A tentative study of Hibernate course single-table mapping 2-6 Session details (bottom)

The main contents of this section:

1 introduces the difference between Getcurrentsession and opensession.

2 Demo: Compare two sessions by printing to verify that two sessions are the same session

3 Demo: Verify that the session is not closed by printing hashcode, easy to connect pool overflow.

1 The difference between getcurrentsession and opensession

A getcurrentsession each fetch is the same connection, opensession each gets a different connection.

b getcurrentsession does not need to be closed manually, and shuts down automatically after committing a transaction. Opensession need to be closed manually, if not closed, the number of connections exhausted, easy connection pool overflow.

2 Demo1

Package hibernate_001;

Import Java.sql.Array; Import Java.sql.Blob; Import java.sql.CallableStatement; Import Java.sql.Clob; Import Java.sql.DatabaseMetaData; Import Java.sql.NClob; Import java.sql.PreparedStatement; Import java.sql.SQLClientInfoException; Import java.sql.SQLException; Import java.sql.SQLWarning; Import Java.sql.SQLXML; Import Java.sql.Savepoint; Import java.sql.Statement; Import java.sql.Struct; Import Java.util.Date; Import Java.util.Map; Import java.util.Properties; Import Java.util.TimeZone; Import Java.util.concurrent.Executor;

Import org.hibernate.Session; Import Org.hibernate.SessionFactory; Import org.hibernate.Transaction; Import org.hibernate.cfg.Configuration; Import Org.hibernate.jdbc.Work; Import Org.hibernate.service.ServiceRegistry; Import Org.hibernate.service.ServiceRegistryBuilder; Import Org.junit.After; Import Org.junit.Before; Import Org.junit.Test;

Import com.ddwei.student.Student; import com.mysql.jdbc.Connection; import com.mysql.jdbc.ExceptionInterceptor; Import com.mysql.jdbc.Extension; Import com.mysql.jdbc.MySQLConnection; Import Com.mysql.jdbc.log.Log;

public class Studenttest {   private sessionfactory sessionfactory;  private session session;  priva Te Transaction trasaction;     @Test  public void Testsavestudent () {  //Get the Configuration object and get the contents of the Hibernate.cfg.xml configuration    Configuration config = new configuration (). Configure ();   //Gets the service registration object, gets the contents of the Hibernate.hbm.xml configuration   serviceregistry sry = new Serviceregistrybuilder (). Applysettings (Config.getproperties ()). Buildserviceregistry ();      sessionfactory sfy = config.buildsessionfactory (SRY);   session Sesion1 = Sfy.opensession ();   session Sesion2 = Sfy.opensession ();      system.out.println (Sesion1==sesion2);      //  student Student =new Student (3, "Zhou Enlai", "male", New Date (), "Shaoxing");//Create Student Object//   session.save (student);//Session Save student object into database  }         @Test  public void TestSaveStudent2 () {  //Get the Configuration object, get HibernatE.cfg.xml configuration content   configuration config = new configuration (). Configure ();   //Gets the service registration object, gets the contents of the Hibernate.hbm.xml configuration   serviceregistry sry = new Serviceregistrybuilder (). Applysettings (Config.getproperties ()). Buildserviceregistry ();      sessionfactory sfy = config.buildsessionfactory (SRY);   session Sesion1 = Sfy.getcurrentsession ();   session Sesion2 = Sfy.getcurrentsession ();      system.out.println (Sesion1==sesion2);      //  student Student =new Student (3, "Zhou Enlai", "male", New Date (), "Shaoxing");//Create Student Object//   session.save (student);//Session Save Student Object enter database  }  

}

Demo2

Package hibernate_001;

Import Java.sql.Array; Import Java.sql.Blob; Import java.sql.CallableStatement; Import Java.sql.Clob; Import Java.sql.DatabaseMetaData; Import Java.sql.NClob; Import java.sql.PreparedStatement; Import java.sql.SQLClientInfoException; Import java.sql.SQLException; Import java.sql.SQLWarning; Import Java.sql.SQLXML; Import Java.sql.Savepoint; Import java.sql.Statement; Import java.sql.Struct; Import Java.util.Date; Import Java.util.Map; Import java.util.Properties; Import Java.util.TimeZone; Import Java.util.concurrent.Executor;

