getsession为null问题

[simonhchen]

Customer cust=(Customer) request.getSession().getAttribute("recust");
cardao = new GoodsDaoImpl();
List<Message> list = cardao.findMessageByCustID(4);

方法：public List<Message> findMessageByCustID(int custid) {
String sql = "SELECT g.gname,c.custname,m.mdes from message as m,customer as c,goods AS g where c.id = g.custid and m.gid = g.gid AND m.custid = "+custid;
SQLQuery sqlQuery = this.getSession().createSQLQuery(sql);
sqlQuery.addScalar("gname",Hibernate.STRING).addScalar("custname",Hibernate.STRING).addScalar("mdes",Hibernate.STRING);
sqlQuery.setResultTransformer(Transformers.aliasToBean(Message.class));
List<Message> list = sqlQuery.list();
return list;
}

错误提示：java.lang.NullPointerException
at org.springframework.orm.hibernate3.support.HibernateDaoSupport.getSession(HibernateDaoSupport.java:140)
at com.myproject.carssale.dao.impl.GoodsDaoImpl.findMessageByCustID(GoodsDaoImpl.java:69)
我在单独一个页面中调用这个方法时候是能行的。现在在action中调用这个方法时提示上述错误