JSP中c:foreach遍历和s:iterator遍历异同实例分析

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 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:

<%@ 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;actionpublic class ToMainAction extends ActionSupport implements RequestAware{ private IBoarderDao boardDao = new BoardDaoImpl（）; private ITopicDao topicDao = new TopicDaoImpl（）; private IUserDao userDao = new UserDaoImpl（）; private Map<String, 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 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.put（"boards", boards）;request.put（"count", count）;request.put（"users", users）;request.put（"lastTopic", lastTopic）; } return SUCCESS; } public void setRequest（Map<String, 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。