I'm trying to use the primefaces LazyDataModel for a tabelaric view in JSF, the problem is that I'm unable to inject anything into the class. I always get null fot the injected object.
For example I'm injecting
#PersistenceContext(unitName = "domainDS")
private EntityManager em;
or an EJB
#EJB
OrganizationHandler orgHandler;
but I get null for both of them.
The whole lazy datamodel class
import java.io.Serializable;
import java.util.List;
import java.util.Map;
import javax.ejb.EJB;
import javax.ejb.Stateless;
import javax.inject.Named;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import org.primefaces.model.LazyDataModel;
import org.primefaces.model.SortOrder;
import si.arctur.controller.OrganizationHandler;
import si.arctur.model.Organization;
#Named
#Stateless
public class LazyOrganizationDataModel extends LazyDataModel<Organization> implements Serializable {
private static final long serialVersionUID = 675394666656356734L;
#PersistenceContext(unitName = "domainDS")
private EntityManager em;
#EJB
OrganizationHandler orgHandler;
public LazyOrganizationDataModel() {
super();
}
#SuppressWarnings("unchecked")
#Override
public List<Organization> load(int first, int pageSize, String sortField, SortOrder sortOrder, Map<String,String> filters) {
List<Organization> data = orgHandler.selectOrganizatoins(first, pageSize, sortField, "asc", filters);
//row count
this.setRowCount(data.size());
return data;
}
}
You're probably not injecting the lazy data model. Based on their examples, they show someone instantiating it. You should instead get a reference via CDI to the bean.
Related
i am using keycloak and spring to get the user list in a rest service, however the rest return the html instead of json data.
here is the service.
import org.keycloak.representations.idm.UserRepresentation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Service;
#Service
public class UserServiceImpl implements UserService{
#Autowired
KeycloakInstance keycloakInstance;
public List<UserRepresentation> loadUsers(String realm) {
return keycloakInstance.getInstance()
.realm(realm)
.users()
.list();
}
}
here is the controller.
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.*;
import org.keycloak.representations.idm.UserRepresentation;
import java.util.List;
#RestController
#RequestMapping("/api/admin/users")
public class UserController {
#Autowired
private UserService userService;
#GetMapping(value = "", produces="application/json")
public List<UserRepresentation> loadUsers() {
String realm = "abc";
return userService.loadUsers(realm);
}
}
any idea how to fix this?
You would need to add the path to #GetMapping, this should work
#ResponseBody
#GetMapping(value = "/api/admin/users", produces="application/json")
public List<UserRepresentation> loadUsers() {
String realm = "abc";
return userService.loadUsers(realm);
}
or using this way
#GetMapping (value = "/api/admin/users", produces = MediaType.APPLICATION_JSON_VALUE)
As #ConstantinKonstantinidis commented, add to RequestMapping produces JSON to apply to your method (and all methods):
#RequestMapping(value = "/api/admin/users", produces = MediaType.APPLICATION_JSON_VALUE
Supported at the type level as well as at the method level
Another option is to add the path to #GetMapping ,e.g.
