I'm really new to hibernate and try to understand how it works. But know I faced with the problem.
First of all, I have such mapping:
#Entity
public class Author {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
private String name;
public Author() {
}
public long getId() {
return id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
But then, when I tried to save this entitye with session.save(), hibernate showed me error like
Exception in thread "main" org.hibernate.exception.ConstraintViolationException: could not execute statement
Caused by: org.postgresql.util.PSQLException: ERROR: null value in column "id" of relation "author" violates not-null constraint
Failing row contains (null, hello!).
So I decided to notice, why hibernate doesn't increment the id automaticy and recognized that POSTGRESQL doesn't suppert annotation GenerationType.IDENTITY. So I changet it to the GenerationType.SEQUENCE. The error was gone, but entity wasn't saved.
So here's hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="connection.url">jdbc:postgresql://localhost:5432/hibernate?useSSL=false
&serverTimezone=UTC</property>
<property name="connection.driver_class">org.postgresql.Driver</property>
<property name="dialect">org.hibernate.dialect.PostgreSQL9Dialect</property>
<property name="connection.username">postgres</property>
<property name="connection.password">4122</property>
<property name="hibernate.current_session_context_class">thread</property>
<property name="hibernate.hbm2ddl.auto">update</property>
<mapping class="hibernate.entity.Author"/>
<!-- DB schema will be updated if needed -->
<!-- <property name="hibernate.hbm2ddl.auto">update</property> -->
</session-factory>
</hibernate-configuration>
Here's HibernateUtil.java
public class HibernateUtil {
private static SessionFactory sessionFactory;
private static SessionFactory buildSessionFactory() {
StandardServiceRegistry standardRegistry = new StandardServiceRegistryBuilder()
.configure("hibernate.cfg.xml").build();
Metadata metadata = new MetadataSources(standardRegistry).getMetadataBuilder()
.build();
SessionFactoryBuilder sessionFactoryBuilder = metadata.getSessionFactoryBuilder();
return sessionFactoryBuilder.build();
}
public static SessionFactory getSessionFactory() {
if(sessionFactory == null) {
sessionFactory = buildSessionFactory();
}
return sessionFactory;
}
}
And here's the Main.java, where I call the hibernate functions:
public class Main {
public static void main(String[] args) {
try(Session session = HibernateUtil.getSessionFactory().openSession()) {
Transaction tx = session.beginTransaction();
Author author = new Author();
author.setName("hello!");
session.save(author);
tx.commit();
System.out.println(session.get(Author.class, 1L));
}
}
}
After program execution it prints me null and there is no entity in database:
If you know, what can be the problem, please tell me. I'd really apreciate it!
I think the reason is setter for id missing:
public long setId(long id) {
this.id = id;
}
Related
This question already has answers here:
Hibernate 5 :- org.hibernate.MappingException: Unknown entity
(6 answers)
Closed 5 years ago.
I am creating a simple application using Hibernate JPA (annotations) and MySQL.I keep getting a:
WARN: HHH000183: no persistent classes found for query class: from
tn.ensi.cloudtrustproject.dao.entity.Country
when testing the Hibernate mapping.
I could not locate the problem so far. Please any help.
This is my hibernate.cfg.xml:
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property
name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name=
"hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name=
"hibernate.connection.url">jdbc:mysql://127.0.0.1:3306/TrustCloud</property>
<property name="hibernate.connection.pool_size">1</property>
<property name=
"hibernate.cache.provider_class">org.hibernate.cache.NoCacheProvider
</property>
<property name= "hibernate.show_sql">true</property>
<property name="hibernate.hbm2ddl.auto">update</property>
<property name="current_session_context_class">thread</property>
<mapping class="tn.ensi.cloudtrustproject.dao.entity.Country" ></mapping>
<mapping class="tn.ensi.cloudtrustproject.dao.entity.CloudUser"></mapping>
</session-factory>
</hibernate-configuration>
This is HibernateUtil:
public class HibernateUtil {
private static SessionFactory sessionFactory= buildSessionFactory();
private static ServiceRegistry serviceRegistry;
private static Session session=null;
private static SessionFactory buildSessionFactory(){
try{
Configuration configuration= new Configuration();
configuration.configure("config/hibernate.cfg.xml");
serviceRegistry=new
StandardServiceRegistryBuilder().
