.34</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.ext</groupId>
<artifactId>jersey-declarative-linking</artifactId>
<version>2.34</version>
</dependency>
Second - config class:
package app.rest.config;
import javax.ws.rs.ApplicationPath;
import org.glassfish.jersey.jackson.internal.jackson.jaxrs.json.JacksonJaxbJsonProvider;
import org.glassfish.jersey.linking.DeclarativeLinkingFeature;
import org.glassfish.jersey.server.ResourceConfig;
#ApplicationPath(value = "rest")
public class RestApplicationConfig extends ResourceConfig{
public RestApplicationConfig() {
register(JacksonJaxbJsonProvider.class);
register(DeclarativeLinkingFeature.class);
packages("app.rest.controllers");
}
}
Third - create adapter class
package app.rest.config;
import javax.json.Json;
import javax.json.JsonObject;
import javax.json.bind.adapter.JsonbAdapter;
import javax.ws.rs.core.Link;
import javax.ws.rs.core.UriBuilder;
public class CustomJsonAdapter implements JsonbAdapter<Link, JsonObject> {
#Override
public JsonObject adaptToJson(Link link) throws Exception {
StringBuilder builder = new StringBuilder();
builder.append("http://");
builder.append(link.getUri().getHost());
builder.append(":");
builder.append(link.getUri().getPort());
builder.append(link.getUri().getRawPath());
return Json.createObjectBuilder().add("href", builder.toString()).add("rel", link.getRel()).build();
}
#Override
public Link adaptFromJson(JsonObject json) throws Exception {
Link link = Link.fromUriBuilder(UriBuilder.fromUri(json.getString("href"))).rel(json.getString("rel")).build();
return link;
}
}
Forth - register JsonbConfig with custom adapter class from Link class to Json
package app.rest.config;
import javax.json.bind.Jsonb;
import javax.json.bind.JsonbBuilder;
import javax.json.bind.JsonbConfig;
import javax.ws.rs.ext.ContextResolver;
import javax.ws.rs.ext.Provider;
#Provider
public class AppJsonConfig implements ContextResolver<Jsonb> {
#Override
public Jsonb getContext(Class<?> type) {
JsonbConfig jsonbConfig = new JsonbConfig();
jsonbConfig.withAdapters(new CustomJsonAdapter());
return JsonbBuilder.create(jsonbConfig);
}
}
Fifth : create the model with Link and #InjectLink annotation
package app.rest.model;
import java.io.Serializable;
import java.util.Objects;
import javax.json.bind.annotation.JsonbTypeAdapter;
import javax.ws.rs.core.Link;
import javax.xml.bind.annotation.XmlRootElement;
import org.glassfish.jersey.linking.Binding;
import org.glassfish.jersey.linking.InjectLink;
import org.glassfish.jersey.linking.InjectLink.Style;
import app.rest.config.CustomJsonAdapter;
import app.rest.controllers.RestController;
#XmlRootElement
public class StudentResource implements Serializable{
private static final long serialVersionUID = 1L;
private Long id;
private String name;
private String surname;
#InjectLink(resource = RestController.class,
style = Style.ABSOLUTE,
rel = "self",
method = "getStudentById",
bindings = #Binding(name = "id", value = "${instance.id}"))
#JsonbTypeAdapter(value = CustomJsonAdapter.class)
private Link link;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSurname() {
return surname;
}
public void setSurname(String surname) {
this.surname = surname;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public Link getLink() {
return link;
}
public void setLink(Link link) {
this.link = link;
}
#Override
public int hashCode() {
return Objects.hash(name, surname);
}
#Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
StudentResource other = (StudentResource) obj;
return Objects.equals(name, other.name) && Objects.equals(surname, other.surname);
}
}
And at the end rest controller
package app.rest.controllers;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.GenericEntity;
import javax.ws.rs.core.Link;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.UriInfo;
import app.rest.model.*;
#Path(value = "student")
public class RestController {
#Context
private UriInfo uriInfo;
private final ArrayList<StudentResource> students = new ArrayList<>();
public RestController() {
StudentResource s1 = new StudentResource();
s1.setId(1L);
s1.setName("test1");
s1.setSurname("surTest1");
students.add(s1);
StudentResource s2 = new StudentResource();
s2.setId(2L);
s2.setName("new_St");
s2.setSurname("surNew");
students.add(s2);
}
#GET
#Produces(MediaType.APPLICATION_JSON)
public Response getAllStudents() throws URISyntaxException{
Link link = Link.fromUriBuilder(uriInfo.getAbsolutePathBuilder()).rel("self").type("GET").build();
GenericEntity<List<StudentResource>> studentsEntities = new GenericEntity<List<StudentResource>>(students) {};
return Response.status(Response.Status.OK).entity(studentsEntities).links(link).build();
}
#GET
#Path(value = "/{id}")
#Produces(MediaType.APPLICATION_JSON)
public Response getStudentById(#PathParam(value = "id") Long id ) {
Iterator<StudentResource> iterator = students.iterator();
StudentResource studentById= null;
while (iterator.hasNext()) {
StudentResource next = iterator.next();
if(next.getId().equals(id)) {
studentById = next;
break;
}
}
if(null!=studentById) return Response.status(Response.Status.OK).entity(studentById).build();
else return Response.status(Response.Status.NO_CONTENT).build();
}
}
Deployed and tested on Payara 5.201
Produces : get http://localhost:8080/sampleappee/rest/student/1
{"id":1,"link":{"href":"http://localhost:8080/sampleappee/rest/student/1","rel":"self"},"name":"test1","surname":"surTest1"}