java - Glassfish 仅限于使用 JPA/EJB/Web 服务的两个同时线程

Question

我正在通过 Web 服务公开以下 EJB3 无状态 session bean。

@Stateless
public class UserRoleFacade implements UserRoleFacadeLocal {
    @PersistenceContext(unitName = "SimpleEA-ejbPU")
    private EntityManager em;

    public int count() {
        System.out.println("thisClass=" + this.getClass().getSimpleName() + "@" + this.hashCode() + ", em=" + em);
        try {
            Thread.sleep(10000); // 10 sec
        } catch (InterruptedException ex) {
            Logger.getLogger(UserFacade.class.getName()).log(Level.SEVERE, null, ex);
        }
        return 0;
    }

}

如您所见，它并没有做太多事情——事实上它除了在收到请求后 hibernate 10 秒外什么也没做。我创建此代码作为实验，以了解有关 EntityManager 如何在多线程环境中工作的更多信息。

Web 服务如下所示:

@WebService(serviceName="UserRole")
public class UserRoleWebService {
    @EJB
    private UserRoleFacadeLocal ejbRef;// Add business logic below. (Right-click in editor and choose
    // "Insert Code > Add Web Service Operation")

    @WebMethod(operationName = "count")
    public int count() {
        return ejbRef.count();
    }

}

为了进行测试，我启动了 5 个浏览器，指向 Web 服务测试器，然后将它们全部启动。这是打印出来的结果:

INFO: thisClass=UserRoleFacade@11511572, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@23961
INFO: thisClass=UserRoleFacade@32513964, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@1af5c5a
INFO: thisClass=UserRoleFacade@11511572, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@23961
INFO: thisClass=UserRoleFacade@32513964, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@1af5c5a
INFO: thisClass=UserRoleFacade@11511572, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@23961

<罢工>

为了进行测试，我采纳了 Bozho 的建议并使用 15 个线程设置 JMeter。这是打印出来的结果:

INFO: thisClass=UserRoleFacade@3869465, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@55a5d0, thread=Thread[http-thread-pool-17025-(2),10,Grizzly]
INFO: thisClass=UserRoleFacade@5558947, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@d0e940, thread=Thread[http-thread-pool-17025-(1),10,Grizzly]
INFO: thisClass=UserRoleFacade@20208512, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@635f47, thread=Thread[http-thread-pool-17025-(39),10,Grizzly]
INFO: thisClass=UserRoleFacade@23924919, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@16478c1, thread=Thread[http-thread-pool-17025-(41),10,Grizzly]
INFO: thisClass=UserRoleFacade@6172173, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@121691b, thread=Thread[http-thread-pool-17025-(40),10,Grizzly]
INFO: thisClass=UserRoleFacade@3869465, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@55a5d0, thread=Thread[http-thread-pool-17025-(2),10,Grizzly]
INFO: thisClass=UserRoleFacade@5558947, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@d0e940, thread=Thread[http-thread-pool-17025-(1),10,Grizzly]
INFO: thisClass=UserRoleFacade@23924919, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@16478c1, thread=Thread[http-thread-pool-17025-(39),10,Grizzly]
INFO: thisClass=UserRoleFacade@20208512, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@635f47, thread=Thread[http-thread-pool-17025-(40),10,Grizzly]
INFO: thisClass=UserRoleFacade@6172173, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@121691b, thread=Thread[http-thread-pool-17025-(41),10,Grizzly]
INFO: thisClass=UserRoleFacade@3869465, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@55a5d0, thread=Thread[http-thread-pool-17025-(2),10,Grizzly]
INFO: thisClass=UserRoleFacade@5558947, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@d0e940, thread=Thread[http-thread-pool-17025-(1),10,Grizzly]
INFO: thisClass=UserRoleFacade@23924919, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@16478c1, thread=Thread[http-thread-pool-17025-(39),10,Grizzly]
INFO: thisClass=UserRoleFacade@6172173, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@121691b, thread=Thread[http-thread-pool-17025-(41),10,Grizzly]
INFO: thisClass=UserRoleFacade@20208512, em=com.sun.enterprise.container.common.impl.EntityManagerWrapper@635f47, thread=Thread[http-thread-pool-17025-(40),10,Grizzly]

如您所见， (以及我从浏览器中看到的)是只有 2 只有 5 个线程同时运行。 EJB 和 EntityManager 的实例看起来都可能在某处受到限制。那是哪里？

在 Glassfish 应用服务器上，我的设置看起来是:

• 连接池:8个初始连接，最多32个
• ejb 容器:初始 0 个，最大 32 个

我猜这些没问题。 EnitiyManager 在某处有设置吗？我还应该看什么？

Answer 1

在管理控制台中检查 configuration>thread-pools>thread-pool#min-thread-pool-size(应该是 2)。但这只是一分钟，当然不是最大值。