#RequestMapping("/api/admin")
public class UserController {
#GetMapping(value = "/users", produces="application/json")
I am making simple program that have to get some info from OpenWeatherMap API and save it in MySQL database:
package com.example.restTemplate;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
#SpringBootApplication
public class RestTemplateApplication {
public static void main(String[] args) {
SpringApplication.run(RestTemplateApplication.class, args);
}
#Bean
public RestTemplate getRestTemplate() {
return new RestTemplate();
}
}
package com.example.restTemplate.Model;
import lombok.*;
import javax.persistence.Entity;
import javax.persistence.Id;
#NoArgsConstructor
#AllArgsConstructor
#Entity
#javax.persistence.Table(name="Weather")
#Getter
#Setter
#ToString
public class WeatherScore {
#Id
private int id;
private String city;
private double temperature;
private int pressure;
private long currentDate;
}
package com.example.restTemplate.Controller;
import com.example.restTemplate.Model.WeatherScore;
import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;
#Repository
public interface WeatherCRUDRepository
extends CrudRepository<WeatherScore, Long> {
WeatherScore save (WeatherScore score);
}
package com.example.restTemplate.Controller;
import com.example.restTemplate.Model.WeatherScore;
import org.springframework.context.ApplicationContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import java.util.Arrays;
import java.util.Random;
#RestController
public class ConsumeWebService {
#Autowired
RestTemplate restTemplate;
WeatherCRUDRepository repository;
ApplicationContext context;
#RequestMapping(value = "/weather")
public void printWeather() {
HttpHeaders headers = new HttpHeaders();
headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
HttpEntity<String> entity = new HttpEntity<String>(headers);
String text = restTemplate.exchange("http://api.openweathermap.org/data/2.5/weather?q=London,uk&APPID=mykey",
HttpMethod.GET, entity, String.class).getBody();
int pressureStartIndex = text.indexOf("pressure")+10;
int pressureEndIndex = text.indexOf(",", pressureStartIndex);
int tempStartIndex = text.indexOf("temp")+6;
int tempEndIndex = text.indexOf(",", tempStartIndex);
int pressure = Integer.parseInt(text.substring(pressureStartIndex, pressureEndIndex));
double temperature = Double.parseDouble(text.substring(tempStartIndex, tempEndIndex));
WeatherScore score = new WeatherScore();
score.setCity("London");
score.setPressure(pressure);
score.setTemperature(temperature);
Random generator = new Random();
score.setId(generator.nextInt(1000));
score.setCurrentDate(System.currentTimeMillis());
WeatherCRUDRepository repo = context.getBean(WeatherCRUDRepository.class);
repository.save(score);
}
}
When i tap http://localhost:8080/weather i get an error:
Cannot invoke
"org.springframework.context.ApplicationContext.getBean(java.lang.Class)"
because "this.context" is null
Blockquote
How i could fix that?
You have to autowire all the beans within controller, like so:
#Autowired
RestTemplate restTemplate;
#Autowired
WeatherCRUDRepository repository;
#Autowired
ApplicationContext context;
I am trying to build Spring-boot CRUD application with Hibernate and REST -API.However when I try to run the app everything is working fine but console is displaying the following error
java.lang.NullPointerException: null
at io.javabrains.EmployerController.getAllEmployers(EmployerController.java:20) ~[classes/:na]
I tried to change the value however it didnt work
EmployerService.java
package io.javabrains;
import java.util.ArrayList;
import java.util.List;
import org.springframework.stereotype.Service;
import io.javabrains.Entity.Employer;
#Service
public class EmployerService {
private Repository repository;
public List<Employer>getAllEmployers(){
List<Employer>employers = new ArrayList<>();
repository.findAll()
.forEach(employers::add);
return employers;
}
public void addEmployer(Employer employer) {
repository.save(employer);
}
}
EmployerController.java
package io.javabrains;
import java.util.List;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import io.javabrains.Entity.Employer;
#RestController
public class EmployerController {
private EmployerService service;
#RequestMapping("/employer")
public List<Employer>getAllEmployers()
{
return service.getAllEmployers();
}
/*
* #RequestMapping("/employer/{id}") public Employer getEmployer(#PathVariable
* int id) { return service.getEmployer(id); }
*/
#RequestMapping(method=RequestMethod.POST,value="/employer/create")
public void addEmployer(#RequestBody Employer employer) {
service.addEmployer(employer);
}
}
....
On the analysis of the code snippet given, the null pointer exception occurred since your code doesn't ask the spring dependency injector to inject EmployerService as a dependency to EmployerController, so it doesn't inject the EmployerService bean class to the reference private EmployerService employerService; thus it is null in EmployerController. You can ask Spring Dependency Injector to inject dependency by adding #Autowire annotation private EmployerService service; refence in EmployerController
Update your EmployerService to the following will work
package io.javabrains;
import java.util.List;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import io.javabrains.Entity.Employer;
#RestController
public class EmployerController {
//UPDATE : Autowiring
#Autowired
private EmployerService employerService;
#RequestMapping("/employer")
public List < Employer > getAllEmployers() {
return service.getAllEmployers();
}
/*
* #RequestMapping("/employer/{id}") public Employer getEmployer(#PathVariable
* int id) { return employerService.getEmployer(id); }
*/
#RequestMapping(method = RequestMethod.POST, value = "/employer/create")
public void addEmployer(#RequestBody Employer employer) {
employerService.addEmployer(employer);
}
}
And Also, the same issue would occur in Service when trying to access repository.
