ejb2.0 HelloWord[转]

ejb2.0 HelloWord

http://8366.iteye.com/blog/247315

关键字: ejb

   中国电信网上营业厅项目是使用ejb2.0开发的,在项目中已有的框架中修修补补,也没写过一个HelloWorld的例子,今天朝花夕拾,写一个例子

 

步骤:

 

1.在eclipse下新建一个java项目.命名叫 ejb2test

2.在项目的根目录下建立  META-INF 文件夹,主要是为了存放ejb-jar.xml, jboss.xml

3.在src文件夹下建立 两个包 cn.com.xinli.ejb  ,cn.com.xinli.test

4.到入需要的jar包到classpath中, jboss-j2ee.jar,这个jar包可以在 %jbossHome%\server\default\lib中找到

5.下面开始写代码,一个ejb需要写两个接口和一个实现类.

 

在cn.com.xinli.ejb

 

先写本地接口 HelloWorldHome.java

package cn.com.xinli.ejb;
 import java.rmi.RemoteException;
 import javax.ejb.CreateException;
 import javax.ejb.EJBHome;
 public interface HelloWorldHome extends EJBHome
{
     HelloWorldRemote create() throws RemoteException, CreateException;
}

package cn.com.xinli.ejb;
import java.rmi.RemoteException;
import javax.ejb.CreateException;
import javax.ejb.EJBHome;
public interface HelloWorldHome extends EJBHome
{
	HelloWorldRemote create() throws RemoteException, CreateException;
}

 

远程接口:  HelloWorldRemote.java

 

package cn.com.xinli.ejb;

 import java.rmi.RemoteException;

 import javax.ejb.EJBObject;

 public interface HelloWorldRemote extends EJBObject
{
     String sayHello() throws RemoteException;

}

package cn.com.xinli.ejb;

import java.rmi.RemoteException;

import javax.ejb.EJBObject;

public interface HelloWorldRemote extends EJBObject
{
	String sayHello() throws RemoteException;

}

 

 

 实现Bean类:HelloWorldBean.java (必须有会话bean的5个状态,可以为空实现,和远程接口中要实现的方法,网厅项目中是又把实现方法写在一个类里,每次 new一个类的对象,返回一个实现方法给Bean)

 

package cn.com.xinli.ejb;

 import java.rmi.RemoteException;

 import javax.ejb.EJBException;
 import javax.ejb.SessionBean;
 import javax.ejb.SessionContext;


 public class HelloWorldBean implements SessionBean
{

      public void setSessionContext(SessionContext arg0) throws EJBException, RemoteException
        {
             System.out.println("set session context");

        }

         public void ejbCreate() throws EJBException
        {
             System.out.println("ejb create");

        }

         public void ejbRemove() throws EJBException, RemoteException
        {
             System.out.println("ejb remove");
        }

         public void ejbActivate() throws EJBException, RemoteException
        {
             System.out.println("ejb activate");
        }

         public void ejbPassivate() throws EJBException, RemoteException
        {
             System.out.println("ejb passivate");
        }

         public String sayHello() throws RemoteException
        {
             return "Welecome to ejb2.0,HXL";
        }

    }

package cn.com.xinli.ejb;

import java.rmi.RemoteException;

import javax.ejb.EJBException;
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;


public class HelloWorldBean implements SessionBean
{
	
	 public void setSessionContext(SessionContext arg0) throws EJBException, RemoteException
	    {
	        System.out.println("set session context");
	        
	    }
	    
	    public void ejbCreate() throws EJBException
	    {
	        System.out.println("ejb create");
	        
	    }

	    public void ejbRemove() throws EJBException, RemoteException
	    {
	        System.out.println("ejb remove");
	    }

	    public void ejbActivate() throws EJBException, RemoteException
	    {
	        System.out.println("ejb activate");
	    }

	    public void ejbPassivate() throws EJBException, RemoteException
	    {
	        System.out.println("ejb passivate");
	    }

	    public String sayHello() throws RemoteException
	    {
	        return "Welecome to ejb2.0,HXL";
	    }

	}

 

 

 6.写配置文件在META-INF 目录下,这个目录的名字不能改变(这里我们是一个有状态的回话bean)

 

ejb-jar.xml

 

 

 

<?xml version="1.0" encoding="gb2312"?>
<!DOCTYPE ejb-jar PUBLIC "-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 2.0//EN"
 "http://java.sun.com/dtd/ejb-jar_2_0.dtd">

 <ejb-jar>
     <description>ejb</description>
     <display-name>myEJBTest</display-name>

     <enterprise-beans>
         <session>
             <display-name>helloEJB</display-name>
             <ejb-name>helloEJB</ejb-name>
             <home>cn.com.xinli.ejb.HelloWorldHome</home>
             <remote>
                cn.com.xinli.ejb.HelloWorldRemote
             </remote>
             <ejb-class>
                cn.com.xinli.ejb.HelloWorldBean
             </ejb-class>
             <session-type>Stateful</session-type>
             <transaction-type>Bean</transaction-type>
         </session>
     </enterprise-beans>
 </ejb-jar>

