如何在创建Hibernate会话时拦截它们(Spring/Grails环境)

Question

有没有办法在创建新的Hibernate会话时拦截它们？我需要访问每个Session实例以启用带参数的Hibernate过滤器.

我工作的唯一解决方案涉及包装SessionFactory,但这涉及很多半讨厌的黑客,并且它要求我实现大约60种方法,其中只有少数是有趣的.

Hibernate的SessionFactory实现是出于某种令人烦恼的原因而宣布为final,因此扩展它不是一种选择.我也试过方面和Java代理没有任何运气.

Answer 1

我能够创建一个JDK代理:

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Date;

import org.hibernate.SessionFactory;
import org.hibernate.engine.SessionFactoryImplementor;

public class SessionFactoryProxyCreator {

   public static SessionFactory instance;

   public static SessionFactory createProxy(final SessionFactory realSessionFactory) {
      ClassLoader cl = SessionFactory.class.getClassLoader();
      Class<?>[] interfaces = new Class[] { SessionFactory.class, SessionFactoryImplementor.class };
      instance = (SessionFactory)Proxy.newProxyInstance(cl, interfaces, new InvocationHandler() {
         public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {

            if ("openSession".equals(method.getName())) {
               System.out.println("NEW SESSION AT " + new Date());
            }

            return method.invoke(realSessionFactory, args);
         }
      });

      return instance;
   }
}

你可以从自定义SessionFactoryBean中调用它:

import org.codehaus.groovy.grails.orm.hibernate.ConfigurableLocalSessionFactoryBean;
import org.hibernate.HibernateException;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class MyConfigurableLocalSessionFactoryBean extends ConfigurableLocalSessionFactoryBean {

   public MyConfigurableLocalSessionFactoryBean() {
      setCurrentSessionContextClass(MyCurrentSessionContext.class);
   }

   @Override
   protected SessionFactory buildSessionFactory() throws Exception {
      setExposeTransactionAwareSessionFactory(false);
      return SessionFactoryProxyCreator.createProxy(super.buildSessionFactory());
   }

   @Override
   protected SessionFactory newSessionFactory(Configuration config) throws HibernateException {
      setExposeTransactionAwareSessionFactory(false);
      return SessionFactoryProxyCreator.createProxy(super.newSessionFactory(config));
   }
}

这取决于使用代理而不是真实会话工厂的Spring的SpringSessionContext的修改版本:

import org.hibernate.HibernateException;
import org.hibernate.classic.Session;
import org.hibernate.context.CurrentSessionContext;
import org.hibernate.engine.SessionFactoryImplementor;
import org.springframework.orm.hibernate3.SessionFactoryUtils;

public class MyCurrentSessionContext implements CurrentSessionContext {

   public MyCurrentSessionContext(SessionFactoryImplementor sessionFactory) {
      // ignore the real sessionFactory, need to use the proxy
   }

   public Session currentSession() throws HibernateException {
      try {
         return (org.hibernate.classic.Session)SessionFactoryUtils.doGetSession(
               SessionFactoryProxyCreator.instance, false);
      }
      catch (IllegalStateException e) {
         throw new HibernateException(e.getMessage());
      }
   }
}

这需要在resources.groovy中注册,以替换标准的Grails ConfigurableLocalSessionFactoryBean:

import org.codehaus.groovy.grails.commons.ApplicationHolder as AH
import org.codehaus.groovy.grails.orm.hibernate.events.PatchedDefaultFlushEventListener

beans = {

   sessionFactory(MyConfigurableLocalSessionFactoryBean) {

      def ds = AH.application.config.dataSource
      def hibConfig = AH.application.config.hibernate

      dataSource = ref('dataSource')
      List hibConfigLocations = []
      if (AH.application.classLoader.getResource('hibernate.cfg.xml')) {
         hibConfigLocations << 'classpath:hibernate.cfg.xml'
      }
      def explicitLocations = hibConfig?.config?.location
      if (explicitLocations) {
         if (explicitLocations instanceof Collection) {
            hibConfigLocations.addAll(explicitLocations.collect { it.toString() })
         }
         else {
            hibConfigLocations << hibConfig.config.location.toString()
         }
      }
      configLocations = hibConfigLocations
      if (ds?.configClass) {
         configClass = ds.configClass
      }
      hibernateProperties = ref('hibernateProperties')
      grailsApplication = ref('grailsApplication', true)
      lobHandler = ref('lobHandlerDetector')
      entityInterceptor = ref('entityInterceptor')
      eventListeners = ['flush': new PatchedDefaultFlushEventListener(),
                        'pre-load':    ref('eventTriggeringInterceptor'),
                        'post-load':   ref('eventTriggeringInterceptor'),
                        'save':        ref('eventTriggeringInterceptor'),
                        'save-update': ref('eventTriggeringInterceptor'),
                        'post-insert': ref('eventTriggeringInterceptor'),
                        'pre-update':  ref('eventTriggeringInterceptor'),
                        'post-update': ref('eventTriggeringInterceptor'),
                        'pre-delete':  ref('eventTriggeringInterceptor'),
                        'post-delete': ref('eventTriggeringInterceptor')]
   }
}