applySettings(configuration.getProperties()).build();
return configuration.buildSessionFactory (serviceRegistry);
}
catch (Throwable ex){
System.err.println("Failed to cerate SessionFactory object"+ ex);
throw new ExceptionInInitializerError(ex);
}
}
public static SessionFactory getSessionFactory(){
return sessionFactory;
}
public static Session openSession(){
return sessionFactory.openSession();
}
public static Session getCurrentSession(){
return sessionFactory.getCurrentSession();
}
public static void close(){
sessionFactory.close();
}
}
The class Test.java:
package tn.ensi.cloudtrustproject.util;
import java.util.List;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
public class Test {
static Session session= HibernateUtil.openSession();
public static void main(String[] args) {
session.createQuery("from tn.ensi.cloudtrustproject.dao.entity.Country
").list();
}
}
The entity class:
package tn.ensi.cloudtrustproject.dao.entity;
import java.io.Serializable;
import javax.persistence.*;
#Entity
#Table(name="country")
public class Country implements Serializable{
private static final long serialVersionUID = 1L;
#Id #GeneratedValue
#Column(name="countryid")
private Integer countryId ;
#Column(name="countrydes")
private String countryDes;
public Country(Integer countryId, String countryDes) {
super();
this.countryId = countryId;
this.countryDes = countryDes;
}
public Country() {
super();
// TODO Auto-generated constructor stub
}
public Integer getCountryId() {
return countryId;
}
public void setCountryId(Integer countryId) {
this.countryId = countryId;
}
public String getCountryDes() {
return countryDes;
}
public void setCountryDes(String countryDes) {
this.countryDes = countryDes;
}
public static long getSerialversionuid() {
return serialVersionUID;
}
#Override
public String toString() {
return "Country [countryId=" + countryId + ", countryDes=" + countryDes
+ "]";
}
}
The project:
project
The table is created:
Table country
you have mentioned configuration file exists in config/hibernate.cfg.xml. Please check whether it is existing in same location.
I have very strange problem and I can't understand it's reason.
I tried to save simple Object (Group.class) with only 1 field (#id groupName), getter and setter.
When I try to run my program, I have an exception:
Exception in thread "main" org.hibernate.exception.SQLGrammarException: Could not execute JDBC
batch update at
...
Caused by: java.sql.BatchUpdateException: You have an error in your
SQL syntax; check the manual that corresponds to your MySQL server
version for the right syntax to use near 'Group (groupName) values
('Test')' at line 1
But if I specify the name of entity (different of Group) all works fine.
Could you please explain me what I've done wrong?
Code:
hibernate.cfg.xml
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.bytecode.use_reflection_optimizer">false</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/test</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name="dialect">org.hibernate.dialect.MySQL5Dialect</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto">create</property>
<mapping class="com.globallogic.dto.Group"></mapping>
</session-factory>
</hibernate-configuration>
import javax.persistence.*;
Group.class
#Entity //this doesn't work
//#Entity(name = "SomeName") // this works good
public class Group {
#Id
private String groupName;
public void setGroupName(String groupName) {
this.groupName = groupName;
}
public String getGroupName() {
return groupName;
}
}
DataSender.class
public class DataSender {
private SessionFactory sessionFactory;
public DataSender() {
sessionFactory = new Configuration().configure()
.buildSessionFactory();
}
public void sendData(Object... objects) {
Session session = sessionFactory.openSession();
if (session.isConnected()) {
System.out.println("ALL IS GOOD");
session.beginTransaction();
for (Object user: objects) {
session.persist(user);
}
System.out.println();
session.getTransaction().commit();
session.close();
System.out.println("Connection is closed");
}
sessionFactory.close();
}
}
Main.class
public class Main {
public static void main(String[] args) {
DataSender ds = new DataSender();
Group group = new Group();
group.setGroupName("Test");
ds.sendData(group);
}
}
Group is an SQL keyword, you'll need to quote your table name:
#Entity
#Table(name = "`Group`")
public class Group {
....
