Spring访问EJB3.0的SessionBean方法

Spring2.*提供了一个访问EJB的方法，即

“org.springframework.ejb.access.LocalStatelessSessionProxyFactoryBean”和

“org.springframework.ejb.access.SimpleRemoteStatelessSessionProxyFactoryBean”

两个FactoryBean,一个用来访问本地的，一个用来访问远程的无状态SessionBean。但是这两个FactoryBean

只能针对EJB2.0的无状态SessionBean，所以在配置是必须提供SessionBean的Home接口。而在EJB3.0中已经没有了Home接口（或者说被隐藏起来了）。为了访问EJB3.0的无状态Session Bean就只好自己写一个了。

 package com.cyf.spring.ext;



 import javax.naming.Context;
 import javax.naming.InitialContext;
 import javax.naming.NamingException;

 import org.apache.log4j.Logger;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.jndi.JndiTemplate;

 public class SlsbFactoryBean implements FactoryBean {

    private static Logger log=Logger.getLogger(SlsbFactoryBean.class);
    private JndiTemplate jndiTemplate;
     private Context ejbCtx;
     private String jndiName;
     private Object ejbobj;
     public synchronized Object getEjbObject(){
         if (ejbobj==null){
             if (jndiTemplate == null || jndiTemplate.getEnvironment() == null) {
                 throw new LookupSlsbException("jndiTemplate is required!");
             }
             try {
                 ejbCtx = new InitialContext(jndiTemplate.getEnvironment());
             } catch (Exception e) {
                 throw new LookupSlsbException(
                         "can't initial a javax.naming.InitialContext ");
             }
             if (jndiName==null){
                 throw new LookupSlsbException("jndiName is required!");
             }
             try {
                 ejbobj=ejbCtx.lookup(jndiName);
                 return ejbobj;
             } catch (NamingException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
                 return null;
             }
         }else{
             return ejbobj;
         }
     }
     public Object getObject() throws Exception {
         // TODO Auto-generated method stub
         return getEjbObject();
     }

     public Class getObjectType() {
         // TODO Auto-generated method stub
         return null;
     }

     public boolean isSingleton() {
         // TODO Auto-generated method stub
         return false;
     }

     public JndiTemplate getJndiTemplate() {
         return jndiTemplate;
     }

     public void setJndiTemplate(JndiTemplate jndiTemplate) {
         log.info("setting jndiTemplate....");
         this.jndiTemplate = jndiTemplate;
     }

     public String getJndiName() {
         return jndiName;
     }

     public void setJndiName(String jndiName) {
         log.info("setting jndiName");
         this.jndiName = jndiName;
     }


 }

这个类实现了Spring的FactoryBean接口

 /*
  * Copyright 2002-2007 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package org.springframework.beans.factory;

 /**
  * Interface to be implemented by objects used within a {@link BeanFactory}
  * which are themselves factories. If a bean implements this interface,
  * it is used as a factory for an object to expose, not directly as a bean
  * instance that will be exposed itself.
  *
  * <p><b>NB: A bean that implements this interface cannot be used as a
  * normal bean.</b> A FactoryBean is defined in a bean style, but the
  * object exposed for bean references is always the object that it creates.
  *
  * <p>FactoryBeans can support singletons and prototypes, and can
  * either create objects lazily on demand or eagerly on startup.
  *
  * <p>This interface is heavily used within the framework itself, for
  * example for the AOP {@link org.springframework.aop.framework.ProxyFactoryBean}
  * or the {@link org.springframework.jndi.JndiObjectFactoryBean}.
  * It can be used for application components as well; however,
  * this is not common outside of infrastructure code.
  *
  * @author Rod Johnson
  * @author Juergen Hoeller
  * @since 08.03.2003
  * @see org.springframework.beans.factory.BeanFactory
  * @see org.springframework.aop.framework.ProxyFactoryBean
  * @see org.springframework.jndi.JndiObjectFactoryBean
  */
 public interface FactoryBean {

     Object getObject() throws Exception;


     Class getObjectType();


     boolean isSingleton();

 }

请注意FactoryBean的“getObject()”方法，这个方法将会在Spring客户端调用ApplicationContext.getBean()的时候被调用，或者说getObject()代理了getBean()方法，下面将会看一个例子。所以我在getObject()方法中去lookup EJB3.0的sessionbean。

再来看下Spring配置文件。

 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd">
     <bean id="propertyConfigurer"
         class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
         <property name="location">
             <value>WEB-INF/classes/jndi.properties</value>
         </property>
     </bean>
     <bean id="jndiTemplate"
         class="org.springframework.jndi.JndiTemplate">
         <property name="environment">
             <props>
                 <prop key="java.naming.provider.url">
                     ${java.naming.provider.url}
                 </prop>
                 <prop key="java.naming.factory.initial">
                     ${java.naming.factory.initial}
                 </prop>
                 <prop key="java.naming.factory.url.pkgs">
                     ${java.naming.factory.url.pkgs}
                 </prop>
             </props>
         </property>
     </bean>
     <bean id="RemoteDAO" class="com.cyf.spring.ext.SlsbFactoryBean">
         <property name="jndiTemplate">
             <ref local="jndiTemplate" />
         </property>
         <property name="jndiName" value="CommonDAOImpl/remote" />
     </bean>
 </beans>

SlsbFactoryBean只需要设置jndi属性模板和jndiName，不需要EJB2.0的home接口了

调用的例子：

 package com.cyf.spring.ext;

 import java.util.List;

 import javax.faces.context.FacesContext;

 import org.apache.log4j.Logger;
 import org.springframework.context.ApplicationContext;
 import org.springframework.web.jsf.FacesContextUtils;

 import com.book.business.CommonDAO;
 import com.bookstore.admin.actions.PressAction;

 public class TestSlsbFactoryBean {
  //在JSF环境中得到SpringApplicationContext
  private static ApplicationContext ctx = FacesContextUtils
    .getWebApplicationContext(FacesContext.getCurrentInstance());
  private static Logger log = Logger.getLogger(TestSlsbFactoryBean.class);

  public void testBean() {
   //getBean(RemoteDAO)返回的结果就是调用SlsbFactoryBean.getObject()方法返回的结果
   CommonDAO dao = (CommonDAO)ctx.getBean("RemoteDAO");
   List list = dao.getObjByEQL("select count(p) from Press p", null, -1, -1);
   long size = (Long) list.get(0);
   log.info(size);
  }
 }