java_web项目3

待我称王封你为后i 2021-12-20 06:47 221阅读 0赞

## java\_web项目3（文章板块内容显示） ##

文章板块内容的显示 包括图片 点赞数量（如果是该用户点赞了这篇文章样式还不一样）评论数量 还有分页展示（一页展示五篇）  
分页查询是依靠数据库做到的 如下  
pageNumber是值当前的页码  
pageSize指的是每一个所要展示的数量

String sql = "select * from (select t1.* , rownum num  from ("
    					+ "select * from campus_inform order by cDate) "
    					+ "t1 where rownum <="+pageNumber*pageSize+")"
    					+ "where num>"+(pageNumber-1)*pageSize;

根据业务需求 我创建文章类放在model下 来存放从数据库类面返回的数据

private String userId;  //用户id
        private String cId;    //文章id
        private String cName;  //文章名字
        private String cText;  //文章内容
        private Date cDate;  //发布日期
        private int cReply;  //回复数量
        private int cPrise;  //点赞数量
        private int cTransmit;//转发数量
        private int cStatus; //点赞状态  0--该用户没有给该id点赞   1--该用户给该id点赞了

首先是servle里面得到值

//查找文章
    	public void search(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		HttpSession session = request.getSession();
    		int pagenumber = 1;//设置初始页码为1
    		
    		String userId = "0";
    		User user = (User) session.getAttribute("user");
    		if(user!=null){
    			userId = user.getUserId();
    		}
    		
    		if(request.getParameter("pagenumber")!=null){
    			pagenumber =Integer.parseInt(request.getParameter("pagenumber"));
    		}
    		
    		CInfoServiceImp csi = new CInfoServiceImp();
    		List cInfoList =csi.search(pagenumber,userId);//得到文章
    		List pictureList = csi.getPicturePath();//得到所有的图片地址
    		int maxPage = csi.getMaxPage(); //得到最大页码数
    		
    		
    		request.setAttribute("pictureList", pictureList);
    		request.setAttribute("pagenumber", pagenumber);
    		request.setAttribute("maxPage", maxPage);
    		request.setAttribute("list", cInfoList);
    		request.getRequestDispatcher("campusInform.jsp").forward(request, response);
    	}

调用service进行业务处理

CInfoDaoImp cid = new CInfoDaoImp();
    		List<CInfo> cInfoList=cid.search(pageNumber,pageSize);  //得到所有的文章的内容
    		List<Prise> priseList = cid.searchPrise();   //得到所有的点赞信息
    		//判断当前用户是否给该篇文章点过赞   如果点过赞 就把点赞状态设置为1  否则设置为0
    		List<String> priseArticleId = new ArrayList<String>();
    		for(int i=0;i<priseList.size();i++){
    			if(priseList.get(i).getUserId().equals(userId)){
    				priseArticleId.add(priseList.get(i).getArticleId());
    			}
    		}
    		for(int i=0;i<priseArticleId.size();i++){
    			for(int j=0;j<cInfoList.size();j++){
    				if(priseArticleId.get(i).equals(cInfoList.get(j).getcId())){
    					cInfoList.get(j).setcStatus(1);
    				}else{
    					if(cInfoList.get(j).getcStatus()!=1){
    						cInfoList.get(j).setcStatus(0);
    					}
    				}
    			}
    		}
    		return cInfoList;

最后数据查询

public List search(int pageNumber ,int pageSize) {
    		List<CInfo> cInfoList = new ArrayList();
    		try {
    			//JDBC数据库连接 1.加载驱动
    			Class.forName("oracle.jdbc.driver.OracleDriver");
    			//2.创建链接
    			Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl", "scott", "ADMIN");
    			//3.获取一个Preparestatement
    			String sql = "select * from (select t1.* , rownum num  from ("
    					+ "select * from campus_inform order by cDate) "
    					+ "t1 where rownum <="+pageNumber*pageSize+")"
    					+ "where num>"+(pageNumber-1)*pageSize;
    			PreparedStatement psmt = conn.prepareStatement(sql);
    			
    			ResultSet rs = psmt.executeQuery();
    			while(rs.next()){
    				CInfo cInfo = new CInfo();
    				
    				String userId=rs.getString(1);
    				String cId=rs.getString(2);
    				String cName=rs.getString(3);
    				String cText=rs.getString(4);
    				Date cDate = rs.getDate(5);
    				int cReply=rs.getInt(6);
    				int cPrise=rs.getInt(7);
    				int cTransmit=rs.getInt(8);
    				
    				cInfo.setUserId(userId);
    				cInfo.setcId(cId);
    				cInfo.setcName(cName);
    				cInfo.setcText(cText);
    				cInfo.setcDate(cDate);
    				cInfo.setcReply(cReply);
    				cInfo.setcPrise(cPrise);
    				cInfo.setcTransmit(cTransmit);
    				
    				cInfoList.add(cInfo);
    			}
    			
    			if(conn!=null){
    				conn.close();
    			}
    			if(psmt!=null){
    				psmt.close();
    			}
    			return cInfoList;
    		} catch (ClassNotFoundException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		return null;
    	}

然后把结果返回servlet进行跳转到展示页面  
前端拿到代码后用el表达式得到值进行展示  
这里面还有好多细节不变一一细说 代码实现的过程中碰到的一些难题jquery的控制等等  
如果你有兴趣的话，欢迎私信我