Analysis of the similarities and differences of c:foreach traversal and s:iterator traversal in JSP _jsp programming

This paper analyzes the similarities and differences of c:foreach traversal and s:iterator traversal in JSP. Share to everyone for your reference. Specifically as follows:

①jstl C:foreach

First, let's look at an ordinary 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 {//
 Plate list 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) {//number of replies list<topic> Topic = Topicdao.gettopicbyboardid (b.getb
  OrderId ());
   if (null!=topic) {int num = topic.size ();
  Count.add (num);
  else {count.add (0);
  }//recently updated Topic t = topicdao.getlasttopic (B.getborderid ());
  Lasttopic.add (t); Recently updated author 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, Ioexcepti
 On {this.doget (request, response);

 }
}

Main.jsp:

<%@ taglib uri= "Http://java.sun.com/jsp/jstl/core" prefix= "C"%> <c:if "test=}" > <c:foreach var= "B" items= "${requestscope.boards}" varstatus= "status" > <tr> <td width= "6%" height= " > </td> <td width= "67%" > <div align= "left" class= "Bluespan" >  <a href= "Logined/tolistaction?boardid=${b.borderid}" > ${b.bordername}</a> & Lt;/div> </td> <td> ${requestscope.count[status.index]} </td> <td> <p align= "left" &G
  T ${requestscope.lasttopic[status.index].title} </p> <br/> <p align= "left" > ${requestscope.user S[status.index].username} </p> <br/> <p align= "left" > Modified: <br> ${requestscope.lastt

 Opic[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 Board
 Daoimpl ();
 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 () {//Plate list 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) {//number of replies list<topic> Topic = Topicdao.gettopicbyboardid (b.getb
  OrderId ());
   if (null!= topic) {int num = topic.size (); Count.add (num);
  else {count.add (0);
  }//recently updated Topic t = topicdao.getlasttopic (B.getborderid ());
  Lasttopic.add (t);
  Recently updated author 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=", "> </td> <td width=" 67% "> <div align= "left" class= "Bluespan" >  <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"/&
  Gt
  </p> <br/> <p align= "left" > <s:property value= "#request. lasttopic[#st. Index].username"/> </p> <br/> <p align= "Left" > Modify time: <br/> <s:property value= "#request. lasttopic[#st. Dex].modifytime "/> </p> <br/> </td> </tr> </s:iterator> </s:if>

 

I hope this article will help you with your JSP programming.