prodserviceimpl.java

网上商店 新增功能： 1

package netstore.service;

import java.sql.Timestamp;
import java.util.List;
import java.util.Iterator;
import java.util.ArrayList;

import netstore.businessobjects.*;

// Import the exceptions used
import netstore.framework.exceptions.DatastoreException;

import javax.servlet.ServletContext;

// Import the implementation specific packages
//hibernate 3.0
import org.hibernate.*;

import org.apache.log4j.*;

/**
 * 业务代理实现
 * @author huangyongfeng
 *
 */
public class ProdServiceImpl extends NetstoreServiceImpl{
    private static Logger logger = Logger.getLogger(ProdServiceImpl.class.getName());	
  
 
  /**
   * Create the service *
   */
  public ProdServiceImpl() throws DatastoreException {
    super();
  }

  /**
   * Return a list of items.
   * 获取产品，从第几条开始，获取几条
   * 查询时也加入事务？
   */
  public List getItems(int beginPage,int length) throws DatastoreException {
    Session session = HibernateUtil.getSession();
    
    Transaction tx = null;
    try {
      tx = session.beginTransaction();

      String hql = "from Item i";
      //不查询出全部内容而得到记录总数
      //((Integer)session.iterate(hql).next()).intValue()
      Query query = session.createQuery("select count(*) " + hql);
      rowCount = ((Integer)query.iterate().next()).intValue();
      //rowCount = ((Integer)session.iterate("select count(*) " + hql).next()).intValue();

      logger.info("rowCount:"+rowCount);
      this.setRowCount(rowCount);      
      
      //查询所需页资料
      query = session.createQuery("from Item i order by i.basePrice asc");
      
      if(beginPage > 0)
      {
          query.setFirstResult(length * (beginPage - 1));
      }
      query.setMaxResults(length);

      List result = query.list();

      tx.commit();

      return toGBEncoding(result);
    }catch (Exception ex) {
      HibernateUtil.rollbackTransaction(tx);
      throw DatastoreException.datastoreError(ex);
    } finally {
      // No matter what, close the session
      HibernateUtil.closeSession(session);
    }
  }

  /**
   * 通过id获取产品对象
   */
  public Item getItemById( Long id)throws DatastoreException{
    Session session = HibernateUtil.getSession();
    Transaction tx = null;
    try {
      tx = session.beginTransaction();
      Item item =(Item)session.get(Item.class,id);;
      tx.commit();

      //实际此时直接返回对象也可
      return toGBEncoding(item);
    }catch (Exception ex) {
      HibernateUtil.rollbackTransaction(tx);
      throw DatastoreException.datastoreError(ex);
    } finally {
      // No matter what, close the session
      HibernateUtil.closeSession(session);
    }
  }

}