SSH框架JSP 无法显示数据库数据的问题

[shyhappyaa]

最近在学习struts+spring+hibernate，在MyEclipse中自动创建持久化类Address，在Action中用DAO调用list方法显示数据库信息，
现在可以成功调用list方法但Hibernate给我返回的username是null（MySQL中有数据），所以jsp页面中显示不出数据库信息，请问这是什么原因造成的？

这是DAO中的list方法

 public class AddressDAO extends HibernateDaoSupport implements IAddressDAO {
	public List findAllByUsername(final String username) {
		return (List) getHibernateTemplate().execute(new HibernateCallback() {
			public Object doInHibernate(Session session)
					throws HibernateException {
				List result = session.createCriteria(Address.class).add(
						Restrictions.eq("username", username)).list();
//System.out.println("111");
				return result;
			}
		});
	}
          …………

这是Action 中调用list

public class AddressAction extends DispatchAction {
	protected AddressDAO addressDAO;
	Logger log = Logger.getLogger(this.getClass());

	public AddressDAO getAddressDAO() {
		return addressDAO;
	}

	public void setAddressDAO(AddressDAO addressDAO) {
		this.addressDAO = addressDAO;
	}

	public ActionForward list(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {
		String username = (String) request.getSession().getAttribute(
				Constants.USERNAME_KEY);

		List list = addressDAO.findAllByUsername(username);

		request.setAttribute("addressList", list);

		ActionForward forward = mapping.findForward(Constants.LIST_KEY);

		return (forward);
	}

返回信息就是这样
null
Hibernate: select this_.ID as ID0_0_, this_.username as username0_0_, this_.name as name0_0_, this_.sex as sex0_0_, this_.mobile as mobile0_0_, this_.email as email0_0_, this_.qq as qq0_0_, this_.company as company0_0_, this_.address as address0_0_, this_.postcode as postcode0_0_ from address.address this_ where this_.username=?

[lvkai0452]

where this_.username=?这个条件查询没有值吧

[Study_Work_2009]

应该是username的注入问题吧

[ch370335226]

String username = (String) request.getSession().getAttribute(
Constants.USERNAME_KEY);



session 中有没有值？？？