EntityManager的注入
第一步：服务器数据源发布
第二步：持久化单元配置
persistence.xml 放置到jar包的META-INF（强烈注意，千万不要用记事本写persistence.xml 就算另存为UTF-8的格式，记事本会默认在前面加一个你看不见的BOM头，而发布时JBOSS解析XML是不认识它的。所以正确的做法是在eclipse中创建persistence.xml，然后再黏贴过去文本 就不会出问题了，我在这个地方栽过）
<?xml version="1.0" encoding="UTF-8"?>
<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="mysql_pu" transaction-type="JTA">
<jta-data-source>java:MySqlDS</jta-data-source>
<properties>
<property name="hibernate.hbm2ddl.auto" value="update" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.format_sql" value="true" />
</properties>
</persistence-unit>
</persistence>
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ANT （其实eclipse就可以 帮我们打包工程了，所以我一般不用ANT，eclipse自己会用它自己的ANT）
build.xml
<?xml version="1.0"?>
<project name="EJB_JTA" default="ejbjar" basedir=".">
<property environment="env" />
<property name="src.dir" value="${basedir}/src" />
<property name="jboss.home" value="${env.JBOSS_HOME}" />
<property name="jboss.server.config" value="default" />
<property name="build.dir" value="${basedir}/build" />
<!-- Build classpath -->
<path id="build.classpath">
<fileset dir="${jboss.home}/client">
<include name="*.jar" />
</fileset>
<pathelement location="${build.dir}" />
</path>
<target name="undeploy" description="卸载EJB">
<delete file="${jboss.home}/server/${jboss.server.config}/deploy/${ant.project.name}.jar"/>
</target>
<target name="prepare" depends="undeploy">
<delete dir="${build.dir}"/>
<mkdir dir="${build.dir}" />
</target>
<target name="compile" depends="prepare" description="编绎">
<javac srcdir="${src.dir}" destdir="${build.dir}">
<classpath refid="build.classpath" />
</javac>
<!-- -->
<copy file="${src.dir}/META-INF/persistence.xml" todir="${build.dir}/META-INF"/>
</target>
<target name="ejbjar" depends="compile" description="创建EJB发布包">
<jar jarfile="${basedir}/${ant.project.name}.jar" basedir="${build.dir}">
<fileset dir="build">
<include name="*"/>
</fileset>
</jar>
</target>
<target name="deploy" depends="ejbjar" description="发布EJB">
<copy file="${basedir}/${ant.project.name}.jar" todir="${jboss.home}/server/${jboss.server.config}/deploy" />
</target>
</project>
第三步：注入EntityManager （不是线程安全的）
@PersistenceContext(unitName="my_u") //推荐的方式，EJB容器负责EntityManager 的生命周期
protected EntityManager entityManager;
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@PersistenceUnit(unitName="my_u")
protected EntityManagerFactory entityManagerFactory;
@PostConstruct
EntityManager entityManager=entityManagerFactory .createEntityManager();
@PreDestroy
entityManager.close();