I have a question about my hibernate mapping, I am creating a project with Spring and hibernate, I am facing a issue that I can solve it so far and I couldn't find someone able to help me so far, so I mapped the database and did everything as expected but I am receiving this message:
HHH000183: no persistent classes found for query class: FROM com.inbox.model.Estado
My hibernate.cfg.xml is like this
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">com.mysql.cj.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://inboxmysqldb.c4lcntgo83fr.us-west-2.rds.amazonaws.com</property>
<property name="hibernate.connection.username">inboxuser</property>
<property name="hibernate.connection.password">xxxxxx</property>
<!-- <property name="hibernate.dialect">org.hibernate.dialect.HSQLDialect</property> -->
<property name="hibernate.show_sql">false</property>
<!-- <property name="hibernate.hbm2ddl.auto">true</property>-->
<property name="hibernate.connection.pool_size">10</property>
<property name="hibernate.current_session_context_class">thread</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Mapping files -->
<!-- <mapping class="com.inbox.model.Box"/> -->
<mapping class="com.inbox.model.Estado"/>
</session-factory>
</hibernate-configuration>
My class is mapped like this:
package com.inbox.model;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.UniqueConstraint;
#Entity(name="com.inbox.model.Estado")
#Table(name = "estado",
uniqueConstraints={#UniqueConstraint(columnNames={"id"})})
public class Estado implements IdentifierInterface, Serializable{
/**
*
*/
private static final long serialVersionUID = 3625863483844458267L;
#Id
#GeneratedValue(strategy = javax.persistence.GenerationType.IDENTITY)
#Column(name="id", nullable=false, unique=true, length=11)
private Integer id;
#Column(name="nome", length=20, nullable=true)
private String nome;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getNome() {
return nome;
}
public void setNome(String nome) {
this.nome = nome;
}
}
HibernateUtil:
public class HibernateUtil {
private static SessionFactory sessionFactory = buildSessionFactory();
private static SessionFactory buildSessionFactory() {
if (sessionFactory == null) {
Configuration configuration = new Configuration();
configuration.configure("hibernate.cfg.xml");
ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
.applySettings(configuration.getProperties()).build();
sessionFactory = configuration.buildSessionFactory(serviceRegistry);
}
return sessionFactory;
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
public static Session getSession() {
return getSessionFactory().openSession();
}
}
As requested follow the query
public T findById(int id) {
Session session = HibernateUtil.getSession();
session.beginTransaction();
try {
Query byIdQuery = session.createQuery("FROM " + entityClassName + " as c WHERE c.id = :id");
byIdQuery.setParameter("id", id);
return (T) byIdQuery.uniqueResult();
} catch (Exception e) {
throw new InboxException(e);
} finally {
session.close();
}
}
I ran out of ideas to try fix.
Thanks in advance
This question is different from the other questions on the same topic of MappingException: Unknown entity because I have this line in my hibernate config:
<mapping class="bbb.Students" />
My entity class is as follows:
package bbb;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
#Entity
#Table(name = "Students")
public class Students implements java.io.Serializable {
private String id;
private String name;
private String number;
#Id
#Column(name = "ID", unique = true, nullable = false)
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
#Column(name = "NAME", nullable = false)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
#Column(name = "NUMBER", nullable = false)
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
}
I have the database test and the table Students manually created.
