0
我想一個Java servlet通過Hibernate來訪問數據庫中的doGet方法和我創建HibernateUtil類調用buildSessionFactory在靜態情況下如何在調用servlet之前讓HibernateUtil靜態初始化？
測試時，我得到一個錯誤「雄貓啓動失敗」，顯然（ ？），因爲doGet方法中的openSession在HibernateUtil類中的buildSessionFactory調用之前被調用。
如何確保HibernateUtil類在Servlet中的doGet方法之前獲得靜態初始化？
這裏是類：
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtil {
private static final SessionFactory sessionFactory = buildSessionFactory();
private static SessionFactory buildSessionFactory() {
try {
// Create the SessionFactory from hibernate.cfg.xml
return new Configuration()
.configure()
.buildSessionFactory();
} catch (Throwable ex) {
System.err.println("Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError(ex);
}
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
}
我是從這樣的doGet（）方法調用：
Session session = null;
try {
session = HibernateUtil.getSessionFactory().openSession();
// ...
}
堆棧跟蹤如下：
INFO: Starting service Catalina
Feb 10, 2014 12:58:21 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.42
Feb 10, 2014 12:58:21 PM org.apache.catalina.core.ContainerBase startInternal
SEVERE: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/dbwebtest]]
at java.util.concurrent.FutureTask$Sync.innerGet(Unknown Source)
at java.util.concurrent.FutureTask.get(Unknown Source)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:800)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/dbwebtest]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
... 7 more
Caused by: java.lang.NoClassDefFoundError: org/hibernate/HibernateException
at java.lang.Class.getDeclaredFields0(Native Method)
at java.lang.Class.privateGetDeclaredFields(Unknown Source)
at java.lang.Class.getDeclaredFields(Unknown Source)
at org.apache.catalina.util.Introspection.getDeclaredFields(Introspection.java:106)
at org.apache.catalina.startup.WebAnnotationSet.loadFieldsAnnotation(WebAnnotationSet.java:263)
at org.apache.catalina.startup.WebAnnotationSet.loadApplicationServletAnnotations(WebAnnotationSet.java:142)
at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:67)
at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:405)
at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:881)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:376)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5322)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 7 more
Caused by: java.lang.ClassNotFoundException: org.hibernate.HibernateException
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
... 21 more
您對錯誤的解釋不正確。向我們展示異常的完整堆棧跟蹤。 –
它看起來像hibernate jar文件（或其依賴關係之一）不在webapp的類路徑中，即在WEB-INF/lib中：'java.lang.NoClassDefFoundError：org/hibernate/HibernateException' –
確實如此;如果您將此作爲答案提交，我可以接受。 – draca