Update EmployeeService.java code include #autorwired logic:
package io.javabrains;
import java.util.ArrayList;
import java.util.List;
import org.springframework.stereotype.Service;
import org.springframework.beans.factory.annotation.Autowired;
import io.javabrains.Entity.Employer;
#Service
public class EmployerService {
#Autowired
private Repository repository;
public List<Employer>getAllEmployers(){
List<Employer>employers = new ArrayList<>();
repository.findAll()
.forEach(employers::add);
return employers;
}
public void addEmployer(Employer employer) {
repository.save(employer);
}
}
private EmployerService employerService;
This mean you have created a reference variable of EmployerService not an object of EmployerService. Which can be done by using a new keyword. But as you know Spring Container uses DI(Dependency Injection) to manage a beans(an object, in above case object of EmployerService). So the object instantiation and whole lifecycle of an object is managed by the spring. For this we have to tell that the this object should be managed by the spring which is done by using #Autowired annotation.
You need to get object of repository before using, for that add #Autowired on
private Repository repository;
in your EmployerService class.
#Autowired is definitely the solution.
But your service class, if you ask for your REPOSITORY, you should put there too.
So in my problem, the solution was
#Autowired
private ProductService productService;
And
#Autowired
ProductRepository productRepository;
there was a line inside a method that was throwing this NullpointerException then later on I put that line in the if statement and it worked for me seamlessly.
example:
if (user != null) { application.setEmailaddress(user.getEmail());}
I am using Spring 4 and Hibernate 4. I am using java jpa to use hibernate. I want to load few data lazily. And I have also configured Jackson mapper to convert my java object to json and vice versa. But it's throwing exception while converting the java to json. I have created custom object mapper but still it's not working.
Please see the following classes and see what I am missing here
I am using annotations. Hibernate configuration file:
MvcConfiguration.java
package com.ampdev.platform.module.common.config;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import com.ampdev.platform.framework.dataaccess.config.HibernateAwareObjectMapper;
import com.ampdev.platform.framework.rest.security.AuthenticationService;
import com.ampdev.platform.framework.rest.security.AuthenticationServiceDefault;
import com.ampdev.platform.module.user.util.EncryptionUtil;
import com.fasterxml.jackson.databind.ObjectMapper;
#Configuration
#ComponentScan(basePackages = "com.ampdev")
#EnableWebMvc
#EnableTransactionManagement
public class MvcConfiguration extends WebMvcConfigurerAdapter
{
#Bean
public ViewResolver getViewResolver()
{
InternalResourceViewResolver resolver = new InternalResourceViewResolver();
resolver.setPrefix("/WEB-INF/views/");
resolver.setSuffix(".jsp");
return resolver;
}
#Override
public void addResourceHandlers(ResourceHandlerRegistry registry)
{
registry.addResourceHandler("/resources/**").addResourceLocations("/resources/");
}
#Autowired
#Bean(name = "authenticationService")
public AuthenticationService getAuthencticaionService()
{
return new AuthenticationServiceDefault();
}
#Autowired
#Bean(name = "passwordEncoder")
public PasswordEncoder getPasswordEncoder()
{
return new BCryptPasswordEncoder();
}
#Autowired
#Bean(name = "encrypyionUtil")
public EncryptionUtil getEncryptionUtil(PasswordEncoder passwordEncoder)
{
return new EncryptionUtil(passwordEncoder);
}
#Autowired
#Bean(name = "objectMapper")
public ObjectMapper getObjectMapper()
{
return new HibernateAwareObjectMapper();
}
#Autowired
#Bean(name = "jsonMessageConverter")
public MappingJackson2HttpMessageConverter getMessageConvertor()
{
return new MappingJackson2HttpMessageConverter();
}
#Autowired
private ObjectMapper objectMapper;
#Autowired
private MappingJackson2HttpMessageConverter jsonMessageConverter;
#Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters)
{
jsonMessageConverter.setObjectMapper(objectMapper);
converters.add(jsonMessageConverter);
}
}
I have created a custom object mapper to include Hibernate4Module
HibernateAwareObjectMapper.java
package com.ampdev.platform.framework.dataaccess.config;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.hibernate4.Hibernate4Module;
