J2EE中EL和JSTL结合运用

来源：互联网发布：java cms 开源编辑：程序博客网时间：2024/06/18 14:24

这里的例子只是简单的Servlet+JSP，没有用到框架，如果用到Struts的话，只要符合Struts中Action标准，或者直接用Struts标签替代就可以了。

ToMainAction

public class ToMainAction extends HttpServlet
{
private IBoarderDao boardDao = new BoardDaoImpl();
private ITopicDao topicDao = new TopicDaoImpl();
private IUserDao userDao = new UserDaoImpl();

public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
  // 板块列表
  List<Board> boards = boardDao.getAllBoard();
  List<Integer> count = new ArrayList<Integer>();
  List<User> users = new ArrayList<User>();
  List<Topic> lastTopic = new ArrayList<Topic>();

  if (null != boards)
  {
   for (Board b : boards)
   {
    // 回帖数
    List<Topic> topic = topicDao.getTopicByBoardId(b.getBorderId());
    if (null != topic)
    {
     int num = topic.size();
     count.add(num);
    }
    else
    {
     count.add(0);
    }

    // 最近更新
    Topic t = topicDao.getLastTopic(b.getBorderId());
    lastTopic.add(t);

    // 最近更新的作者
    User u = userDao.getUserByuId(t.getUid());
    users.add(u);
   }

   request.setAttribute("boards", boards);
   request.setAttribute("count", count);
   request.setAttribute("users", users);
   request.setAttribute("lastTopic", lastTopic);

   RequestDispatcher dis = request.getRequestDispatcher("main.jsp");
   dis.forward(request, response);
  }

}

public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
this.doGet(request, response);
}

}

main.jsp

    <c:if test="${requestScope.boards!=null}">
     <c:forEach var="b" items="${requestScope.boards}"  varStatus="status">
      <tr>
       <td width="6%" height="68">
         
       </td>
       <td width="67%">
        <div align="left" class="blueSpan">
           
         <img src="images/topic.gif" width="18" height="21" />
           
         <a href="ToListAction?boardId=${b.borderId}">${b.borderName}</a>
        </div>
       </td>
       <td>
        ${requestScope.count[status.index]}
       </td>
       <td>
        <br />
        <p align="left">
         ${requestScope.lastTopic[status.index].title}
        </p>
        <br />
        <p align="left">
         ${requestScope.users[status.index].userName}
        </p>
        <br />
        <p align="left">
         修改时间：
         <br>
         ${requestScope.lastTopic[status.index].modifyTime}
        </p>
       </td>
      </tr>
     </c:forEach>
    </c:if>
   </table>

checUser.jsp

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

<c:if test="${not empty sessionScope.uinfo}">
<span style="color: blue">欢迎您：${sessionScope.uinfo.userName} </span>
<span style="color: blue"><a href="GoBackAction">退出</a> </span>
</c:if>
<c:if test="${empty sessionScope.uinfo}">
<span style=""><a href="ToLoginAction">登录</a></span>
</c:if>