Configuration conf = new Configuration().configure();为什么抛出Exception in thread "main" java.lang.NoClassDefFoundError: 啊？

[cdsnmdl]

Configuration conf = new Configuration().configure();抛出异常
Exception in thread "main" java.lang.NoClassDefFoundError: org/dom4j/DocumentException

刚学hibernante eclipse建的web工程 lib目录下复制了hibernate3.jar包
hibernate.cfg.xml配置文件如下：
<?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">
<!--上面四行对所有的Hibernate连接匹配值文件都相同 -->
<!--hibernate-configuration是连接配置文件的根元素 -->
<hibernate-configuration>
<session-factory>
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connetion.url">jdbc:mysql://localhost/hibernate</property>
<property name="connection.username">root</property>
<property name="connection.password">root</property>

<!-- C3PO connection pool -->
<property name="hibernate.c3p0.max_size">20</property>
<property name="hibernate.c3p0.min_size">1</property>
<property name="hibernate.c3p0.timeout">5000</property>
<property name="hibernate.c3p0.max_statements">100</property>
<property name="hibernate.c3p0.idle_test_period">3000</property>
<property name="hibernate.c3p0.acquire_increment">2</property>
<property name="hibernate.c3p0.validate">true</property>

<!-- 指定数据库方言 -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>

<!-- 根据需要创建数据库 -->
<property name="hbm2dd1.auto">create</property>

<!-- 罗列所有的映射文件 -->
<mapping resource="News.hbm.xml"/>
</session-factory>
</hibernate-configuration>

News.hbm.xml映射文件内容：
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping
PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!--上面四行对所有的Hibernate映射文件都相同 -->
<!--hibernate-mapping是映射文件的根元素 -->
<hibernate-mapping package="tmp">
<!-- 每个CLASS元素对应一个持久化对象PO -->
<class name="News" table="news_table">
<!-- id元素定义持久化类的标示属性 -->
<id name="id" unsaved-value="null">
<generator class="identity" />
</id>
<!-- property元素定义常规属性 -->
<property name="title" />
<property name="content" />
</class>
</hibernate-mapping>

高手帮帮忙，哪里有问题呀？

[zhj92lxs]

org/dom4j/DocumentException 找不到这个类

[Landor2004]

把dom4j-x.x.x.jar加入你的工程

[a03180204]

我遇到过这种问题,不过我是环境问题,环境变量没弄好

[jumpheightway]

hibernate运行的环境没有搭建好
也就是说hibernate需要的jar没有得到供应

[BlackSky_Sun]

应该是包的问题吧。确实包（jar文件）

[my020202]

a03180204说的没错.
检查下的jdk版本，还有你的 环境变量 中的path是否设置正确了？？

[qswdcs]

我囧 package v;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.cfg.Configuration;



public class SessionManagerService {
private static SessionFactory sessionFactory=null;
// private static long timeout=0;
// private static long lastRestartTime=0;
private SessionManagerService()
{

}
private synchronized static void checkSessionFactory()
{
System.out.println("进入方法");
if(sessionFactory==null||sessionFactory.isClosed())
{
Configuration configuration=new AnnotationConfiguration().configure();
sessionFactory = configuration.buildSessionFactory();
}
else
{
try{
sessionFactory.openSession().createSQLQuery("select 1 from dual").list();
}catch(Exception e)
{
if(sessionFactory!=null&&!sessionFactory.isClosed())
sessionFactory.close();
try{
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
}catch(Exception ex)
{
throw new RuntimeException("数据库连接异常");
}
}
}
}
public synchronized static Session getSession()
{
System.out.println("调用之前");
checkSessionFactory();
return sessionFactory.openSession();
}
}
我的这个为什么不调用 啊!!!! 求高手帮忙啊