forumdao.java

用java实现的一个论坛,可以供大家参考

/*******************************************************************\
*                                                                   *
*			   LightningBoard			    *
*                                                                   *
*          http://sourceforge.net/projects/lightningboard/          *
*			                                            *
*	            Copyright (c) 2002 Xiaobo Liu	            *
*                                                                   *
*********************************************************************
*                        LICENSE INFORMATION                        *
*                                                                   *
*  LightningBoard is free software; you can redistribute it and/or  *
*  modify it under the terms of the GNU General Public License as   *
*  published by the Free Software Foundation; either version 2 of   *
*  the License, or any later version.                               *
*                                                                   *
*  We don't charge anything for the use of LightningBoard, we only  *
*  require you to keep the copyright present on your site and in    *
*  the source files.                                                *
*                                                                   *
*  LightningBoard is distributed in the hope that it will be useful,*
*  but without any warranty; without even the implied warranty of   *
*  merchantability or fitness for a particular purpose. See the GNU *
*  General Public License for more details.                         *
*                                                                   *
\*******************************************************************/


package liuxiaobo.lb.dao;

import java.sql.*;
import java.util.*;
import liuxiaobo.db.*;
import liuxiaobo.lb.*;
import liuxiaobo.lb.bean.*;

public class ForumDAO  {
  private DBConnectionManager dbcm = DBConnectionManager.getInstance();

  public ForumBean execute(int f_id,int start, int range)throws ActionException{
    Connection connection=null;
    try {
      ForumBean forumBean=new ForumBean();
      connection=dbcm.getConnection();
      DBAccess dba=new DBAccess(connection);
      String sql="SELECT f_name,f_u_id,u_name,f_info,f_topics,f_messages FROM forum,user  WHERE f_u_id=u_id AND f_id=" + f_id;
      ResultSet rs=dba.openSelect(sql);
      //check result
      if (!rs.next())
        return null;
      rs.beforeFirst();

      while (rs.next()){
        forumBean.setF_id(String.valueOf(f_id));
        forumBean.setF_name(rs.getString("f_name"));
        forumBean.setF_u_id(rs.getString("f_u_id"));
        forumBean.setU_name(rs.getString("u_name"));
        forumBean.setF_info(rs.getString("f_info"));
        forumBean.setF_topics(rs.getString("f_topics"));
        forumBean.setF_messages(rs.getString("f_messages"));
      }
      rs.close();
      dba.closeSelect();
      //------------------------
      sql="SELECT t_id,t_name,t_u_id,user1.u_name as u_name,t_replies,t_views,t_lasttime,t_u_id2,user2.u_name as u_name2 FROM topic,user user1,user user2  WHERE t_u_id=user1.u_id AND t_u_id2=user2.u_id AND t_f_id=" + f_id + " ORDER BY t_lasttime DESC";
      rs = dba.openSelect(sql);
      rs.last();
      int count = rs.getRow();
      forumBean.setStart(String.valueOf(start));
      forumBean.setRange(String.valueOf(range));
      forumBean.setCount(String.valueOf(count));
      List topicList=new LinkedList();
      if (count>0){
        if(start > count){
          throw new Exception("NO_TOPICS");
        }
        rs.absolute(start);
        for(int i=0; i < range && !rs.isAfterLast();i++ ){
          Topic topic=new Topic();
          topic.setT_id(rs.getString("t_id"));
          topic.setT_name(rs.getString("t_name"));
          topic.setT_u_id(rs.getString("t_u_id"));
          topic.setU_name(rs.getString("u_name"));
          topic.setT_replies(rs.getString("t_replies"));
          topic.setT_views(rs.getString("t_views"));
          topic.setT_lasttime(rs.getString("t_lasttime"));
          topic.setT_u_id2(rs.getString("t_u_id2"));
          topic.setU_name2(rs.getString("u_name2"));
          topicList.add(topic);
          rs.next();
        }
      }
      forumBean.setTopics(topicList);
      rs.close();
      dba.closeSelect();
      //jump
      CommonDAO commonDAO=new CommonDAO();
      forumBean.setForumMap(commonDAO.getForumMap(dba));
      return forumBean;
    } catch (Exception ex) {
      throw new ActionException(ex);
    }finally{
      try {
        dbcm.freeConnection(connection);
      } catch (SQLException ex) {
        //
      }
    }
  }
}