EJB6: EntityBean例子
????? 本例子描述向EJB容器（JBoss）部署http://kylinsoong.iteye.com/blog/824676中描述的例子的全过程，链接博客中描述的例子包含7个实体：User、Event、Friend、Property、Pet、UserCard、Wife，其中：User和Event，User和Friend，Event和Property，Wife和Pet，Pet和Property关系为一对多关系；而User和UserCard，Friend和UserCard，Wife和UserCard，User和Wife之间的关系是一对一关系；
下面开始部署http://kylinsoong.iteye.com/blog/824676中描述的例子：
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1 JBoss数据源的配置
????? 数据源的备份文件可以在JBOSS_Home\docs\examples\jca下找到，我用的是Oracle10g所以我用到的JBoss数据源的配置JBOSS_Home\docs\examples\jca下的oracle-ds.xml，将oracle-ds.xml做一下修改，修改完拷贝到JBOSS_Home\server\production\deploy下，修改完的oracle-ds.xml的内容如下：
<?xml version="1.0" encoding="UTF-8"?><datasources> <local-tx-datasource> <jndi-name>OracleDS</jndi-name> <connection-url>jdbc:oracle:thin:@192.168.68.120:1521:orcl</connection-url> <driver-class>oracle.jdbc.driver.OracleDriver</driver-class> <user-name>***</user-name> <password>***</password> <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.OracleExceptionSorter</exception-sorter-class-name> <metadata> <type-mapping>Oracle10g</type-mapping> </metadata> </local-tx-datasource></datasources>
?其中说明了JBoss数据源的jndi-name：OracleDS，jndi-name必须唯一；
?????????????????????????????????????????连接URL：jdbc:oracle:thin:@192.168.68.120:1521:orcl
?????????????????????????????????? 连接驱动名称：oracle.jdbc.driver.OracleDriver
以及数据库名称及密码，数据库类型；
拷贝完成后启动JBoss，http://localhost:8080/jmx-console/HtmlAdaptor?action=displayMBeans下jboss.jca可以看到刚才添加数据源的配置信息：
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2 Bean开发
首先修改之前POJO实体，让其手实现java.io.Serializable接口，
其次用一个无状态Session Bean来控制Entity Bean
贴出Remote接口UserService和无状态SessionBean：UserServiceBean
public interface UserService {public void insertUser(User user);public void updateName(String newname, Long id);public void mergeUser(User user);public void deleteUser(Long id);public User getUserByID(Long id);public List<User> getUserList();}?
@Stateless@Remote(UserService.class)public class UserServiceBean implements UserService {@PersistenceContext(unitName="com.tibco.hibernate.po") protected EntityManager em;public void insertUser(User user) {em.persist(user);}public void updateName(String name, Long id) {User user = em.find(User.class, id);if(user != null){user.setName(name);}}public void mergeUser(User user) {em.merge(user);}public void deleteUser(Long id) {User user = em.find(User.class, id);if(user != null){em.remove(user);}}public User getUserByID(Long id) {return em.find(User.class, id);}public List<User> getUserList() {Query query = em.createQuery("select u from User as u");return query.getResultList();}}????? 如上：Remote接口UserService提供了一套对User的增删改查方法，无状态SessionBean类UserServiceBean分别提供了这些方法的一个实现。
@PersistenceContext(unitName="com.tibco.hibernate.po") 指定了Persistence unit的名字，容器通过这个名字可以找到相应的实体类和数据源等
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3. persistence.xml编写
????? 我们知道Persistence unit 是在persistence.xml中定义的，实体类型之所以能被EntityManager控制是因为提供了Persistence unit，根据持久化规范的要求，该描述文件是必须提供的，如果不提供这一文件，则Persistence unit也
?将不存在，因此应用也不能够获得和使用EntityManager，下面是persistence.xml内容：
<?xml version="1.0"?><persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0"> <persistence-unit name="com.tibco.hibernate.po"> <jta-data-source>java:/OracleDS</jta-data-source> <properties> <property name="hibernate.hbm2ddl.auto" value="create-drop"/> <!-- 调整JDBC抓取数量的大小: Statement.setFetchSize() --> <property name="hibernate.jdbc.fetch_size" value="18"/> <!-- 调整JDBC批量更新数量 --> <property name="hibernate.jdbc.batch_size" value="10"/> <!-- 显示最终执行的SQL --> <property name="hibernate.show_sql" value="true"/> <!-- 格式化显示的SQL --> <property name="hibernate.format_sql" value="true"/> </properties> </persistence-unit></persistence>