The error is:
org.hibernate.MappingException: Unknown entity: bbb.Students
Exception in thread "main" org.hibernate.MappingException: Unknown entity: bbb.Students
at org.hibernate.internal.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:776)
at org.hibernate.internal.SessionImpl.getEntityPersister(SessionImpl.java:1533)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:104)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:192)
at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:38)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:177)
at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:32)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73)
at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:682)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:674)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:669)
at bbb.App.main(App.java:39)
The Main class is as follows:
package bbb;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
public class App
{
public static void main( String[] args )
{
System.out.println("Hibernate one to one (Annotation)");
Configuration conf = new Configuration();
SessionFactory sf = conf.configure()
.buildSessionFactory(
new StandardServiceRegistryBuilder()
.applySettings(conf.getProperties())
.build());
Session session = sf.openSession();
session.beginTransaction();
Students s = new Students();
s.setId("1");
s.setName("Joe");
s.setNumber("12345");
session.save(s);
session.getTransaction().commit();
System.out.println("Done");
}
}
The full hibernate.config is as follows:
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/test</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="show_sql">true</property>
<mapping class="bbb.Students" />
</session-factory>
</hibernate-configuration>
Just imported your Students class in a Hibernate based project. Everything work fine. Before running the application, I created schema "test" manually. Post a class with the main method. Probably something is wrong in it.
Update:
Imported your's main method. The application still works. Can't reproduce an issue.
import bbb.Students;
import org.hibernate.*;
import org.hibernate.cfg.Configuration;
public class Main {
private static final SessionFactory ourSessionFactory;
static {
try {
ourSessionFactory = new Configuration().
configure("hibernate.cfg.xml").
buildSessionFactory();
} catch (Throwable ex) {
throw new ExceptionInInitializerError(ex);
}
}
public static Session getSession() throws HibernateException {
return ourSessionFactory.openSession();
}
public static void main(final String[] args) throws Exception {
final Session session = getSession();
try {
Transaction transaction= session.beginTransaction();
Students student = new Students();
student.setName("Vasua");
student.setNumber("13");
student.setId("1");
session.save(student);
transaction.commit();
} finally {
session.close();
}
}
}
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernte Configuration DTD//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="connection.url">
jdbc:mysql://localhost/stack
</property>
<property name="connection.driver_class">
com.mysql.jdbc.Driver
</property>
<property name="connection.username">
root
</property>
<property name="connection.password">
root
</property>
<!-- DB schema will be updated if needed -->
<property name="hbm2ddl.auto">update</property>
<mapping class="bbb.Students"/>
</session-factory>
</hibernate-configuration>
It's my first time configuring hibernate. I've read many tutorials but not sure why this is creating the wrong create table sql statement. I am using PostgreSQL as my database.
hibernate.cfg.xml
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.dialect">org.hibernate.dialect.PostgreSQL9Dialect</property>
<property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
<property name="hibernate.connection.url">jdbc:postgresql://DBIP:5432/MYDB</property>
<property name="hibernate.connection.username">MYDB</property>
<property name="hibernate.connection.password">MYPASS</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto">create</property>
<property name="show_sql">true</property>
<mapping class="MYPROJ.model.User"/>
</session-factory>
</hibernate-configuration>
User.java
package MYPROJ.model;
import javax.persistence.*;
#Entity
public class User
{
#Id #GeneratedValue
#Column(name = "id")
private int id;
#Column(name = "username")
private String username;
#Column(name = "age")
private int age;
public int getId()
{
return id;
}
public void setId(int id)
{
this.id = id;
}
public String getUsername()
{
return username;
}
public void setUsername(String username)
{
this.username = username;
}
public int getAge()
{
return age;
}
public void setAge(int age)
{
this.age = age;
}
}
Main.java
public class Main
{
public static void main(String[] args)
{
User user = new User();
user.setId(1);
user.setAge(20);
user.setUsername("david");
SessionFactory sessionFactory;
ServiceRegistry serviceRegistry;
Configuration configuration = new Configuration();
configuration.configure();
serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
sessionFactory = configuration.buildSessionFactory(serviceRegistry);
Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(user);
session.getTransaction().commit();
System.out.println("Done!");
}
}
When I run the program it shows the following SQL statement for creating the table which does not work when I run the program or when I copy pasted it manually
create table User (id int4 not null, age int4, username varchar(255), primary key (id))
What am I doing wrong here?
It turned out that "user" was a reserved keyword in PostgreSQL, changing that fixed the issue.
You can tell hibernate your column name must be escaped to avoid conflicts with the database keywords. To do that, enclose the name between `. Example:
#Column(name="`user`")