public class HibernateAwareObjectMapper extends ObjectMapper
{
/**
*
*/
private static final long serialVersionUID = -4013528320937607847L;
public HibernateAwareObjectMapper()
{
Hibernate4Module hibernateModule = new Hibernate4Module();
registerModule(hibernateModule);
}
}
Here is my Data object in which I am using the lazy loading:
UserMovieReviewData .java
package com.ampdev.platform.module.movie.review.user.dataobject;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.OneToOne;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import com.ampdev.platform.module.common.dataobject.PersistedDataObject;
import com.ampdev.platform.module.movie.dataobject.MovieData;
import com.ampdev.platform.module.movie.review.constants.ReviewConstants;
import com.ampdev.platform.module.user.dataobject.UserData;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonInclude.Include;
#Entity
#Table(name = "movie_review_user")
#JsonInclude(Include.NON_NULL)
public class UserMovieReviewData extends PersistedDataObject
{
/**
*
*/
private static final long serialVersionUID = -5644749600929596177L;
#Id
#GeneratedValue
#Column(name = "review_id")
private long id;
#OneToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "movie_id")
private MovieData movieData;
#OneToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "user_id")
private UserData userData;
#Column(name = "rating")
private int rating;
#Column(name = "title")
private String title;
#Column(name = "review")
private String review;
#Column(name = "create_date")
#Temporal(TemporalType.TIMESTAMP)
private Date createDate;
#Column(name = "update_date")
#Temporal(TemporalType.TIMESTAMP)
private Date updateDate;
#Override
public long getId()
{
return id;
}
public void setId(long id)
{
this.id = id;
}
public MovieData getMovieData()
{
return movieData;
}
public void setMovieData(MovieData movieData)
{
this.movieData = movieData;
}
public UserData getUserData()
{
return userData;
}
public void setUserData(UserData userData)
{
this.userData = userData;
}
public int getRating()
{
return rating;
}
public void setRating(int rating)
{
this.rating = rating;
}
public String getTitle()
{
return title;
}
public void setTitle(String title)
{
this.title = title;
}
public String getReview()
{
return review;
}
public void setReview(String review)
{
this.review = review;
}
public Date getCreateDate()
{
return createDate;
}
public void setCreateDate(Date createDate)
{
this.createDate = createDate;
}
public Date getUpdateDate()
{
return updateDate;
}
public void setUpdateDate(Date updateDate)
{
this.updateDate = updateDate;
}
}
Here is my web service resource which I am using as rest resource:
ReviewResource.java
package com.ampdev.platform.module.movie.review.resource;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.context.annotation.Scope;
import org.springframework.http.RequestEntity;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import com.ampdev.platform.framework.rest.BaseExecutor;
import com.ampdev.platform.framework.rest.RestBaseResource;
import com.ampdev.platform.module.common.constants.URIConstants;
import com.ampdev.platform.module.movie.review.constants.ReviewConstants;
import com.ampdev.platform.module.movie.review.user.dataobject.UserMovieReviewData;
#Controller
#RequestMapping(value = "/ws/movie/review")
#Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public class ReviewResource extends RestBaseResource
{
#Autowired
private BaseExecutor<UserMovieReviewData, UserMovieReviewData> createMovieReviewExecutor;
#Autowired
private BaseExecutor<String, List<UserMovieReviewData>> getMovieReviewExecutor;
#RequestMapping(value = ReviewConstants.ADD, method = RequestMethod.POST)
public ResponseEntity<UserMovieReviewData> createMovieReview(
#RequestParam(value = ReviewConstants.TYPE, required = true) String type,
RequestEntity<UserMovieReviewData> requestEntity)
{
createMovieReviewExecutor.setAttribute(ReviewConstants.TYPE, type);
return performTask(requestEntity, createMovieReviewExecutor);
}
#RequestMapping(value = URIConstants.GET_IDS, method = RequestMethod.GET)
public ResponseEntity<List<UserMovieReviewData>> getReview(
#RequestParam(value = ReviewConstants.TYPE, required = true) String type, #PathVariable(value = "ids") String reviewIds)
{
getMovieReviewExecutor.setAttribute(ReviewConstants.TYPE, type);
getMovieReviewExecutor.setAttribute(ReviewConstants.REVIEW_IDS, reviewIds);
return performTask(null, getMovieReviewExecutor);
}
}
I am using spring 4 + hibernate 4.
