Maven2上第一个EJB2.1简单实例

Maven2下第一个EJB2.1简单实例

????????一开始还是得列出Maven2下EJB2.1的目录结构，详细介绍请参照我之前写的一篇文章 [ Maven2下第一个EJB3.0简单实例 ]，之所以将EJB2.1的实例与EJB3.0的实例写到一起，是因为确实两个版本变化较大，也是因为很多人确实遇到要从EJB2.1跳转到EJB3.0的情况，就是说要把以前EJB2.1的改写成EJB3.0的，这样的话，肯定需要有一个开始，万事开头难，搞技术一点也例外不了，有些就是在一开始的时候做个简单实例都要花上好长一段时间，反而在做出简单实例后，之后的工作进展就快许多，所以我将这两篇文章摆到一起，有需要就看吧，没需要也不影响。

ejb2test

??? |--pom.xml???????????????????????????????????????????????? //Maven项目根目录必须有这文件，主配置文件来的

??? |--src???????????????????????????????????????????????????????? //项目资源文件目录，所有代码，项目相关的都在这

??????? |--main????????????????????????????????????????????????? //主文件目录，与之相对应的是单元测试test目录

??????????? |--java?????????????????????????????????????????????? //JAVA文件目录，使之与图片，配置文件等隔离开来

??????????????? |--mydomain???????????????????????????????? //这下面就是你自己的东西，不一一介绍了

??????????????????? |--ejb2test

??????????????????????? |--HaiRemoteHome.java?????? //EJB2需要一个或两个Home文件，用来返回EJBObject

??????????????????????? |--HaiRemote.java??????????????? //Remote接口，相对应的是Local接口，二选一或二全选

??????????????????????? |--HaiBean.java??????????????????? //这个才是主角，SessionBean文件，里面才有实现方法

????????????|--resources????????????????????????????????????? //资源文件，像一些配置文件全放这，图片也放这

??????????????? |--META-INF

??????????????????? |--ejb-jar.xml????????????????????????????

??????????????????? |--jboss.xml

????????|--test??????????????????????????????????????????????????? //单元测试目录，与主目录main相隔离，可不要这文件夹

??????????? |--java?????????????????????????????????????????????? //下面这些目录与main里面的java目录一模一样，对应的

??????????????? |--mydomain

??????????????????? |--ejb2test

下面是整个pom文件，全贴出来了

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
??? <modelVersion>4.0.0</modelVersion>
??? <groupId>com.mydomain</groupId>
??? <artifactId>ejb2.1</artifactId>
??? <packaging>jar</packaging>
??? <version>1.0-SNAPSHOT</version>
??? <name>ejb2 Maven Webapp</name>
??? <url>http://maven.apache.org</url>
??? <dependencies>
??????? <dependency>
??????????? <groupId>junit</groupId>
??????????? <artifactId>junit</artifactId>
??????????? <version>3.8.1</version>
??????????? <scope>test</scope>
??????? </dependency>

?????? 
??????? <dependency>
??????????? <groupId>jboss</groupId>
??????????? <artifactId>jboss-j2ee</artifactId>
??????????? <version>4.0.2</version>
??????? </dependency>
??? </dependencies>
??? <build>
??????? <finalName>ejb2</finalName>
??????? <plugins>
??????????? <plugin>
??????????????? <artifactId>maven-compiler-plugin</artifactId>
??????????????? <version>2.0.2</version>
??????????????? <configuration>
??????????????????? <source>1.5</source>
??????????????????? <target>1.5</target>
??????????????????? <encoding>UTF-8</encoding>
??????????????? </configuration>
??????????? </plugin>
??????????? <plugin>
??????????????? <artifactId>maven-resources-plugin</artifactId>
??????????????? <version>2.2</version>
??????????????? <configuration>
??????????????????? <encoding>UTF-8</encoding>
??????????????? </configuration>
??????????? </plugin>
??????? </plugins>
??? </build>
</project>

