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：
①jstlc:foreach
首先我们来看一个普通的servlet:
importcom.xy.entity.Board;
importcom.xy.entity.Topic;
importcom.xy.entity.User;
publicclassToMainActionextendsHttpServlet
{
privateIBoarderDaoboardDao=newBoardDaoImpl();
privateITopicDaotopicDao=newTopicDaoImpl();
privateIUserDaouserDao=newUserDaoImpl();
publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException
{
//板块列表
List<Board>boards=boardDao.getAllBoard();
List<Integer>count=newArrayList<Integer>();
List<User>users=newArrayList<User>();
List<Topic>lastTopic=newArrayList<Topic>();
if(null!=boards)
{
for(Boardb:boards)
{
//回帖数
List<Topic>topic=topicDao.getTopicByBoardId(b.getborderId());
if(null!=topic)
{
intnum=topic.size();
count.add(num);
}
else
{
count.add(0);
}
//最近更新
Topict=topicDao.getLastTopic(b.getborderId());
lastTopic.add(t);
//最近更新的作者
Useru=userDao.getUserByuId(t.getUid());
users.add(u);
}
request.setAttribute("boards",boards);
request.setAttribute("count",count);
request.setAttribute("users",users);
request.setAttribute("lastTopic",lastTopic);
RequestDispatcherdis=request.getRequestDispatcher("main.jsp");
dis.forward(request,response);
}
}
publicvoiddoPost
(HttpServletRequestrequest,HttpServletResponseresponse)throwsServletException,IOException
{
this.doGet(request,response);
}
}
main.jsp:
<%@tagliburi="http://java.sun.com/jsp/jstl/core"prefix="c"%>
<c:iftest="${requestScope.boards!=null}">
<c:forEachvar="b"items="${requestScope.boards}"varStatus="status">
<tr>
<tdwidth="6%"height="68">
</td>
<tdwidth="67%">
<divalign="left"class="blueSpan">
<imgsrc="images/topic.gif"width="18"height="21"/>
<ahref="logined/ToListAction?boardId=${b.borderId}">
${b.borderName}</a>
</div>
</td>
<td>
${requestScope.count[status.index]}
</td>
<td>
<palign="left">
${requestScope.lastTopic[status.index].title}
</p>
<br/>
<palign="left">
${requestScope.users[status.index].userName}
</p>
<br/>
<palign="left">
修改时间：
<br>
${requestScope.lastTopic[status.index].modifyTime}
</p>
<br/>
</td>
</tr>
</c:forEach>
</c:if>
②s:iterator
packagecom.xy.action;
action
publicclassToMainActionextendsActionSupportimplementsRequestAware
{
privateIBoarderDaoboardDao=newBoardDaoImpl();
privateITopicDaotopicDao=newTopicDaoImpl();
privateIUserDaouserDao=newUserDaoImpl();
privateMap<String,Object>request;
publicvoidsetBoardDao(IBoarderDaoboardDao)
{
this.boardDao=boardDao;
}
publicvoidsetTopicDao(ITopicDaotopicDao)
{
this.topicDao=topicDao;
}
publicvoidsetUserDao(IUserDaouserDao)
{
this.userDao=userDao;
}
publicStringexecute()
{
//板块列表
List<Board>boards=boardDao.getAllBoard();
List<Integer>count=newArrayList<Integer>();
List<User>users=newArrayList<User>();
List<Topic>lastTopic=newArrayList<Topic>();
if(null!=boards)
{
for(Boardb:boards)
{
//回帖数
List<Topic>topic=topicDao.getTopicByBoardId(b.getBorderId());
if(null!=topic)
{
intnum=topic.size();
count.add(num);
}else
{
count.add(0);
}
//最近更新
Topict=topicDao.getLastTopic(b.getBorderId());
lastTopic.add(t);
//最近更新的作者
Useru=userDao.getUserByuId(t.getUid());
users.add(u);
}
request.put("boards",boards);
request.put("count",count);
request.put("users",users);
request.put("lastTopic",lastTopic);
}
returnSUCCESS;
}
publicvoidsetRequest(Map<String,Object>request)
{
this.request=request;
}
}
main.jsp：
<%@tagliburi="/struts-tags"prefix="s"%> <s:iftest="#request.boards!=null"> <s:iteratorvalue="#request.boards"id="b"status="st"> <tr> <tdwidth="6%"height="68"> </td> <tdwidth="67%"> <divalign="left"class="blueSpan"> <imgsrc="images/topic.gif"width="18"height="21"/> <ahref="logined/ToListAction?boardId="+<s:propertyvalue="#b.borderId"/>+"> <s:propertyvalue="#b.borderName"/> </a> </div> </td> <td> <s:propertyvalue="#request.count[#st.index]"/> </td> <td> <br/> <palign="left"> <s:propertyvalue="#request.lastTopic[#st.index].title"/> </p> <br/> <palign="left"> <s:propertyvalue="#request.lastTopic[#st.index].userName"/> </p> <br/> <palign="left"> 修改时间： <br/> <s:propertyvalue="#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。