iCoding项目----题解页面实现

iCoding项目----题解页面实现

题解页面实现

1. 题解动态展示和翻页
   ①思路跟题库差不多
   ②不同的地方是，点击超链接到题解详细页面的时候返回三个PageList，目的是方便在题解详细页面翻页。Servlet代码为

if("answer".equals(type))
		{
			List<Code> codes = new ArrayList<Code>();
			String uidStr = request.getParameter("uid");
			code.setUid(Integer.valueOf(uidStr));
			
			GetQuestionByidService gs = new GetQuestionByidServiceImpl();
			codes = gs.getQuestionByidAnsService(code);					
			
			request.setAttribute("qid", codes.get(1).getQid());
			request.setAttribute("tit", codes.get(1).getQuestionTitle());
			request.setAttribute("des", codes.get(1).getQuestionDescription());
			request.setAttribute("code", codes.get(1).getCode());
			request.setAttribute("author",codes.get(1).getUsername());
			request.setAttribute("pertit", codes.get(0).getQuestionTitle());
			request.setAttribute("perqid", codes.get(0).getQid());
			request.setAttribute("peruid", codes.get(0).getUid());
			request.setAttribute("nexttit", codes.get(2).getQuestionTitle());
			request.setAttribute("nextqid", codes.get(2).getQid());
			request.setAttribute("nextuid", codes.get(2).getUid());
			request.getRequestDispatcher("questionAns.jsp").forward(request, response);
		}

③Dao层代码为

	@Override
	public List<Code> getQuestionByidAnsDao(Code code) {
		Connection conn = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		List<Code> Codes = new ArrayList();
		try {
			
			conn = JDBCUtil.getConnection();
			String sql = "select questionDescription from questionbank where qid = ?";
			ps = conn.prepareStatement(sql);
			ps.setInt(1,code.getQid());
			rs = ps.executeQuery();
			rs.next();
			code.setQuestionDescription(rs.getString(1));
			
			sql = "select * from codes where qid = ? and uid = ?";
			ps = conn.prepareStatement(sql);
			ps.setInt(1,code.getQid());
			ps.setInt(2, code.getUid());
			rs = ps.executeQuery();
			rs.next();
			code.setQuestionTitle(rs.getString(2));
			code.setCode(rs.getString(3));
			
			
			sql = "select *from codes inner join user on  codes.uid = `user`.id and codes.uid = ?";
			ps = conn.prepareStatement(sql);
			ps.setInt(1,code.getUid());
			rs = ps.executeQuery();
			rs.next();
			code.setUsername(rs.getString(7));
			
			//changeAnsPage所需
			sql = "select * from codes inner join user on codes.uid = `user`.id";
			ps = conn.prepareStatement(sql);
			rs = ps.executeQuery();
			
			Code preCode = new Code();
			Code nextCode = new Code();
			Code tempCode = new Code();
			int count=0;
			boolean flag = false;
			while(rs.next())
			{
				count++;
				if(code.getQid()==rs.getInt(1)&&code.getUid()==rs.getInt(5))
				{
					System.out.println(code.getQid());
					System.out.println(code.getUid());
					preCode = tempCode;
					if(rs.next())
					{
						nextCode.setQid(rs.getInt(1));
						nextCode.setQuestionTitle(rs.getString(2));
						nextCode.setCode(rs.getString(3));
						nextCode.setUid(rs.getInt(5));
						nextCode.setUsername(rs.getString(7));
					}
					else
					{
						flag=true;
					}
					break;
				}
				
				tempCode.setQid(rs.getInt(1));
				tempCode.setQuestionTitle(rs.getString(2));
				tempCode.setCode(rs.getString(3));
				tempCode.setUid(rs.getInt(5));
				tempCode.setUsername(rs.getString(7));
			}
			if(count==1)
			{
				preCode.setQid(0);
			}
			if(flag)
			{
				nextCode.setQid(0);
			}
			Codes.add(preCode);
			Codes.add(code);
			Codes.add(nextCode);
			
			
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		}finally {
			try {
				JDBCUtil.closeConnection(rs, ps, conn);
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}

		return Codes;
	}

④翻页html代码为

							<div>
								<c:if test="${perqid!=0}">
								<a href="getquestionByid?type=answer&qid=${perqid}&uid=${peruid}">
									上一篇：${pertit}
								a>
								c:if>
								<c:if test="${perqid==0 }">
								<a href="#">
									当前为第一篇
								a>
								c:if>
								<br><br>
								<c:if test="${nextqid!=0 }">
								<a href="getquestionByid?&type=answer&qid=${nextqid}&uid=${nextuid}">
									下一篇：${nexttit}
								a>
								c:if>
								<c:if test="${nextqid==0}">
								<a href="#">
									当前为最后一篇
								a>
								c:if>
								
								
							div>