下面是HaiRemoteHome，HaiRemote与HaiBean的源码

1、HaiRemoteHome.java

package com.mydomain;

import java.rmi.RemoteException;
import javax.ejb.CreateException;
import javax.ejb.EJBHome;

public interface HaiRemoteHome extends EJBHome
{
??? HaiRemote create() throws RemoteException, CreateException;
}

2、HaiRemote.java

package com.mydomain;

import java.rmi.RemoteException;
import javax.ejb.EJBObject;

public interface HaiRemote extends EJBObject
{
??? String sayHai() throws RemoteException;
}

3、HaiBean.java

package com.mydomain;

import java.rmi.RemoteException;
import javax.ejb.EJBException;
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;

public class HaiBean 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 sayHai() throws RemoteException
??? {
??????? return "Hai, EJB 2!";
??? }

}

下面是ejb-jar.xml与jboss.xml的内容

1、ejb-jar.xml

<?xml version="1.0" encoding="UTF-8"?>

<!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>Hai EJB instance.</description>
??? <display-name>Hai EJB</display-name>
??? <enterprise-beans>
??????? <session>
??????????? <ejb-name>HaiEJB</ejb-name>
??????????? <home>com.mydomain.HaiHome</home>
??????????? <remote>com.mydomain.HaiRemote</remote>
??????????? <ejb-class>com.mydomain.HaiBean</ejb-class>
??????????? <session-type>Stateful</session-type>
??????????? <transaction-type>Bean</transaction-type>
??????? </session>
??? </enterprise-beans>
</ejb-jar>

2、jboss.xml

<?xml version="1.0" encoding="UTF-8"?>

<jboss>
??? <enterprise-beans>
??????? <session>
??????????? <ejb-name>HaiEJB</ejb-name>
??????????? <jndi-name>HaiEJB</jndi-name>
??????? </session>
??? </enterprise-beans>
</jboss>

写完这些文件，就可以用mvn生成jar包了

mvn install

然后在项目根目录的target文件夹下，有一个ejb2.jar，将它复制到jboss文件夹下，server/default/deploy目录中，然后在命令行中运行jboss文件夹下的/bin/run.bat文件，这一过程通常称之为deploy

待deploy成功后，就可以写一个java application进行测试了

新建一个java application

导入jboss目录下client文件夹下的jboss-j2ee.jar，

然后新建一个类，写上以下代码

import com.mydomain.HaiHome;
import com.mydomain.HaiRemote;
import java.rmi.RemoteException;
import java.util.Properties;
import javax.ejb.CreateException;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.rmi.PortableRemoteObject;

public class Main
{
??? 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("HaiEJB");
???????????
??????????? HaiHome home = (HaiHome) PortableRemoteObject.narrow(objRef, HaiHome.class);
???????????
??????????? HaiRemote remote = home.create();
???????????
??????????? System.out.println(remote.sayHai());
??????? }
??????? catch (Exception ex)
??????? {
??????????? ex.printStackTrace();
??????? }
??? }
}

?如果顺利的话，你应该可以看到以下信息

Hai, EJB 2!

1 楼 liuyu220 2009-08-25 楼主，你讲了这么多，没有提及怎么将ejb2.1转换成3.0啊。还有我想问一下，可不可以在一个项目下同时开发ejb2.1和ejb3.0的程序？如果楼主知道，请多多的说，不胜感谢 2 楼 Gavin.Chen 2009-08-31 liuyu220 写道楼主，你讲了这么多，没有提及怎么将ejb2.1转换成3.0啊。还有我想问一下，可不可以在一个项目下同时开发ejb2.1和ejb3.0的程序？如果楼主知道，请多多的说，不胜感谢

2.1转3.0，怎么转没办法讲，你熟悉了这两个版本的规范，自然就知道怎么去改这些相关的类，不过这两个版本差别太大，将旧的2.1转向3.0代价很大，要从长考虑，况且现在3.0到现在还未完全稳定，如果是企业级应用，要小心用3.0

同时开发ejb2.1和ejb3.0是可以的，不要两个要分别打包成独立的jar包，总项目打包成ear包，把ejb2.1与ejb3.0的jar包都包含进去，再部署到容器里就可以了

Maven2上第一个EJB2.1简单实例

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