Session in jsp

[Mahesh Lohi]

Hi all,

I wish to know how to put session. In a way once a user logs in the session must end only when the user logs out. Like the one used in this forum once I log in all my posts are visible but when loged out non of them are visible.

Thank you in advanece

[Bear Bibeault]

Firstly, not really the type of thing to be doing from a JSP. Maintaining state and other types of processing is best done in servlet controllers.

That said, using the session is easy. You can obtain the session from the request instance passed to a servlet and use the setAttribute() and getAttribute() methods to create and fetch scoped variables.

To track logins, place a scoped variable in the session when a user successfully logs in, and remove it when he or she logs out. The presence of the scoped variable indicates that the user is logged in.

If the session times out, the scoped variable is automatically removed even if the user doesn't remember to log out.

[chaitanya karthikk]

In servlet Controller use

HttpSession session=request.getSession();

.
This will create a session for you. If the session already exists then it will be assigned to session object here. Otherwise the controller will create one for you. You need not check whether the session exists or not. Every thing is handled by the container itself.

Once you logout you can use

session.invalidate();

Otherwise you can mention the session time out using

session.setMaxInactiveInterval(int):

.
Here you have to mention it in form of seconds. i.e. for 1 hour you have to mention it as 60*60. For each and every session you create you can specify the time.
If you don't want to mention it each and every time, you can set it in the application level in the deployment descriptor.

<session-config>
  	<session-timeout>60</session-timeout>
</session-config>

In the deployment descriptor you mention the time in minutes. Here 60 means 60 minutes.

Hope this may help you. Have a nice day.

[Mahesh Lohi]

Thank you for the quick response.

In my case I have 1st jsp onsubmit of which it will takes to the 2nd jsp, on submit of the 2nd jsp, I am redirecting it to the 2nd jsp again. The session value passed in the 1st jsp must be valid till I close the browser. Is it posible. Am new to java . Please help.


Thank you in advance.

[chaitanya karthikk]

Mahi Lohi wrote:Thank you for the quick response.

In my case I have 1st jsp onsubmit of which it will takes to the 2nd jsp, on submit of the 2nd jsp, I am redirecting it to the 2nd jsp again. The session value passed in the 1st jsp must be valid till I close the browser. Is it posible. Am new to java . Please help.


Thank you in advance.

Hi Mahi, can you explain it clearly

[Mahesh Lohi]

Am accepting user in put in say A.jsp and in Action class am inserting the user's input into the DB and passing the one of the user input in session to B.jsp.

In B.jsp user has to fill some fields and select yes or no to continue. If the user selects yes then in B.jsp's action class am inserting some values to the DB and redirecting it to B.jsp.

Now the session value passed to B.jsp at the first by A.jsp must be carried again.

Hope am clear

Thank you in advance

[chaitanya karthikk]

Mahi, one thing you must remember, a session once created will have a time out, it depends on the programmer, if the programmer doesn't specify the session time out then the container will take care of it.
Not all the containers will take care about session time out, a few will do for the programmers, for example tomcat will invalidate the sessions after 30 minutes default. If you want to handle it you ca. If you want the session not to time out use

session.maxInactiveInterval(-1)

. It means session will never expire.

Normally people won't do this. You said that the session must never expire until the browser window is open. We cannot know how much time a user will keep his browser open. Each user has is own way.

The session expires only if the user is idle for 30 minutes or the specified time. Take a scenario, you have specified that the session time out is 60 minutes, a user is idle for 59 minutes, then the user has clicked some link, now after 1 minute the session wont expire, again its life is extended to 60 minutes. If the user performs an action after 60 minutes, since the session is expired the user can't see any result.

[Mahesh Lohi]

Do see my post above your

Hope you dont mind

[chaitanya karthikk]

You need not bother about the session, you can again use it in B.jsp even though you did not forward the session from B.jsp to B.jsp.
The session is present at the application level until the session time outs.