<?xml version="1.0" encoding="gb2312"?> 
<!DOCTYPE ejb-jar PUBLIC "-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 2.0//EN" 
"http://java.sun.com/dtd/ejb-jar_2_0.dtd">

<ejb-jar>
	<description>ejb</description>
	<display-name>myEJBTest</display-name>

	<enterprise-beans>
		<session>
			<display-name>helloEJB</display-name>
			<ejb-name>helloEJB</ejb-name>
			<home>cn.com.xinli.ejb.HelloWorldHome</home>
			<remote>
				cn.com.xinli.ejb.HelloWorldRemote
			</remote>
			<ejb-class>
				cn.com.xinli.ejb.HelloWorldBean
			</ejb-class>
			<session-type>Stateful</session-type>
			<transaction-type>Bean</transaction-type>
		</session>
	</enterprise-beans>
</ejb-jar>

 

 

 jboss.xml  (其中)<jndi-name>元素的值必须在容器中唯一

 

 

 

<?xml version="1.0" encoding="gb2312"?>

 <jboss>
     <enterprise-beans>
         <session>
             <ejb-name>helloEJB</ejb-name>
             <jndi-name>ejb/helloEJB</jndi-name>
         </session>
     </enterprise-beans>
 </jboss>

<?xml version="1.0" encoding="gb2312"?>

<jboss>
	<enterprise-beans>
		<session>
			<ejb-name>helloEJB</ejb-name>
			<jndi-name>ejb/helloEJB</jndi-name>
		</session>
	</enterprise-beans>
</jboss>

 

 

7.把项目打成jar包发布在ejb容器中,我使用的是Jboss,大包后放在 %JbossHome%\server\default\deploy下

 

打包我们可以用eclipse ,在项目上点右键->Export->Jar File->  记得要选择generate 就可以了,也可以使用 jar cvf 命令来打jar包

8.启动Jboss,我们会看到我们发布的ejb,如果没有错误的话

 

9.下面我们写一个测试,首先我们要导入 jboss-client.jar 到classpath 下,这个jar包在 %JbossHome%\client下

 

Test.java

 

package cn.com.xinli.ejb.test;

 import java.util.Properties;

 import javax.naming.InitialContext;
 import javax.rmi.PortableRemoteObject;

 import org.apache.log4j.Logger;

 import cn.com.xinli.ejb.HelloWorldHome;
 import cn.com.xinli.ejb.HelloWorldRemote;

 public class Test
{

     static Logger log=Logger.getLogger(Test.class);
     /**
     * @param args
     */
     public static void main(String[] args)
    {

         System.out.println("===========================================================");
         Properties props = new Properties();
         props.setProperty("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory");
         props.setProperty("java.naming.provider.url", "localhost:1099");
         props.setProperty("java.naming.factory.url.pkgs", "org.jboss.naming");
         try
        {
             InitialContext ctx = new InitialContext(props);

             Object objRef = ctx.lookup("ejb/helloEJB");

             HelloWorldHome home = (HelloWorldHome) PortableRemoteObject.narrow(objRef, HelloWorldHome.class);

            HelloWorldRemote remote = home.create();

            log.info(remote.sayHello());
        }
         catch (Exception ex)
        {
            ex.printStackTrace();
        }
    }
}

package cn.com.xinli.ejb.test;

import java.util.Properties;

import javax.naming.InitialContext;
import javax.rmi.PortableRemoteObject;

import org.apache.log4j.Logger;

import cn.com.xinli.ejb.HelloWorldHome;
import cn.com.xinli.ejb.HelloWorldRemote;

public class Test
{

	static Logger log=Logger.getLogger(Test.class);
	/**
	 * @param args
	 */
	public static void main(String[] args)
    {
		
        System.out.println("===========================================================");
        Properties props = new Properties();
        props.setProperty("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory");
        props.setProperty("java.naming.provider.url", "localhost:1099");
        props.setProperty("java.naming.factory.url.pkgs", "org.jboss.naming");
        try
        {
            InitialContext ctx = new InitialContext(props);
            
            Object objRef = ctx.lookup("ejb/helloEJB");
            
            HelloWorldHome home = (HelloWorldHome) PortableRemoteObject.narrow(objRef, HelloWorldHome.class);
            
            HelloWorldRemote remote = home.create();
            
            log.info(remote.sayHello());
        }
        catch (Exception ex)
        {
            ex.printStackTrace();
        }
    }
}

 

 

 

 10.结果:

 

===========================================================
0    [main] INFO  cn.com.xinli.ejb.test.Test(38) - Welecome to ejb2.0,HXL

 

 

 到此,我们就完成了一个ejb2.0 HelloWorld 的开发

 

 在ejb-jar.xml 中,我们将<session-type> </session-type> 元素的值修改为Stateless,就是一个无状态的回话bean了,无状态的会话bean也是使用的最多的bean了. 

 

 

 

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