Hibernate_在应用程序中使用的Session的管理方案

深藏阁楼爱情的钟 2022-06-16 10:54 185阅读 0赞

![Center][]

class txFilter implements Filter{
    	public void doFilter(request,response,chain){
    		session = sf.opensession();
    		Utils.threadLocal.set(session);// 绑定到当前线程上
    		try{
    			tx = session.beginTransaction();
    			chain.doFilter();// 放行
    			tx.commit();
    		}catch(Exception e){
    			tx.rollback();
    			throw e;
    		}finally{
    			session.close();
    			Utils.threadLocal.remove();// 移除
    		}	
    	}
    }	
    
    class UserDao{
    	public void saveUser(User user){
    		session = Utils.threadLocal.get();
    		session.save(User);
    	}
    }
    
    class txFilter增强 implements Filter{
    	public void doFilter(request,response,chain){
    		session = sf.getCurrentsession();
    		try{
    			tx = session.beginTransaction();
    			chain.doFilter();// 放行
    			tx.commit();
    		}catch(Exception e){
    			tx.rollback();
    			throw e;
    		}
    	}
    }
    
    class UserDao增强{
    	public void saveUser(User user){
    		session = sessionFactory.getCurrentsession();
    		session.save(User);
    	}
    }

/\*

package cn.itcast.m_session_manage;
    
    import org.hibernate.Session;
    
    public class Utils {
    	public static ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
    }

\*/

<!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 name="foo">
    		
    		
    		<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    		
    		<property name="connection.url">jdbc:mysql://localhost:3306/hibernate_20170423</property>
    		
    		<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
    		
    		<property name="connection.username">root</property>
    		
    		<property name="hibernate.connection.password">root</property>
    
    		
    		
    		<property name="hibernate.show_sql">true</property>
    		
    		<property name="hibernate.format_sql">false</property>
    
    		
    		<property name="hbm2ddl.auto">update</property>
    
    		
    		<property name="current_session_context_class">thread</property>
    
    		
    		
    
    	</session-factory>
    </hibernate-configuration>

package cn.itcast.m_session_manage;
    
    import org.hibernate.Session;
    import org.hibernate.SessionFactory;
    import org.hibernate.cfg.Configuration;
    import org.junit.Test;
    
    /**
     * 应用程序操作类
     * 
     * @author 风清杨
     * @version V3.0
     * 
     */
    public class App {
    	private static SessionFactory sessionFactory = new Configuration()//
    			.configure("cn/itcast/m_session_manage/myhibernate.cfg.xml")//
    			.buildSessionFactory();
    
    	// 要相使用SessionFactory.getCurrentSession()方法
    	// 需要在Hibernate主配置文件中配置current_session_context_class项。
    	// getCurrentSession()方法：
    	// >> 去指定的上下文中(如thread)查找绑定的Session对象,如果有就返回。
    	// >> 如果没有,就创建一个并绑定好,然后再返回
    	// >> openSession()只是开启一个新的Session,不会做绑定和查找操作。
    	@Test
    	public void testSession() throws Exception {
    		Session session1 = sessionFactory.getCurrentSession();
    		Session session2 = sessionFactory.getCurrentSession();
    
    		System.out.println(session1 != null);// true
    		System.out.println(session1 == session2);// true
    	}
    
    	// 当使用getCurrentSession时,Hibernate会在提交或回滚后自动的关闭Session
    	@Test
    	public void testSessionClose() throws Exception {
    		Session session = sessionFactory.getCurrentSession();
    		session.beginTransaction();
    
    		System.out.println("使用Session做xxx操作");
    
    		session.getTransaction().commit();
    		// session.close();//就不能再自已关闭了
    	}
    
    	@Test
    	public void testSession2() throws Exception {
    		Session session1 = sessionFactory.openSession();
    		Session session2 = sessionFactory.openSession();
    
    		System.out.println(session1 != null);// true
    		System.out.println(session1 == session2);// false
    	}
    
    	@Test
    	public void testSession3() throws Exception {
    		Session session1 = sessionFactory.openSession();
    		Session session2 = sessionFactory.getCurrentSession();
    
    		System.out.println(session1 != null);// true
    		System.out.println(session1 == session2);// false
    	}
    }

[Center]: /images/20220616/fa40b40022534d269bba0b1ae292f762.png