[Mahesh Lohi]

geting error of the kind "java.lang.NumberFormatException: For input string: "ordr (value_in_session)"

[chaitanya karthikk]

Mahi Lohi wrote:geting error of the kind "java.lang.NumberFormatException: For input string: "value_in_session"

Please paste your code.

[Mahesh Lohi]

    <html:form action="ordertake" method="post">
   OutLet : <input type="text" name="outlet" id="outlet">
   Sales Man : <input type="text" name="salename" id="salename">
   <input type="submit" value="next">
 </html:form>

Action Class

public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
String out_name=request.getParameter("outlet");
String salemane=request.getParameter("salename");
SimpleDateFormat sdfDate = new SimpleDateFormat("dd/MM/yyyy");
Date now = new Date();
String strDate = sdfDate.format(now);
Class.forName("com.mysql.jdbc.Driver");
String url=("jdbc:mysql://localhost:3306/warehouse?"+"user=root&password=123456");
Connection con=DriverManager.getConnection(url);
ResultSet rst=null;
PreparedStatement stm = con.prepareStatement("insert into order_intake (outlet_name,sales_man,order_date) values(?,?,?)");
stm.setString(1, out_name);
stm.setString(2, salemane);
stm.setString(3, strDate);
stm.executeUpdate();
ResultSet rs=null;
PreparedStatement stmtk = con.prepareStatement("update orde set ord_no=ord_no+1");
stmtk.executeUpdate();

       PreparedStatement stmt = con.prepareStatement("select * from orde ");
        rs=stmt.executeQuery();
        while(rs.next()){
        int kk=rs.getInt("ord_no");
         HttpSession sess=request.getSession(true);
        sess.setAttribute("order",kk);
        }

return mapping.findForward(SUCCESS);

}
}

Success forward will direct to

% int ordr=(Integer) session.getAttribute("order");%>
        <html:form action="geninvoice" method="post">><table >
             order # is : <input type="hidden" size="4" name="order_no" id="order_no" value="ordr"><br><br>
             Item Name :<input type="text" name="item_name" id="item_name"><br><br>
             Weight in kgs : <input type="text" size="4" name="wt" id="wt"><br><br>
             UOM : <input type="text" name="uom" size="6" id="uom"><br><br>
             MRP : <input type="text" size="6" name="mrp" id="mrp"><br>    <br>
             Selling Price : <input type="text" size="6" name="sp" id="sp"><br> <br>   
             Qty/Pck : <input type="text" size="6" name="qtypck" id="qtypck"><br>  <br>  
             Free : <input type="text" name="free" size="3" id="free"><br><br>
             Discount % : <input type="text" name="discper" size="3" id="discper"><br><br>
             Vat % : <input type="text" name="vat" size="3" id="vat"><br><br>
             Sales Man :<input type="text" name="sal_man" size="3" id="sal_man"><br><br>
             Continue:<select id="sele" name="sele">
             <option value="yes">Yes</option>
             <option value="no">No</option><br>
            
             </select>
             <input type="submit" ></table>
        </html:form>

Action class for the above JSP


/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

package com.myapp.struts;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.sql.*;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionForward;
import javax.servlet.http.HttpSession;
/**
*
* @author Mahi
*/

