【发布时间】：2017-01-20 18:19:18
【问题描述】：
我正在使用 EJB 计时器，但在同一项目中尝试同时运行计时器和持久实体时遇到了麻烦。在我的初始设置中，我只有计时器，它们按预期触发：
@Stateless
public class TimerHandler {
@Resource
protected TimerService mTimerService;
@PostConstruct
public void init() {
// could do cool stuff but choose not to
}
public Timer start(long aDuration) {
TimerConfig conf = new TimerConfig();
conf.setPersistent(false); // don't want the timer to be saved
return mTimerService.createSingleActionTimer(aDuration, conf);
}
@Timeout
public void timeOutAction(Timer aTimer) {
// does fancy stuff
System.out.println("So fancy :)");
}
}
我在让计时器运行时遇到了一些麻烦，但我采取了蛮力的方式并重新安装了 Payara (Glassfish)。在此之后使用计时器很好。我可以这样开始和取消它：
@Stateful
public class MyClass {
@EJB
private TimerHandler mTimerHandler;
private Timer mTimer;
public void startTimer(int aDuration) {
mTimer = mTimerHandler.start(aDuration);
}
public void stopTimer() {
try {
mTimer.cancel();
} catch (NoSuchObjectLocalException | NullPointerException ex) {
System.out.println("There is no timer running.");
}
}
}
但是，在我尝试将实体添加到我的项目后，问题就出现了。我的实体如下所示：
@Entity
public class TestEntity implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String testValue;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getTestValue() {
return testValue;
}
public void setTestValue(String value) {
testValue = value;
}
// removed standard code for @Override of equals(),
// hashCode() & toString()
}
我通过我的控制器 bean 进行操作：
@Stateless
public class TestDBController {
@PersistenceContext(unitName = "TimerTestWithDBPU")
private EntityManager em;
public long saveValue(String value) {
TestEntity entity = new TestEntity();
entity.setTestValue(value);
em.persist(entity);
em.flush();
return entity.getId();
}
public String getValue(long aId) {
TestEntity entity = em.find(TestEntity.class, aId);
return entity.getTestValue();
}
}
我的 Persistence Unit (persistence.xml) 按以下方式设置：
<?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="TimerTestWithDBPU" transaction-type="JTA">
<jta-data-source>jdbc/timer_test_pool</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>
添加此实体和持久性单元后，我收到以下错误：
EJB Timer Service is not available.
Timers for application with id [XYZ] will not be deleted
这是为什么？不能同时使用 ejb 计时器和持久实体运行应用程序吗？
【问题讨论】：
标签： jpa jakarta-ee timer payara