JAXRS client - Deserialization Issue with Pojo - json

Question

Helo Everyone. I am new to jersey and Jackson and finding it really difficult to deserialize a JSOn response from my REST service on client side. I am pretty sure that I am still not grasping the Object mapper and JSON provider APIs that well. Any help or guidance is appreciated in advance. Here is my source code.
Source Code
POJO Class
#XmlRootElement(name = "user")
public class User implements Serializable{
private String firstName;
private String lastName;
private String email;
private String userID;
public User() {
}
public User(String firstName, String lastName, String email, String userID) {
this.firstName = firstName;
this.lastName = lastName;
this.email = email;
this.userID = userID;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getUserID() {
return userID;
}
public void setUserID(String userID) {
this.userID = userID;
}
}
Client Code
package com.example.service.client;
import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.WebTarget;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import org.glassfish.jersey.jackson.JacksonFeature;
import com.example.service.bean.User;
import com.example.service.client.mapper.MyMessageBodyReader;
import com.example.service.client.mapper.MyObjectMapperProvider;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider;
import com.fasterxml.jackson.jaxrs.json.JacksonJsonProvider;
public class GetJSONResponse {
public static void main(String[] args) {
// TODO Auto-generated method stub
JacksonJaxbJsonProvider provider1 = new JacksonJaxbJsonProvider();
Client c = ClientBuilder.newClient()register(provider1);//.register(mapper);
WebTarget target = c.target("http://localhost:8080/RestfulWebserviceExample").path("/jaxrs/user/Nishit");
Response resp = target.request(MediaType.APPLICATION_JSON).get();
System.out.println(resp.getStatus());
String user1 = resp.readEntity(String.class);
System.out.println(user1);
User user = target.request(MediaType.APPLICATION_JSON).get(User.class);
System.out.println("User : " + user.getUserID());
}
}
`
The first 2 sysout generates an output as
200
{"user":{"firstName":"Nishit","lastName":"Ladha","email":"ladha#us.ibm.com","userID":"nishiz"}}
But when i tries to directly get the User object from response, I get an error as
Exception in thread "main" javax.ws.rs.client.ResponseProcessingException: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "user" (class com.example.service.bean.User), not marked as ignorable (4 known properties: "lastName", "firstName", "email", "userID"])
at [Source: org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$UnCloseableInputStream#10163d6; line: 1, column: 10] (through reference chain: com.example.service.bean.User["user"])
at org.glassfish.jersey.client.JerseyInvocation.translate(JerseyInvocation.java:806)
at org.glassfish.jersey.client.JerseyInvocation.access$700(JerseyInvocation.java:92)
at org.glassfish.jersey.client.JerseyInvocation$2.call(JerseyInvocation.java:700)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:228)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:444)
at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:696)
at org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:420)
at org.glassfish.jersey.client.JerseyInvocation$Builder.get(JerseyInvocation.java:316)
at com.example.service.client.GetJSONResponse.main(GetJSONResponse.java:40)
Caused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "user" (class com.example.service.bean.User), not marked as ignorable (4 known properties: "lastName", "firstName", "email", "userID"])
It will be really kind if anyone of you can guide me how to resolve this.
I am not using Maven as I first wanted to try without Maven
I am not sure why my rest service is wrapping the response. Here is the code :
Service Method
#GET
#Path("/{username}")
#Produces(MediaType.APPLICATION_JSON)
public User helloWorld(#PathParam("username") String name){
User user = new User();
user.setFirstName("Nishit");
user.setLastName("Ladha");
user.setUserID("nishiz");
user.setEmail("ladha#us.ibm.com");
return user;
}
Web.xml##
<servlet>
<description>JAX-RS Tools Generated - Do not modify</description>
<servlet-name>JAX-RS Servlet</servlet-name>
<servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
<init-param>
<param-name>jersey.config.server.provider.packages</param-name>
<param-value>
com.example.service,
com.fasterxml.jackson.jaxrs.json
</param-value>
</init-param>
<init-param>
<param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
<param-value>false</param-value>
</init-param>
<load-on-startup>1</load-on-startup>

Answer 1

Man, look, you are trying to bind unexistent field User.
If you want to properly parse this json
{"user":{"firstName":"Nishit","lastName":"Ladha","email":"ladha#us.ibm.com","userID":"nishiz"}}
You need to have similar to this class
public class UserWrapper implements Serializable{
private User user;
// Constructors
// Getters, and setters
// HashCode and equals
}
Then this client code will work:
public class GetJSONResponse {
public static void main(String[] args) {
// TODO Auto-generated method stub
JacksonJaxbJsonProvider provider1 = new JacksonJaxbJsonProvider();
Client c = ClientBuilder.newClient()register(provider1);//.register(mapper);
WebTarget target = c.target("http://localhost:8080/RestfulWebserviceExample").path("/jaxrs/user/Nishit");
Response resp = target.request(MediaType.APPLICATION_JSON).get();
System.out.println(resp.getStatus());
String user1 = resp.readEntity(String.class);
System.out.println(user1);
UserWrapper userWrapper = target.request(MediaType.APPLICATION_JSON).get(UserWrapper.class);
}
}
If you have any questions - just ask.Hope your code will work.