一 opensession与getCurrentSession的区别
1、 getCurrentSession在事务提交或者回滚之后会自动关闭，而openSession需要手动关闭。如果使用openSession而没有手动关闭，多次之后会导致连接池溢出。
2、openSession每次创建新的session对象，getCurrentSession使用现有的session对象。
二 测试openSession每次创建新的session对象
1、测试代码
@Test
public void testOpenSession(){
// 创建配置对象
Configuration config = new Configuration().configure();
// 创建服务注册对象
ServiceRegistry serviceRegistery = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry();
// 创建会话工厂对象
SessionFactory sessionFactory = config.buildSessionFactory(serviceRegistery);
// 创建会话对象
Session session1 = sessionFactory.openSession();
Session session2 = sessionFactory.openSession();
System.out.println(session1==session2);
}
2、运行结果
false
三 测试getCurrentSession使用现有的session对象
1、测试代码
@Test
public void testGetCurrentSession(){
// 创建配置对象
Configuration config = new Configuration().configure();
// 创建服务注册对象
ServiceRegistry serviceRegistery = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry();
// 创建会话工厂对象
SessionFactory sessionFactory = config.buildSessionFactory(serviceRegistery);
// 创建会话对象
Session session1 = sessionFactory.getCurrentSession();
Session session2 = sessionFactory.getCurrentSession();
System.out.println(session1==session2);
}
2、运行结果
true
四 openSession用完后必须手动关闭，否则会溢出
1、测试代码
@Test
public void testSaveStudentswithOpenSession(){
// 创建配置对象
Configuration config = new Configuration().configure();
// 创建服务注册对象
ServiceRegistry serviceRegistery = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry();
// 创建会话工厂对象
SessionFactory sessionFactory = config.buildSessionFactory(serviceRegistery);
// 创建会话对象
Session session1 = sessionFactory.openSession();
// 开启事务
Transaction transaction = session1.beginTransaction();
Students s= new Students(1,"张三丰","男",new Date(),"武当山");
session1.doWork(new Work(){
@Override
public void execute(Connection connection) throws SQLException {
// TODO Auto-generated method stub
System.out.println("connection hashCode:"+connection.hashCode());
}
});
session1.save(s);
//session.close();
transaction.commit();
Session session2 = sessionFactory.openSession();
transaction = session2.beginTransaction();
s= new Students(2,"李四","男",new Date(),"武当山");
session2.doWork(new Work(){
@Override
public void execute(Connection connection) throws SQLException {
// TODO Auto-generated method stub
System.out.println("connection hashCode:"+connection.hashCode());
}
});
session2.save(s);
transaction.commit();
}
2、测试结果
connection hashCode:1048278180
Hibernate:
insert
into
STUDENTS
(SNAME, GENDER, BIRTHDAY, ADDRESS, SID)
values
(?, ?, ?, ?, ?)
connection hashCode:156943829
Hibernate:
insert
into
STUDENTS
(SNAME, GENDER, BIRTHDAY, ADDRESS, SID)
values
(?, ?, ?, ?, ?)
五 getCurrentSession不用关闭session
1、测试代码
@Test
public void testSaveStudentswithGetCurrentSession(){
// 创建配置对象
Configuration config = new Configuration().configure();
// 创建服务注册对象
ServiceRegistry serviceRegistery = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry();
// 创建会话工厂对象
SessionFactory sessionFactory = config.buildSessionFactory(serviceRegistery);
// 创建会话对象
Session session1 = sessionFactory.getCurrentSession();
// 开启事务
Transaction transaction = session1.beginTransaction();
Students s= new Students(1,"张三丰","男",new Date(),"武当山");
session1.doWork(new Work(){
@Override
public void execute(Connection connection) throws SQLException {
// TODO Auto-generated method stub
System.out.println("connection hashCode:"+connection.hashCode());
}
});
session1.save(s);
transaction.commit();
Session session2 = sessionFactory.getCurrentSession();
transaction = session2.beginTransaction();
s= new Students(2,"李四","男",new Date(),"武当山");
session2.doWork(new Work(){
@Override
public void execute(Connection connection) throws SQLException {
// TODO Auto-generated method stub
System.out.println("connection hashCode:"+connection.hashCode());
}
});
session2.save(s);
transaction.commit();
}
2、运行结果
connection hashCode:455886737
Hibernate:
insert
into
STUDENTS
(SNAME, GENDER, BIRTHDAY, ADDRESS, SID)
values
(?, ?, ?, ?, ?)
connection hashCode:455886737
Hibernate:
insert
into
STUDENTS
(SNAME, GENDER, BIRTHDAY, ADDRESS, SID)
values
(?, ?, ?, ?, ?)