Question

有些奇怪的事发生在我身上。我有一个项目，我正在测试我的数据访问层，好吗？但我跑了测试，他已经过去了。后来我发现我的Mysql Diamond没有运行。可能会发生什么？

//测试代码

public class AppTest {

static final Logger log = Logger.getLogger(AppTest.class);

@Test
public void sessionTest() { // Passed
    Session s = HibernateUtil.getSessionFactory().openSession();
    Assert.assertTrue(s.isOpen());
}

@Test
public void fetchEvent() { // Failed
    EventDao edao = new EventDao();
    Event e = null;
    try {
        e = edao.find(1);
    } catch (Exception ex) {
        log.fatal(ex.getMessage());
    }
    Assert.assertNotNull(e);
}

@Test
public void fetchAll() { // Failed
    EventDao edao = new EventDao();
    List<Event> e = null;
    try {
        e = edao.all(); // I have 6 rows on the Event table
    } catch (Exception ex) {
        log.fatal(ex.getMessage());
    }
    Assert.assertEquals(e.size(), 6);
}

}

// HibernateUtil

public class HibernateUtil {

private static final SessionFactory sessionFactory;

static {
    try {
        // Create the SessionFactory from standard (hibernate.cfg.xml) 
        // config file.
        sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
    } catch (Throwable ex) {
        // Log the exception. 
        System.err.println("Initial SessionFactory creation failed." + ex);
        throw new ExceptionInInitializerError(ex);
    }
}

public static SessionFactory getSessionFactory() {
    return sessionFactory;
}

}

// src / main / resources / hibernate.cfg.xml代码

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
    <!-- Connection settings -->
    <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/MyDB</property>
    <property name="hibernate.connection.username">root</property>

    <!-- Class mappings -->
    ...
    <mapping class="br.siseventos.siseventosmaventest.model.Event"/>
    ...
</session-factory>

// EventDao Code

public class EventDao extends BaseDao<Event> {

}

// BaseDao Code

public abstract class BaseDao<T> implements Dao<T> {
// Fields

private Class actualClass;

// Constructor
public BaseDao() {

    // Fetching generic class parameter
    actualClass = (Class) ((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[0];
}

// Getters e Setters
public Class getActualClass() {
    return actualClass;
}

public void setActualClass(Class actualClass) {
    this.actualClass = actualClass;
}

// Service
public T find(int id) throws Exception {
    Session session = HibernateUtil.getSessionFactory().openSession();
    Transaction t = null;
    T o = null;
    try {
        t = session.beginTransaction();
        o = (T) session.get(actualClass, new Integer(id));
        t.commit();
    } catch (Exception e) {
        if (t != null) {
            try {
                t.rollback();
            } catch (Exception ex) {
            }
        }
        throw e;
    } finally {
        if (session != null) {
            session.close();
        }
    }
    return o;
}

public List<T> all() throws Exception {
    Session session = HibernateUtil.getSessionFactory().openSession();
    Transaction t = null;
    List<T> o = null;
    try {
        t = session.beginTransaction();
        o = (List<T>) session.createQuery("from " + getActualClassName()).list();
        t.commit();
    } catch (Exception e) {
        if (t != null) {
            try {
                t.rollback();
            } catch (Exception ex) {
            }
        }
        throw e;
    } finally {
        if (session != null) {
            session.close();
        }
    }

    return o;
}

// Util
public String getActualClassName() {
    return getActualClass().getSimpleName();
}

}

Answer 1

AFAIK开启会话并不意味着打开连接。它在第一次使用时打开

即使mysqld没有启动，Session似乎也存在

1 个答案: