java - 在基于 Spring MVC 的应用程序中，我应该何时何地从 hibernate 4.3.8.Final 获取新 session ？

Question

我已经为我的 Spring 应用程序配置了 Hibernate。我有一个名为 hibernateUtil.java 的文件，它为 Hibernate 创建一个新 session 。问题是我什么时候应该调用它的 getSession 方法？有没有更好的方法？

Hibernate.cfg.xml

<?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>

        <!-- Database connection settings -->
        <property name="connection.driver_class">
            com.mysql.jdbc.Driver
        </property>
        <property name="connection.url">
            jdbc:mysql://localhost:3306/mydb
        </property>
        <property name="connection.username">root</property>
        <property name="connection.password"></property>

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">12</property>

        <!-- SQL dialect -->
        <property name="dialect">
            org.hibernate.dialect.MySQLDialect
        </property>

        <property name="current_session_context_class">thread</property>


        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>

        <!-- Drop and re-create the database schema on startup -->
        <property name="hbm2ddl.auto">update</property>

        <mapping class="com.myproject.model.business" />




    </session-factory>

</hibernate-configuration>

HibernateUtil.java

import org.hibernate.HibernateException;
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 HibernateUtil {

    private static ServiceRegistry serviceRegistry;
    private static final ThreadLocal<Session> threadLocal = new ThreadLocal();
    private static SessionFactory sessionFactory;


    private static SessionFactory configureSessionFactory() {
        try {
            Configuration configuration = new Configuration();
            configuration.configure();
            serviceRegistry = new StandardServiceRegistryBuilder()
                    .applySettings(configuration.getProperties()).build();
            sessionFactory = configuration.buildSessionFactory(serviceRegistry);
            return sessionFactory;
        } catch (HibernateException e) {
            e.printStackTrace();
        }
        return sessionFactory;
    }

    static {
        try {
            sessionFactory = configureSessionFactory();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private HibernateUtil() {
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    public static Session getSession() throws HibernateException {
        Session session = threadLocal.get();

        if (session == null || !session.isOpen()) {
            if (sessionFactory == null) {
                rebuildSessionFactory();
            }
            session = (sessionFactory != null) ? sessionFactory.openSession()
                    : null;
            threadLocal.set(session);
        }

        return session;


    }


    public static void rebuildSessionFactory() {
        try {
            sessionFactory = configureSessionFactory();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void closeSession() throws HibernateException {
        Session session = (Session) threadLocal.get();
        threadLocal.set(null);

        if (session != null) {
            if (session.isOpen()) {
                session.close();
            }
        }
    }
}

我还发现了这个tutorial但我不确定它是否可靠。建议使用 Spring bean 配置文件进行 Hibernate 配置。

Answer 1

如果您的应用程序是使用 java servlet 的 Web 应用程序，您可以添加一个 servlet 请求过滤器，您可以在其中启动 session 甚至事务。然后可以使用同一个类来提交事务和刷新/关闭 session 。 例如(没有错误处理):

import javax.servlet.*;

public class HibernateSessionRequestFilter implements Filter {

public void doFilter(ServletRequest request, ServletResponse response,
                  FilterChain chain) throws IOException, ServletException {

    Session session=HibernateUtil.getSession();
    session.beginTransaction();

    // Call the next filter (continue request processing)
    chain.doFilter(request, response);

    session.flush();
    session.getTransaction().commit();
}