本文实例分析了JSP中c:foreach遍历和s:iterator遍历的异同。分享给大家供大家参考。具体如下：
①jstl c:foreach
首先我们来看一个普通的servlet:
import com.xy.entity.Board;
import com.xy.entity.Topic;
import com.xy.entity.User;
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
ListBoard> boards = boardDao.getAllBoard();
ListInteger> count = new ArrayListInteger>();
ListUser> users = new ArrayListUser>();
ListTopic> lastTopic = new ArrayListTopic>();
if (null != boards)
{
for (Board b : boards)
{
// 回帖数
ListTopic> 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:
%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
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="logined/ToListAction?boardId=${b.borderId}">
${b.borderName}/a>
/div>
/td>
td>
${requestScope.count[status.index]}
/td>
td>
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>
br />
/td>
/tr>
/c:forEach>
/c:if>
②s:iterator
package com.xy.action;
action
public class ToMainAction extends ActionSupport implements RequestAware
{
private IBoarderDao boardDao = new BoardDaoImpl();
private ITopicDao topicDao = new TopicDaoImpl();
private IUserDao userDao = new UserDaoImpl();
private MapString, Object> request;
public void setBoardDao(IBoarderDao boardDao)
{
this.boardDao = boardDao;
}
public void setTopicDao(ITopicDao topicDao)
{
this.topicDao = topicDao;
}
public void setUserDao(IUserDao userDao)
{
this.userDao = userDao;
}
public String execute()
{
// 板块列表
ListBoard> boards = boardDao.getAllBoard();
ListInteger> count = new ArrayListInteger>();
ListUser> users = new ArrayListUser>();
ListTopic> lastTopic = new ArrayListTopic>();
if (null != boards)
{
for (Board b : boards)
{
// 回帖数
ListTopic> 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.put("boards", boards);
request.put("count", count);
request.put("users", users);
request.put("lastTopic", lastTopic);
}
return SUCCESS;
}
public void setRequest(MapString, Object> request)
{
this.request = request;
}
}
main.jsp：
%@ taglib uri="/struts-tags" prefix="s"%>
s:if test="#request.boards!=null">
s:iterator value="#request.boards" id="b" status="st">
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="logined/ToListAction?boardId="+s:property value="#b.borderId"/>+">
s:property value="#b.borderName" />
/a>
/div>
/td>
td>
s:property value=" #request.count[#st.index]" />
/td>
td>
br />
p align="left">
s:property value="#request.lastTopic[#st.index].title" />
/p>
br />
p align="left">
s:property value=" #request.lastTopic[#st.index].userName" />
/p>
br />
p align="left">
修改时间：
br/>
s:property value=" #request.lastTopic[#st.index].modifyTime" />
/p>
br />
/td>
/tr>
/s:iterator>
/s:if>
希望本文所述对大家的JSP程序设计有所帮助。
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