Spring访问EJB3.0的SessionBean步骤

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 blocke.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 stubreturn null;}public boolean isSingleton() {// TODO Auto-generated method stubreturn 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"/></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); }}

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