Hi!
I am trying to make Java servlets connect to a Mysql database. My first servlet connects to the MySQL database. This works fine. When I proceed to the next servlet my database connection is NULL, and I get a NULLPOINTER Exception in Tomcat. I think the problem is that I am not correctly "forwarding" the db connection correctly from the previous servlet.
The code for my first Servlet looks like this:
public class EnterServlet extends HttpServlet {
private DatabaseDezign db;
public void init() {
String user = getInitParameter("User");
String password = getInitParameter("Password");
db = new DatabaseDezign();
db.openConnection(user, password);
}
public void destroy() {
db.closeConnection();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
if(db.getConnection()!=null) {
response.sendRedirect("/krusty/cannotConnect.html");
return;
}
/
--- change 'db.userExists' below to the call that you ---
--- make in your implementation of Database in order ---
--- to check if a user exists in the database ---
/
HttpSession session = request.getSession(true);
session.setAttribute("db", db);
//session.setAttribute("userId", userId);
String mainURL = response.encodeRedirectURL("/krusty/Main");
// don't know if encodeRedirectURL is necessary
response.sendRedirect(mainURL);
}
}
And this is the code for my second servlet which I am redirected to from above servlet:
public class MainServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
HttpSession session = request.getSession(false);
if (session == null) {
response.sendRedirect("/krusty/lostSession.html");
return;
}
DatabaseDezign db = (DatabaseDezign) session.getAttribute("db");
//db.openConnection("usman", "944knoim");
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<head><title>Dezign</title></head>");
out.println("<body BGCOLOR=#82CAFF>");
out.println("<h1 align=center>Dezign</h1>");
out.println("<h2 align=left>"+db.getConnection()+"</h2>"); // **THIS RETURNS NULL**
out.println("<p>");
out.print("<form method=post action=\"");
out.print(response.encodeURL("/krusty/Product"));
out.println("\">");
Now the question is; Why is the connection NULL on the second servlet and how do I "forward" the connection. Maybe it has something to do with the Session attribute, that is where I am "sending" the Database object. Anyone please help me with this, I have tried to solve this without any luck.
Look forward for response!