I'm getting this exceptions:
javax.el.ELException: Error reading 'id' on type com.example.model.Article_$$_javassist_2
...
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:149)
org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:195)
org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:185)
com.example.model.Article_$$_javassist_2.getId(Article_$$_javassist_2.java)
...
Here's my code:
@Entity
@Table( name = "tbl_articles" )
public class Article implements Comparable<Article>, Serializable
{
private static final long serialVersionUID = 1L;
@Id
@Column( nullable = false )
@GeneratedValue( strategy = GenerationType.IDENTITY )
private Integer id;
// some other fields
@ManyToMany( cascade = { CascadeType.ALL } )
@JoinTable( name = "tbl_articles_categories",
joinColumns = { @JoinColumn( name = "article_id" ) },
inverseJoinColumns = { @JoinColumn( name = "category_id" ) })
@ForeignKey( name = "tbl_articles_categories_fkey_article",
inverseName = "tbl_articles_categories_fkey_category" )
private Set<Category> categories = new HashSet<Category>();
@ManyToMany( cascade = { CascadeType.ALL } )
@JoinTable( name = "tbl_articles_tags",
joinColumns = { @JoinColumn( name = "article_id" ) },
inverseJoinColumns = { @JoinColumn( name = "tag_id" ) })
@ForeignKey( name = "tbl_articles_tags_fkey_article",
inverseName = "tbl_articles_tags_fkey_tag" )
private Set<Tag> tags = new HashSet<Tag>();
// getters and setters
}
public abstract class BaseService<E, D extends BaseDAO<E>>
{
protected D dao;
public BaseService()
{
}
protected D getDao()
{
return dao;
}
@Autowired
protected void setDAO( D dao )
{
this.dao = dao;
}
@Transactional
public E get( int id )
{
return dao.get( id );
}
}
@Service
public class ArticleService extends BaseService<Article, ArticleDAO>
{
public ArticleService()
{
setDAO( dao );
}
}
public abstract class BaseDAO<E>
{
public abstract E get( int id );
}
@Repository
public class ArticleDAO extends BaseDAO<Article>
{
@Autowired
private SessionFactory sessionFactory;
@Override
public Article get( int id )
{
return ( Article ) sessionFactory.getCurrentSession().load( Article.class, id );
}
}
In my Controller now, I'm using this to get a specific article:
@RequestMapping( "/{id}/{title}.html" )
public String article( @PathVariable( "id" ) Integer id, Map<String, Object> map )
{
map.put( "article", articleService.get( id ) );
return "article";
}
Which I'm using in my JSP just like this:
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<%@ taglib prefix="slg" uri="http://github.com/slugify" %>
<article>
<c:url value="/blog/${article.id}/${slg:slugify(article.title)}.html" var="articleUrl" />
<h2><a href="${articleUrl}">${article.title}</a></h2>
<span><fmt:formatDate value="${article.creationDate}" pattern="E, dd MMM yyyy" /></span>
<p>
${article.text}
</p>
</article>
Here's my hibernate configuration as well:
# Properties file with Hibernate Settings.
#-------------------------------------------------------------------------------
# Common Settings
hibernate.generate_statistics=false
#hibernate.hbm2ddl.auto=update
hibernate.show_sql=false
#-------------------------------------------------------------------------------
# DB specific Settings
# Property that determines which Hibernate dialect to use
hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect
What I'm doing wrong?
UPDATE
Debugging sessionFactory.getCurrentSession() results in:
DEBUG : com.example.model.ArticleDAO - SessionImpl(PersistenceContext[entityKeys=[],collectionKeys=[]];ActionQueue[insertions=[] updates=[] deletions=[] collectionCreations=[] collectionRemovals=[] collectionUpdates=[] unresolvedInsertDependencies=UnresolvedEntityInsertActions[]])
I'm adding some global variables, maybe this causing the errors? In my controller there's a method:
@ModelAttribute
public void addGlobalObjects( Map<String, Object> map )
{
map.put( "section", "blog" );
SortedMap<Category, Integer> categories = new TreeMap<Category, Integer>();
for ( Category category : categoryService.list() )
{
categories.put( category, articleService.size( category ) );
}
Calendar cal = Calendar.getInstance();
cal.set( Calendar.DAY_OF_MONTH, 1 );
cal.add( Calendar.MONTH, ARCHIVE_MONTHS * -1 );
SortedMap<Date, Integer> archive = new TreeMap<Date, Integer>();
for ( int i = 0; i < ARCHIVE_MONTHS; ++i )
{
cal.add( Calendar.MONTH, 1 );
archive.put( cal.getTime(), articleService.size( cal ) );
}
SortedMap<Tag, Integer> tags = new TreeMap<Tag, Integer>();
for ( Tag tag : tagService.list() )
{
tags.put( tag, articleService.size( tag ) );
}
map.put( "categories", categories );
map.put( "archive", archive );
map.put( "tags", tags );
map.put( "categoriesSize", categoryService.size() );
map.put( "tagsSize", tagService.size() );
map.put( "date", new Date() );
}
For updated article entity see above.
UPDATE2
Eager fetching didn't solved the problem - still the same exception:
@ManyToMany( fetch = FetchType.EAGER, cascade = { CascadeType.ALL } )
And finally I'm getting duplicated articles what I don't need...
UPDATE3
Trying Hibernate.initialize() I'm getting this exception:
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.LazyInitializationException: could not initialize proxy - no Session
UPDATE4
I changed my get method this way:
@Override
public Article get( int id )
{
// return ( Article ) sessionFactory.getCurrentSession().load( Article.class, id );
return ( Article ) sessionFactory.getCurrentSession().createCriteria( Article.class ).add( Restrictions.eq( "id", id ) ).uniqueResult();
}
This is NOT a solution, but as I can't handle this problem I'll use this temporarily.
I already tried this (as mentioned here) without success (it changed the ELException from Error reading 'id' on type ... to Error reading 'title' on type ... - maybe i used it wrong?):
@Override
public Article get( int id )
{
Article ret = ( Article ) sessionFactory.getCurrentSession().load( Article.class, id );
sessionFactory.getCurrentSession().update( ret );
return ret;
}
A solution is still needed!
