hibernate 报错
代码如下：第63行 （LoginDAO loginDAO = new LoginDAO();）
  Login login = new Login();
login.setUsername("ad");
login.setPassword("12");
LoginDAO loginDAO = new LoginDAO();
Transaction tra = loginDAO.getSession().beginTransaction();
loginDAO.attachDirty(login);
tra.commit();
loginDAO.getSession().close();
return null;
如下报错：

type Exception report

message 

description The server encountered an internal error () that prevented it from fulfilling this request.

exception 

javax.servlet.ServletException: Servlet execution threw an exception


root cause 

java.lang.NoClassDefFoundError: org/hibernate/criterion/Criterion
com.yourcompany.struts.action.LoginAction.execute(LoginAction.java:63)
org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)


root cause 

java.lang.ClassNotFoundException: org.hibernate.criterion.Criterion
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1358)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1204)
java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
com.yourcompany.struts.action.LoginAction.execute(LoginAction.java:63)
org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)


note The full stack trace of the root cause is available in the Apache Tomcat/6.0.10 logs.


------解决方案--------------------
LoginDAO loginDAO = new LoginDAO();中的Lo