Hi All,
I met a weird problem with updating & displaying data in hibernate. Can anyone help me please!?
I am using hibernate, spring with mysql.
The problem here i am facing is, any changes can be applied to database. But if I load updated item on web page, it always returns the old data or new data randomly.
I am sure that it is not a problem of browser cache. I tried to print out return data in getPost method in dao class. It just print out wrong message sometimes.
Say, if I change post content for mutiple times, all changes can be stored in database. But If I continously refresh page to display changed data, it displays all previous changes randomly.
I have tried different ways to load data in getPost method, but still face same problem:
1. tried session.clear, and session.flush
2. close second level cache as :
<prop key="hibernate.cache.use_second_level_cache">false</prop>
<prop key="hibernate.cache.use_query_cache">false</prop>
<prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</prop>
<prop key="hibernate.cache.use_structured_entries">false</prop>
3. different way to load data: session.load, session.get, hibernate query, Criteria, all have same issue.
4. In getPost method of postDAO: I tried to load data by native sql first, and wanted to compare with result of hibernate query. both quries return old data.
Code:
Code:
public class Post implements Cloneable, Serializable {
private String postID;
private String content;
}
PostSelectController (controller):
public class PostSelectController extends AbstractController
{
....
protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception
{
String id = request.getParameter("id");
Course course = null;
Vendor vendor = null;
Post post = null;
ModelAndView modelAndView = new ModelAndView();
modelAndView.setViewName(getSuccessView());
post = postService.getPost(id);
modelAndView.addObject("post", post);
return modelAndView;
}
}
postService:
@Transactional(propagation=Propagation.SUPPORTS, isolation=Isolation.READ_COMMITTED, readOnly=true)
public class PostService
{
@Transactional(propagation=Propagation.REQUIRED, readOnly=false)
public boolean updatePost(Post post) {
System.out.println("service side::::::::::::::::::::::"+(post.getBestAnswer()!=null));
if(post.getBestAnswer()!=null) System.out.println(">>>>>>>>"+post.getBestAnswer().getPostID());
System.out.println("service side::::::::::::::::::::::"+(post.getBestAnswer()!=null));;
return this.postDAO.updatePost(post);
}
public Post getPost(String postID) {
return this.postDAO.getPost(postID);
}
}
postDAO:
public class PostDAO {
private SessionFactory sessionFactory;
...
public boolean updatePost(Post post) {
boolean proceed = true;
try {
Session session = sessionFactory.getCurrentSession();
session.merge(post); //tried session.update, same problem
session.flush(); //it does not help
} catch (Exception ex) {
logger.error(post.getPostID() + " refused :: " + ex.getMessage());
proceed = false;
}
return proceed;
}
public Post getPost(String postID) {
Session session = sessionFactory.getCurrentSession();
try{
PreparedStatement st = session.connection()
.prepareStatement("select content from post where postid='"+postID+"'") ;
ResultSet rs =st.executeQuery();
while (rs.next()) {
System.out.println("database::::::::::::::::::"+rs.getInt("content"));
// tried to use native sql to load data from database and compare it with result of hibernate query.
break;
}
}catch(Exception ex){
}
Criteria crit = session.createCriteria(Post.class);
NaturalIdentifier natId = Restrictions.naturalId();
natId.set("postID", postID);
crit.add(natId);
crit.setCacheable(false);
List<Post> posts = crit.list();
Post post = null;
if(posts!=null) post = posts.get(0);
System.out.println("hibernate::::::::::::::::::"+post.getContent());
return post;
}
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