doGet

[Lucky Singh]

If I have a servlet called LoginServlet that accepts username and password
and I display this form in the doGet() method, when I submit this form I want doGet() of LoginServlet to be called again so that it can check with database .
But won't the username and password be null this time?
What must I do to prevent it from becoming null the second time I call doGet()?

[Jeanne Boyarsky]

I'm not sure I'm understanding this right. Wouldn't it be null the first time and not the second time? It sounds to me like the first time, you display the form (and the userid/password are not known yet.)
In general, if you want to remember attributes, you can store them in the session.

[Lucky Singh]

How do I do that?

[Scott Duncan]

You can also pass it back and forth in in the request using request.setAttribute in the servlet and request.getAttribute in the JSP. You'll need the RequestDispatcher object to forward the request back to the JSP though.
One thing I do not understand is the use of the GET in the form which will subsequently call the doGet method of the servlet. Choosing GET as the method in the form will append all of the data to the URL and it will show up in the URL bar of your browser. This doen't seem like something you'd want to do for a login screen. I'd use POST instead.

[Sekhar Kadiyala]

HttpSession session = request.getSession();
UserInfo ud = (UserInfo) session.getAttribute("user"); //user is just a attribute name.
ud= new UserInfo();
session.setAttribute("user",ud);
ud.setUserid(request.getParameter("userid"));
ud.setPassword(request.getParameter("password"));

From then on whereever you want to use these details, like in JSP or any other servlet you can type the following get the details

UserInfo ui = (UserInfo) session.getAttribute("user");

UserInfo class

public class UserInfo {
private String userid;
private String password;

public void setUserid(String uid)
{
userid=uid;

}

public void setPassword(String pwd)
{
password=pwd;

}
public String getUserid()
{
return userid;

}

public String getPassword()
{
return password;

}
}

Hope this helps

[Sekhar Kadiyala]

The first piece of code you need to write in the logon servle.
In the Logon servlet, you can put the code after the userid/password validation.