Spring Hibernate - NullPointerException SessionFactory

Question

I got an error about SessionFactory.

CrudController.java

@Controller
public class CrudController {

@Autowired
private AlbumBo albumBo;

@RequestMapping(value = "/addAlbum")
@ResponseBody
public void addAlbum(
        @RequestParam("NameRecordCompany") String nameRecordCompany,
        @RequestParam("NameAlbum") String nameAlbum,
        @RequestParam("YearName") String yearAlbum,
        @RequestParam("NameArtist") String nameArtist,
        @RequestParam("NameCategory") String nameCategory,
        @RequestParam("SongList") String songList) throws JSONException {

    Song temp = new Song();
    ArrayList<Song> listaCanzoni = new ArrayList();

    String songs = "{" + "\"songs\":" + songList + "}";
    JSONObject jsonObjectSongList = new JSONObject(songs);
    JSONArray jsonArraySongList = (JSONArray) jsonObjectSongList.get("songs");

    for (int i = 0; i < jsonArraySongList.length(); i++) {
        temp.setName((String) jsonArraySongList.getJSONObject(i).get("songName"));
        temp.setDuration((String) jsonArraySongList.getJSONObject(i).get("songDuration"));

        listaCanzoni.add(new Song(temp.getName(), temp.getDuration()));
    }

    Artist artist = new Artist(nameArtist);
    Category category = new Category(nameCategory);
    Album album = new Album(nameAlbum, yearAlbum);

    album.setArtist(artist);
    album.setCategory(category);

    try {
        albumBo.save(album); //line 67
        JOptionPane.showMessageDialog(null, "albumDao.save(album) eseguita");
    } catch(Exception ex) {
        ex.printStackTrace();
    } 

}

}

AlbumDaoImpl.java

public class AlbumDaoImpl implements AlbumDao {

@Autowired
SessionFactory sessionFactory;

public SessionFactory getSessionFactory() {
    return sessionFactory;
}

public void setSessionFactory(SessionFactory factory) {
    this.sessionFactory = factory;
}  

@Override
public void save(Album album) throws Exception {
    Session session = sessionFactory.openSession(); //line 38
    Transaction tx = null;

    try {
        tx = session.beginTransaction();
        session.saveOrUpdate(album);
        tx.commit();
    } catch (HibernateException e) {
        if (tx != null) {
            tx.rollback();
        } else {
            e.printStackTrace();
        }
    } finally {
        session.close();
    }
}
}

AlbumBoImpl.java

public class AlbumBoImpl implements AlbumBo{

private AlbumDao albumDao;

static final Logger logger = Logger.getLogger(AlbumBoImpl.class);

public AlbumDao getAlbumDao() {
    return albumDao;
}

public void setAlbumDao(AlbumDao albumDao) {
    this.albumDao = albumDao;
}

@Override
public void save(Album album) throws Exception {
    try{
        albumDao.save(album); //line 35
    }catch(Exception e){
        logger.error(e);
        throw e;
    } 
}
}

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:context="http://www.springframework.org/schema/context"
   xmlns:p="http://www.springframework.org/schema/p"
   xmlns:tx="http://www.springframework.org/schema/tx/spring-tx-4.0.xsd"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
   http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
   http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

<bean id="dataSource"
      class="org.springframework.jdbc.datasource.DriverManagerDataSource"
      p:driverClassName="${jdbc.driverClassName}"
      p:url="${jdbc.url}"
      p:username="${jdbc.username}"
      p:password="${jdbc.password}"/>

<bean id="propertyConfigurer"
      class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"
      p:location="/WEB-INF/jdbc.properties" />

<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="annotatedClasses">
        <list>
            <value>it.davidefruci.casadiscografica2.beans.Album</value>
            <value>it.davidefruci.casadiscografica2.beans.Artist</value>
            <value>it.davidefruci.casadiscografica2.beans.Song</value>
            <value>it.davidefruci.casadiscografica2.beans.RecordCompany</value>
            <value>it.davidefruci.casadiscografica2.beans.Category</value>
        </list>
    </property>
    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
            <prop key="hibernate.show_sql">true</prop>
            <prop key="hibernate.hbm2ddl.auto">update</prop>
        </props>
    </property>
</bean>

<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
    <property name="dataSource" ref="dataSource" />
    <property name="sessionFactory" ref="sessionFactory" />
</bean>

<!-- DAO -->
<bean id="albumDao" class="it.davidefruci.casadiscografica2.daoImpl.AlbumDaoImpl"/>    
<bean id="artistDao" class="it.davidefruci.casadiscografica2.daoImpl.ArtistDaoImpl"/>    
<bean id="categoryDao" class="it.davidefruci.casadiscografica2.daoImpl.CategoryDaoImpl"/>    
<bean id="recordCompanyDao" class="it.davidefruci.casadiscografica2.daoImpl.RecordCompanyDaoImpl"/>    
<bean id="songDao" class="it.davidefruci.casadiscografica2.daoImpl.SongDaoImpl"/>     

<!-- BO -->
<bean id="albumBo" class="it.davidefruci.casadiscografica2.boImpl.AlbumBoImpl">
    <property name="albumDao" ref="albumDao"></property>
</bean>
<bean id="artistBo" class="it.davidefruci.casadiscografica2.boImpl.ArtistBoImpl">
    <property name="artistDao" ref="artistDao"></property>
</bean>    
<bean id="categoryBo" class="it.davidefruci.casadiscografica2.boImpl.CategoryBoImpl">
    <property name="categoryDao" ref="categoryDao"></property>
</bean>    
<bean id="recordCompanyBo" class="it.davidefruci.casadiscografica2.boImpl.RecordCompanyBoImpl">
    <property name="recordCompanyDao" ref="recordCompanyDao"></property>
</bean>    
<bean id="songBo" class="it.davidefruci.casadiscografica2.boImpl.SongBoImpl">
    <property name="songDao" ref="songDao"></property>
</bean>

I have a JSP where I add the datas that I want to save into my db. When I click on the submit button, an Ajax call is invoked. This call invokes the CrudController, who should save data on my db with addAlbum method.

When the CrudController is invoked Tomcat tells me:

java.lang.NullPointerException at it.davidefruci.casadiscografica2.daoImpl.AlbumDaoImpl.save(AlbumDaoImpl.java:38) at it.davidefruci.casadiscografica2.boImpl.AlbumBoImpl.save(AlbumBoImpl.java:35) at it.davidefruci.casadiscografica2.controllers.CrudController.addAlbum(CrudController.java:67) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:777) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:706) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857) at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1521) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1478) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:745)

I wrong something with the sessionFactory initialization?

Answer 1

<bean id="personDao"class="com.studytrails.tutorials.springhibernatesessionfactory.PersonDao">
        <property name="sessionFactory" ref="sessionFactory" />
        </bean>

You will need to inject session factory in DAO you are using which will help you do CRUD operations on your Object either you can configure this in XML or using annotation.

Also please help your self by going through the given like below
Example of spring hibernate integration

Answer 2

Two things you can do, one is change to inject the SessionFactory to Dao by yourself.

<!-- DAO -->
<bean id="albumDao" class="it.davidefruci.casadiscografica2.daoImpl.AlbumDaoImpl">
    <property name="sessionFactory" ref="sessionFactory"/>
</bean>   

You can do this for all DAOs.

Or

put a component scan on the applicationContext.xml XML configuration so that the SessionFactory will get Autowired.

<context:component-scan base-package="it.davidefruci.casadiscografica2"/>