How to retrieve data from Struts 2 using OGNL

Question

I need to show registered user to users, Here am using Struts2 and I am very new it. But I know how to retrieve the elements without using Struts 2 there I will use collection set all the elements inside collection and I will put that in request scope and forwarded to the JSP page there I will use JSTL tag to retrieve all the elements but I don't know how to do it in Struts 2.

package com.uttara.reg;
import java.util.List;
import java.util.Map;
import org.apache.struts2.interceptor.SessionAware;
import com.opensymphony.xwork2.ActionSupport;
public class FetchRegisterdUserAction extends ActionSupport implements SessionAware{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private RegBean bean;
    private Map session;
    private List<RegBean> registerdUsers;
    public String execute() throws Exception {  
        System.out.println("inside execute of FA excut");
        Model m = new Model();
        registerdUsers= m.getRegisterdUsers();
        if(registerdUsers!=null){
        setRegisterdUsers(registerdUsers);
        System.out.println("inside success");
        return SUCCESS;
        }
        else{
            System.out.println("inside failure");
            return "failure";
        }
    }   
    @Override
    public void validate() {
        System.out.println("inside validate of LA");
    }
    public void setSession(Map session) {
        // TODO Auto-generated method stub

        System.out.println("inside setSession");
        this.session = session;
    }
    public List<RegBean> getRegisterdUsers() {
        return registerdUsers;
    }
    public void setRegisterdUsers(List<RegBean> registerdUsers) {
        this.registerdUsers = registerdUsers;
    }
    

}

This my JSP code where am going to retrieve individual elements but it is not working

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
 <%@ taglib uri="/struts-tags" prefix="s"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h1>Registered Users</h1>
<s:iterator value="registerdUsers">
<s:property value="#{registerdUsers.uname}"/>
</s:iterator>

What can't you do in JSTL that needs the use of Struts2 & OGNL? — Roman C, Oct 03 '13 at 07:36
i don't know where to store collection to forward to the jsp in struts 2 — user2838630, Oct 03 '13 at 07:44
Correct, the action object is on the `top` of the `valueStack`. — Roman C, Oct 03 '13 at 08:01
can plz tell me how to retrieve that set collection at the jsp side using ognl — user2838630, Oct 03 '13 at 08:15
Why are you creating a local list `List rg = m.getRegisterdUsers();` if you want to retrieve it in the page ? Just use your class level list: `registerdUsers = m.getRegisterdUsers();` — Andrea Ligios, Oct 03 '13 at 10:08
hi thanks for ur help can u plz explain me how retrive at the side of jsp using ognl iteration — user2838630, Oct 03 '13 at 11:17

score 0 · Answer 1 · answered Oct 03 '13 at 09:01

You can access the collection objects using OGNL by the index. For example you have a List collection

private List<String> myList;

public List<String> getMyList(){
  return myList;
}

public void setMyList(List<String> myList){
  this.myList = myList;
}

now in the JSP you can use an iterator s:iterator tag to traverse the collection

<s:iterator value="myList"/>
  <s:property/> 
</s:iterator>

it will write to the JSP all string values of the collection

if you want to get the individual value, you can access it by index

<s:property value="%{myList[index]}"/>

where the index is just another variable in the valueStack, you can get it from iterator, create in the context via s:set tag, or access from the action

public int getIndex(){
  return 0;
}

remember that a collection should be populated in your action before you use the iterator or access objects by index.

hi can u see my edit above i have posted the code my all retrieved elements are there rg how to set that into registerdUsers — user2838630, Oct 03 '13 at 09:21
hi thnks but that iteration is not working can u plz expline me — user2838630, Oct 03 '13 at 11:18

score 0 · Answer 2 · answered Oct 03 '13 at 13:14

Try this create getter and setter for registerdUsers;

public String execute() throws Exception {  
        System.out.println("inside execute of LA");
        Model m = new Model();
        **List<RegBean> rg = m.getRegisterdUsers();**
        if(rg!=null){
        setRegisterdUsers(rg); //set registerdUsers with rg
        session.put("user", bean.getEmail());
        return SUCCESS;
        }

In jsp

Iterate it

<s:iterator value="registerdUsers">
<s:property value="registerdUsers.uname"/>
</s:iterator>

create getter and setter method of RegisterdUsers then set rg to RegisterdUsers now iterate RegisterdUsers in your jsp — xrcwrn, Oct 03 '13 at 13:56

How to retrieve data from Struts 2 using OGNL

2 Answers2