[英]Injected EntityManager null in java-ee batch job
我正在尝试使用注入的实体管理器来使用java-ee持久化批处理作业的输出,但是EntityManager始终为null。 我正在使用在glassfish上运行的Maven Web应用程序,并按以下方式安排作业。
@Stateless
public class Scheduler {
@Schedule(minute = "*/1", hour = "*")
public void runEveryMinute() {
JobOperator jobOperator = BatchRuntime.getJobOperator();
jobOperator.start("newOrderProcessJob", null);
}
}
在我的作家一步
@Named
public class OrderWriter extends AbstractItemWriter {
@PersistenceContext()
EntityManager em;
@Override
public void writeItems(List<Object> list){
for (Object p : list) {
em.merge(p);
}
}
}
还有我的persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="com.mycompany_mavenproject1_war_1.0-SNAPSHOTPU" transaction-type="JTA">
<jta-data-source>jdbc/directory</jta-data-source>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="javax.persistence.schema- generation.database.action" value="create"/>
</properties>
</persistence-unit>
</persistence>
有谁知道如何解决这个问题?
我不记得确切的规则,但是只能保证使用该JPA注释扫描和注入特定的类集,并且该列表中不包含批处理工件。
因此,您必须执行其他类似的操作:
EntityManagerFactory emf = Persistence.createEntityManagerFactory("com.mycompany_mavenproject1_war_1.0-SNAPSHOTPU");
em = emf.createEntityManager();
或者您可以这样做:
@Named
@PersistenceContext(unitName = "com.mycompany_mavenproject1_war_1.0-SNAPSHOTPU", name = "persistence/em")
public class OrderWriter extends AbstractItemWriter {
EntityManager em;
@Override
public void open(Serializable checkpoint) {
try {
InitialContext ic = new InitialContext();
em = (EntityManager) ic.lookup("java:comp/env/persistence/em");
} catch (NamingException e) {
throw new RuntimeException(e);
}
}
@Override
public void writeItems(List<Object> list){
for (Object p : list) {
em.merge(p);
}
}
}
使用web.xml:
<persistence-context-ref>
<persistence-context-ref-name>persistence/em</persistence-context-ref-name>
<persistence-unit-name>com.mycompany_mavenproject1_war_1.0-SNAPSHOTPU</persistence-unit-name>
</persistence-context-ref>
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