Import org.hibernate.Session; Import Org.hibernate.SessionFactory; Import org.hibernate.Transaction; Import org.hibernate.cfg.Configuration; Import Org.hibernate.jdbc.Work; Import Org.hibernate.service.ServiceRegistry; Import Org.hibernate.service.ServiceRegistryBuilder; Import Org.junit.After; Import Org.junit.Before; Import Org.junit.Test;

Import com.ddwei.student.Student; Import com.mysql.jdbc.Connection; Import Com.mysql.jdbc.ExceptionInterceptor; Import com.mysql.jdbc.Extension; Import com.mysql.jdbc.MySQLConnection; Import Com.mysql.jdbc.log.Log;

public class StudentTest2 {   private sessionfactory sessionfactory;  private session session;  priv Ate Transaction trasaction;     @Test  public void Testsavestudent () {  //Get the Configuration object and get the contents of the Hibernate.cfg.xml configuration    Configuration config = new configuration (). Configure ();   //Gets the service registration object, gets the contents of the Hibernate.hbm.xml configuration   serviceregistry sry = new Serviceregistrybuilder (). Applysettings (Config.getproperties ()). Buildserviceregistry ();      sessionfactory sfy = config.buildsessionfactory (SRY);      session sesion1 = Sfy.opensession ();      sesion1.dowork (new work () {        @Override     public void Execute (java.sql.Connection Connection) throws SQLException {    //TODO auto-generated method Stub     system.out.println ("Connection.hashcode is" +connection.hashCode ());    }   });      student Student =new Student (4, "Zhou Enlai", "male", New Date (), "Shaoxing");//Create Student Object   sesion1.save (student);//Session Save Student Object Enter database

  session sesion2 = sfy.opensession ()   student student2 =new Student (5, "Zhou Enlai", "male", New Date (), " Shaoxing ");//Create Student Object   sesion2.dowork (new work () {        @Override     public void Execute (java.sql.Connection Connection) throws SQLException {    //TODO auto-generated method Stub     system.out.println ("Connection.hashcode is" +connection.hashCode ());    }   });      sesion2.save (STUDENT2);//Session Save Student Object Enter database

 }         @Test  public void TestSaveStudent2 () {  //Gets the configuration object, Get the contents of the hibernate.cfg.xml configuration   configuration config = new configuration (). Configure ();   //Gets the service registration object, gets the contents of the Hibernate.hbm.xml configuration   serviceregistry sry = new Serviceregistrybuilder (). Applysettings (Config.getproperties ()). Buildserviceregistry ();      sessionfactory sfy = config.buildsessionfactory (SRY);   session Sesion1 = Sfy.getcurrentsession ();   transaction tran = Sesion1.begintransaction ();   student Student =new Student (1, "Zhou Enlai", "male", New Date (), "Shaoxing");//Create Student Object   sesion1.dowork (new work () {    @Override    public void execute (java.sql.Connection Connection) throws SQLException {    //TODO auto-generated method Stub     system.out.println ( "Connection.hashcode is" +connection.hashcode ());    }   });   sesIon1.save (student);//Session Save Student Object Enter database   tran.commit ();         session sesion2 = Sfy.getcurrentsession ();   transaction tran2 = Sesion2.begintransaction ();

Student student2 =new Student (2, "Zhou Enlai", "male", New Date (), "Shaoxing");//Create Student Object Sesion2.dowork (new work () {@Override Publ IC void Execute (java.sql.Connection Connection) throws SQLException {//TODO auto-generated method stub System.ou    T.println ("Connection.hashcode is" +connection.hashcode ());   }   });     Sesion2.save (Student2);//Session Save Student Object Enter database Tran2.commit (); }

}

A tentative study of Hibernate course single-table mapping 2-6 Session details (bottom)