every variable declared in the declaration tag <%! .... %> is a class level variable... that means its going to be shared by all the threads, u might have some volatile data, unless u synchronize it...
just declare ur variables within a scriplet tag <% .. %> with out the " ! "..... hope that helps Amit -----Original Message----- From: A mailing list about Java Server Pages specification and reference [mailto:JSP-INTEREST@;JAVA.SUN.COM]On Behalf Of Daniel Sent: Wednesday, November 13, 2002 2:33 AM To: [EMAIL PROTECTED] Subject: Thread Doubt and Multi User Environment Hi, I have a JSP code like this and this is converted into a servlet. What happens when multiple user tries to access the code, I have written the jsp code down and the servlet equivalent is also given. Is it a bad to write the variables as private. What happens when multiple user try to access the same jsp page. Is it safe for multi user environment? Is it really a bad code for multi user environment? Since the variables are declared private! Regards, Daniel.E /*********************JSP code ******************************************/ <% try { //Get session variable and check authorization Integer n_user_id = (Integer)session.getAttribute("n_user_id"); Integer n_group_id = (Integer)session.getAttribute("n_group_id"); if(n_user_id == null || n_group_id.intValue() != 1) { response.sendRedirect("../../../login/index.jsp"); return; } } catch(Exception e) { response.sendRedirect("../../../login/index.jsp"); return; } %> <HTML> <HEAD> <meta http-equiv="Content-Type" content="text/html; charset=Shift_JIS"> <link rel="stylesheet" href="../../../../stylesheet/styleMori.css" type="text/css"> <TITLE>New User</TITLE> </HEAD> <BODY> <%@ page language="java" contentType ="text/html;charset=Shift_JIS" %> <!-- All imports used in this JSP file --> <%@page import="java.sql.DriverManager" %> <%@page import="java.sql.Connection" %> <%@page import="java.sql.PreparedStatement" %> <%@page import="java.sql.Statement" %> <%@page import="java.sql.ResultSet" %> <%@page import="java.io.StringWriter" %> <%@page import="java.io.PrintWriter" %> <%@page import="com.mustang.dbutil.DbConnection" %> <%@page import="com.mustang.sqlutil.SQLParam" %> <!-- Variables Declaration --> <%! private String loginid = null; %> <%! private String pass = null; %> <%! private String fname = null; %> <%! private String gname = null; %> <%! private String email = null; %> <%! private String access_level = null; %> <%! private int access = 0; %> <%! private StringWriter sw = new StringWriter(); %> <%! private PrintWriter pw = new PrintWriter(sw); %> <%! private DbConnection db = null; %> <%! private Connection con = null; %> <%! private PreparedStatement pstmt = null; %> <%! private Statement stmt = null; %> <%! private ResultSet res = null; %> <% //aquire variables try { access = Integer.parseInt(request.getParameter("access")); loginid = request.getParameter("loginid"); pass = request.getParameter("pass"); fname = request.getParameter("fname"); gname = request.getParameter("gname"); email = request.getParameter("email"); if(loginid == null || pass == null || request.getParameter("access") == null || fname == null || gname == null || email == null) { /********************************Servlet Code ******************/ package org.apache.jsp; import java.sql.DriverManager; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.Statement; import java.sql.ResultSet; import java.io.StringWriter; import java.io.PrintWriter; import com.mustang.dbutil.DbConnection; import com.mustang.sqlutil.SQLParam; import javax.servlet.*; import javax.servlet.http.*; import javax.servlet.jsp.*; import org.apache.jasper.runtime.*; public class newUserProcessAd$jsp extends HttpJspBase { // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(61,3);t o=(61,35)] private String loginid = null; // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(62,3);t o=(62,32)] private String pass = null; // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(63,3);t o=(63,33)] private String fname = null; // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(64,3);t o=(64,33)] private String gname = null; // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(65,3);t o=(65,33)] private String email = null; // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(66,3);t o=(66,40)] private String access_level = null; // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(68,3);t o=(68,28)] private int access = 0; // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(70,3);t o=(70,50)] private StringWriter sw = new StringWriter(); // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(71,3);t o=(71,50)] private PrintWriter pw = new PrintWriter(sw); // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(73,3);t o=(73,36)] private DbConnection db = null; // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(75,3);t o=(75,35)] private Connection con = null; // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(76,3);t o=(76,44)] private PreparedStatement pstmt = null; // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(77,3);t o=(77,35)] private Statement stmt = null; // end // begin [file="/jspsource/admin/user/newuser/newUserProcessAd.jsp";from=(78,3);t o=(78,34)] private ResultSet res = null; // end static { } public newUserProcessAd$jsp( ) { } private static boolean _jspx_inited = false; public final void _jspx_init() throws org.apache.jasper.runtime.JspException { } public void _jspService(HttpServletRequest request, HttpServletResponse response) throws java.io.IOException, ServletException { JspFactory _jspxFactory = null; PageContext pageContext = null; HttpSession session = null; ServletContext application = null; ServletConfig config = null; JspWriter out = null; Object page = this; String _value = null; try { if (_jspx_inited == false) { synchronized (this) { /********************************Servlet Code ******************/ =========================================================================== To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST DIGEST". Some relevant FAQs on JSP/Servlets can be found at: http://archives.java.sun.com/jsp-interest.html http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.jsp http://www.jguru.com/faq/index.jsp http://www.jspinsider.com =========================================================================== To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST DIGEST". Some relevant FAQs on JSP/Servlets can be found at: http://archives.java.sun.com/jsp-interest.html http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.jsp http://www.jguru.com/faq/index.jsp http://www.jspinsider.com