   
public class InvoiceStrutsAction extends org.apache.struts.action.Action {
    
    /* forward name="success" path="" */
    private final static String SUCC = "succ";
     private final static String CONTI ="conti" ;
    /**
     * This is the action called from the Struts framework.
     * @param mapping The ActionMapping used to select this instance.
     * @param form The optional ActionForm bean for this request.
     * @param request The HTTP Request we are processing.
     * @param response The HTTP Response we are processing.
     * @throws java.lang.Exception
     * @return order_no,item_name,wt,uom,mrp,qtypck,free,grsamt,discper
     */ 
    public ActionForward execute(ActionMapping mapping, ActionForm  form,
            HttpServletRequest request, HttpServletResponse response)
            throws Exception {
        String or_no=request.getParameter("order_no");
        String it_nam=request.getParameter("item_name");
        String wth=request.getParameter("wt");
        String um=request.getParameter("uom");
        String mr=request.getParameter("mrp");
        String slp=request.getParameter("sp");
        String qty=request.getParameter("qtypck");
        String fre=request.getParameter("free");
        String disp=request.getParameter("discper");
        String vt=request.getParameter("vat");
        String sman=request.getParameter("sal_man");
        String sel=request.getParameter("sele");
        //date
        SimpleDateFormat sdfDate = new SimpleDateFormat("dd/MM/yyyy");
        Date now = new Date();
        String strDate = sdfDate.format(now);
        //time
          Calendar no=Calendar.getInstance();
         int hh= no.get(Calendar.HOUR_OF_DAY);
        if(hh>12)
            {
        hh=hh-12; 
        }
        int min=no.get(Calendar.MINUTE);
        int AP=no.get(Calendar.AM_PM);
        String apm="AM";
        if(AP == 1)
            {
        apm="PM";
        }
        //Converting Int time to String for inserting into DB
        String hht = Integer.toString(hh);
        String mint = Integer.toString(min);
        // Concating the hh mm and am/pm to give the rt formate
        String hhk=hht.concat(":");
        String mink=hhk.concat(mint);
        String ex_time=mink.concat(apm);
        //calculations
        int ord=Integer.parseInt(or_no);
        double mrp=Double.parseDouble(mr);
        int qtyt=Integer.parseInt(qty);
        int wh=Integer.parseInt(wth);
      //  int ttl=wh*qtyt;
        int free=Integer.parseInt(fre);
        double spl=Double.parseDouble(slp);
        double grs=spl*qtyt;
        int disper=Integer.parseInt(disp);
        double distamt=(grs*disper)/100; 
        double ntamt=grs-distamt;
        int vat=Integer.parseInt(vt);
        double vtamt=(ntamt*vat)/100;
        double total_amt=ntamt+vtamt;
        Class.forName("com.mysql.jdbc.Driver");
        String url=("jdbc:mysql://localhost:3306/warehouse?"+"user=root&password=123456");
        Connection con=DriverManager.getConnection(url);
        ResultSet rst=null;
        PreparedStatement stm = con.prepareStatement("insert into invoice(order_no,item_name,uom,wt,mrp,sp,fre,grs_amt,disc,disc_amt,net_amt,vat,vat_per,total_amt,invoice_date,exact_time,emp_name)  values(?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)");
        stm.setInt(1, ord);
        stm.setString(2, it_nam);
        stm.setString(3, um);
        stm.setInt(4, wh);
        stm.setDouble(5, mrp);
        stm.setDouble(6, spl);
        stm.setInt(7, free);
        stm.setDouble(8, grs);
        stm.setInt(9, disper);
        stm.setDouble(10, distamt);
        stm.setDouble(11, ntamt);
        stm.setInt(12, vat);
        stm.setDouble(13, vtamt);
        stm.setDouble(14, total_amt);
        stm.setString(15, strDate);       
        stm.setString(16, ex_time);    
        stm.setString(17, sman);    
        stm.executeUpdate();       
        ResultSet rs=null;
        PreparedStatement stmt=con.prepareStatement("select * from invoice where order_no=?");
        stmt.setInt(1, ord);
        rs=stmt.executeQuery();
     
      if(sel.equals("yes")){
           // HttpSession session=request.getSession(true);
            //session.setAttribute("order",or_no);
            return mapping.findForward(CONTI);/////// --------------------- go to above JSP
        } 
        return mapping.findForward(SUCC);
        
    }
}

[chaitanya karthikk]

Please format the code using ''code button''

[chaitanya karthikk]

Brother I am sorry to say that I don't know anything about struts. Some code phrases are confusing me.

[Mahesh Lohi]

Thanks a lot for your interest in solving my problem.

Happy Weekend