tcommentdao.java

使用JSP+Servlet+Hibernate+Struts实现的一个学生软件发布平台

package edu.neu.sspp.hibernate;

import java.util.Date;
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 TComment.
 * @see edu.neu.sspp.hibernate.TComment
 * @author MyEclipse - Hibernate Tools
 */
public class TCommentDAO extends BaseHibernateDAO {

    private static final Log log = LogFactory.getLog(TCommentDAO.class);

	//property constants
	public static final String NICK = "nick";
	public static final String IS_USER = "isUser";
	public static final String CONTENT = "content";
	public static final String USER_NAME = "userName";
	public static final String TEACHER_EMAIL = "teacherEmail";
    
    public void save(TComment transientInstance) {
        log.debug("saving TComment instance");
        try {
            getSession().save(transientInstance);
            log.debug("save successful");
        } catch (RuntimeException re) {
            log.error("save failed", re);
            throw re;
        }
    }
    
	public void delete(TComment persistentInstance) {
        log.debug("deleting TComment instance");
        try {
            getSession().delete(persistentInstance);
            log.debug("delete successful");
        } catch (RuntimeException re) {
            log.error("delete failed", re);
            throw re;
        }
    }
    
    public TComment findById( java.lang.String id) {
        log.debug("getting TComment instance with id: " + id);
        try {
            TComment instance = (TComment) getSession()
                    .get("edu.neu.sspp.hibernate.TComment", id);
            return instance;
        } catch (RuntimeException re) {
            log.error("get failed", re);
            throw re;
        }
    }
    
    public int getCount() {
    	log.debug("getting count of TComment");
    	
    	try {
        	String queryString = "select count(*) from TComment";
        	Query queryObject = getSession().createQuery(queryString);
        	
        	return ((Integer)queryObject.list().get(0)).intValue();
    	} catch (RuntimeException re) {
    		log.error("getting count of TComment failed", re);
    		throw re;
    	}
    }
    
    public List getByPage(int first, int size) {
    	log.debug("getting TComment for page");
    	
    	try {
    		//按日期降序排列
        	String queryString = "from TComment as comment order by comment.date desc";
        	Query queryObject = getSession().createQuery(queryString);
        	queryObject.setFirstResult(first);
        	//mysql似乎不支持setFetchSize，无法实现部分查询，只能通过setMaxResults在返回结果上控制
        	//queryObject.setFetchSize(size);
        	queryObject.setMaxResults(size);
        	return queryObject.list();
    	} catch(RuntimeException re) {
    		log.error("get by page failed", re);
    		throw re;
    	}
    }
    
    
    public List findByExample(TComment instance) {
        log.debug("finding TComment instance by example");
        try {
            List results = getSession()
                    .createCriteria("edu.neu.sspp.hibernate.TComment")
                    .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;
        }
    }    
    
    public List findByProperty(String propertyName, Object value) {
      log.debug("finding TComment instance with property: " + propertyName
            + ", value: " + value);
      try {
         String queryString = "from TComment 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 findByNick(Object nick) {
		return findByProperty(NICK, nick);
	}
	
	public List findByIsUser(Object isUser) {
		return findByProperty(IS_USER, isUser);
	}
	
	public List findByContent(Object content) {
		return findByProperty(CONTENT, content);
	}
	
	public List findByUserName(Object userName) {
		return findByProperty(USER_NAME, userName);
	}
	
	public List findByTeacherEmail(Object teacherEmail) {
		return findByProperty(TEACHER_EMAIL, teacherEmail);
	}
	
    public TComment merge(TComment detachedInstance) {
        log.debug("merging TComment instance");
        try {
            TComment result = (TComment) getSession()
                    .merge(detachedInstance);
            log.debug("merge successful");
            return result;
        } catch (RuntimeException re) {
            log.error("merge failed", re);
            throw re;
        }
    }

    public void attachDirty(TComment instance) {
        log.debug("attaching dirty TComment instance");
        try {
            getSession().saveOrUpdate(instance);
            log.debug("attach successful");
        } catch (RuntimeException re) {
            log.error("attach failed", re);
            throw re;
        }
    }
    
    public void attachClean(TComment instance) {
        log.debug("attaching clean TComment instance");
        try {
            getSession().lock(instance, LockMode.NONE);
            log.debug("attach successful");
        } catch (RuntimeException re) {
            log.error("attach failed", re);
            throw re;
        }
    }
}