JSP中c:foreach遍历和s:iterator遍历异同实例分析
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2023-01-29 10:32:13
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s...
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。
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