I am getting the following error when I am trying to get data from Rest web service call:
I am getting the following error when I am trying to fetch the data from Rest web service:
org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:238)
org.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:208)
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:161)
org.springframework.web.servlet.mvc.method.annotation.HttpEntityMethodProcessor.handleReturnValue(HttpEntityMethodProcessor.java:144)
org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:71)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:128)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:781)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:721)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:186)
org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344)
org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261)
root cause
com.fasterxml.jackson.databind.JsonMappingException: could not initialize proxy - no Session (through reference chain: java.util.ArrayList[0]->com.ampdev.platform.module.movie.review.user.dataobject.UserMovieReviewData["movieData"]->com.ampdev.platform.module.movie.dataobject.MovieData_$$_jvst49f_5["id"])
com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:232)
com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:197)
com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:187)
com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:652)
com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:152)
com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:541)
com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:644)
com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:152)
com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:100)
com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:21)
com.fasterxml.jackson.databind.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:183)
com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:114)
com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:1837)
org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:231)
org.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:208)
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:161)
org.springframework.web.servlet.mvc.method.annotation.HttpEntityMethodProcessor.handleReturnValue(HttpEntityMethodProcessor.java:144)
org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:71)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:128)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:781)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:721)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:186)
org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344)
org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261)
root cause
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:165)
org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:286)
org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:185)
com.ampdev.platform.module.movie.dataobject.MovieData_$$_jvst49f_5.getId(MovieData_$$_jvst49f_5.java)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
com.fasterxml.jackson.databind.ser.BeanPropertyWriter.get(BeanPropertyWriter.java:726)
com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:506)
com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:644)
com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:152)
com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:541)
com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:644)
com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:152)
com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:100)
com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:21)
com.fasterxml.jackson.databind.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:183)
com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:114)
com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:1837)
org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:231)
org.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:208)
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:161)
org.springframework.web.servlet.mvc.method.annotation.HttpEntityMethodProcessor.handleReturnValue(HttpEntityMethodProcessor.java:144)
org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:71)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:128)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:781)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:721)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:186)
org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344)
org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261)
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
You're trying to access a lazy collection outside of the hibernate session. There are a few ways to solve this, the most clear is to access the size() of each collection you're going to be serializing in your service class, which causes the collection to be loaded and therefore available outside the session.
Another alternative is to annotate the collection with FetchType.EAGER, but this will affect all uses of your model, which might not be what you want. Finally, you can use the OpenSessionInView pattern, which maintains an open hibernate session for the duration of the request (and therefore allows you to load lazy collections outside where the session boundary would otherwise be). This last alternative is generally considered an anti-pattern.
I'm trying to retrieve data from database in Primefaces datatable. My database table name is dept and it has two columns id (int not null primary key) and name (varchar 255 not null). I'm using println to show size of records. But after starting project nothing show up. In database table are 2 records.
DeptTest.java
package logon;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import javax.annotation.PostConstruct;
import javax.enterprise.context.SessionScoped;
import javax.faces.bean.ViewScoped;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceUnit;
import javax.persistence.Query;
#ViewScoped
#SessionScoped
#javax.faces.bean.ManagedBean(name = "depTest")
public class DeptTest implements Serializable {
private static final long serialVersionUID = 1L;
private static final ArrayList<Department> orderList = new ArrayList<Department>();
public ArrayList<Department> getOrderList() {
return orderList;
}
#PersistenceUnit(unitName = "Webbeans_RESOURCE_LOCAL")
private EntityManagerFactory emf;
public List<Department> getDeptList() {
return deptList;
}
public void setDeptList(List<Department> deptList) {
this.deptList = deptList;
}
public List<Department> deptList = new ArrayList();
#PostConstruct
public void init() {
EntityManager em = emf.createEntityManager();
// Read the existing entries and write to console
Query q = em.createQuery("SELECT d FROM Dept d");
deptList = q.getResultList();
System.out.println("Size dept: " + deptList.size());
}
}