?配置文件说明我们用的JPA的实现是Hibernate，“hibernate.hbm2ddl.auto”值得容器启动时创建表，容器关闭时删除表，"hibernate.show_sql"在容器Console口打印SQL语句，"hibernate.format_sql"说明在容器Console显示的SQL语句是格式化的；
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4 将过程打包部署到JBOSS_Home\server\production\deploy下
我们用Ant实现，关于Ant参考http://kylinsoong.iteye.com/admin/blogs/787097这里直接给出build.xml
<?xml version="1.0"?><project name="com.tibco.hibernate" default="deploy" basedir=".."><property environment="env" /><property name="app.dir" value="${basedir}\com.tibco.hibernate" /><property name="src.dir" value="${app.dir}\src" /><property name="jboss.home" value="${env.JBOSS_HOME}" /><property name="jboss.server.config" value="production" /><property name="build.dir" value="${app.dir}\build" /><property name="build.classes.dir" value="${build.dir}\classes" /><!-- Build classpath --><path id="build.classpath"><fileset dir="${jboss.home}\client"><include name="*.jar" /></fileset><fileset dir="${jboss.home}\client\userService"><include name="*.jar" /></fileset><pathelement location="${build.classes.dir}" /></path><target name="prepare" depends="clean"><mkdir dir="${build.dir}" /><mkdir dir="${build.classes.dir}" /></target><target name="compile" depends="prepare" description="compile"><javac srcdir="${src.dir}" destdir="${build.classes.dir}" debug="on" deprecation="on" optimize="off" includes="com/**"><classpath refid="build.classpath" /></javac></target><target name="ejbjar" depends="compile" description="ejbjar"><jar jarfile="${app.dir}\UserBean.jar"><fileset dir="${build.classes.dir}"><include name="com/tibco/hibernate/po/*.class" /><include name="com/tibco/hibernate/po/bean/*.class" /></fileset><metainf dir="${src.dir}\META-INF"><include name="persistence.xml" /></metainf></jar></target><target name="deploy" depends="ejbjar"><copy file="${app.dir}\UserBean.jar" todir="${jboss.home}\server\${jboss.server.config}\deploy" /></target><!-- =================================================================== --><!-- Cleans up generated stuff --><!-- =================================================================== --><target name="clean"><delete dir="${build.dir}" /><delete file="${jboss.home}\server\${jboss.server.config}\deploy\UserBean.jar" /></target></project>?运行Ant，文件部署成功
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5 测试
运行这段代码可以插入一条数据并查询：
public static void main(String[] args) throws NamingException {Properties properties = new Properties();properties.setProperty(Context.INITIAL_CONTEXT_FACTORY , "org.jnp.interfaces.NamingContextFactory"); properties.setProperty(Context.PROVIDER_URL, "jnp://localhost"); Context ctx = new InitialContext(properties); UserService userService = (UserService) ctx.lookup("UserServiceBean/remote"); User user = JPAClient.getUser();userService.insertUser(user); for(User u : userService.getUserList()) { System.out.println("id:" + u.getId() + " name:" + u.getName()); }}?
当然我们也可以运用反射修改刚才插入的user：
public static void main(String[] args) throws NamingException, IllegalArgumentException, IllegalAccessException, InvocationTargetException {Properties properties = new Properties();properties.setProperty(Context.INITIAL_CONTEXT_FACTORY , "org.jnp.interfaces.NamingContextFactory"); properties.setProperty(Context.PROVIDER_URL, "jnp://localhost"); Context ctx = new InitialContext(properties); Object obj = ctx.lookup("UserServiceBean/remote"); for(Method m : obj.getClass().getMethods()) { if(m.getName().compareTo("updateName") == 0){ m.invoke(obj, new Object[]{"Kobe Bryant", new Long(1)}); } } for(Method m : obj.getClass().getMethods()) { if(m.getName().compareTo("getUserByID") == 0) { User user = (User) m.invoke(obj, new Object[]{new Long(1)}); System.out.println(user.getName()); } }}?
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