学dwr时候写的一个简单的聊天室

package com.liujun.hibernate; import java.util.List; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.hibernate.LockMode; import org.hibernate.Query; import org.hibernate.criterion.Example; /** * Data access object (DAO) for domain model class User. * @see com.liujun.hibernate.User * @author MyEclipse - Hibernate Tools */ public class UserDAO extends BaseHibernateDAO { private static final Log log = LogFactory.getLog(UserDAO.class); //property constants public static final String USERNAME = "username"; public static final String PASSWORD = "password"; public void save(User transientInstance) { log.debug("saving User instance"); try { getSession().save(transientInstance); getSession().beginTransaction().commit(); log.debug("save successful"); } catch (RuntimeException re) { log.error("save failed", re); throw re; } } public void delete(User persistentInstance) { log.debug("deleting User instance"); try { getSession().delete(persistentInstance); log.debug("delete successful"); } catch (RuntimeException re) { log.error("delete failed", re); throw re; } } public User findById( java.lang.Integer id) { log.debug("getting User instance with id: " + id); try { User instance = (User) getSession() .get("com.liujun.hibernate.User", id); return instance; } catch (RuntimeException re) { log.error("get failed", re); throw re; } } public List findByExample(User instance) { log.debug("finding User instance by example"); try { List results = getSession() .createCriteria("com.liujun.hibernate.User") .add(Example.create(instance)) .list(); log.debug("find by example successful, result size: " + results.size()); return results; } catch (RuntimeException re) { log.error("find by example failed", re); throw re; } } @SuppressWarnings("unchecked") public List<User> findByProperty(String propertyName, Object value) { log.debug("finding User instance with property: " + propertyName + ", value: " + value); try { String queryString = "from User as model where model." + propertyName + "= ?"; Query queryObject = getSession().createQuery(queryString); queryObject.setParameter(0, value); return queryObject.list(); } catch (RuntimeException re) { log.error("find by property name failed", re); throw re; } } public List findByUsername(Object username) { return findByProperty(USERNAME, username); } public List findByPassword(Object password) { return findByProperty(PASSWORD, password); } public User merge(User detachedInstance) { log.debug("merging User instance"); try { User result = (User) getSession() .merge(detachedInstance); log.debug("merge successful"); return result; } catch (RuntimeException re) { log.error("merge failed", re); throw re; } } public void attachDirty(User instance) { log.debug("attaching dirty User instance"); try { getSession().saveOrUpdate(instance); log.debug("attach successful"); } catch (RuntimeException re) { log.error("attach failed", re); throw re; } } public void attachClean(User instance) { log.debug("attaching clean User instance"); try { getSession().lock(instance, LockMode.NONE); log.debug("attach successful"); } catch (RuntimeException re) { log.error("attach failed", re); throw re; } } }