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;
action
public 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。
【说明】：本文章由站长整理发布，文章内容不代表本站观点，如文中有侵权行为，请与本站客服联系(QQ:254677821)！