Java EE (Java Enterprise Edition) General Discussion

Hi:
I use html+ servlet +jsp to insert data(like SSN address...) into member registration table and forward data back to browns. Since,I set SSN as primary key so when the input ssn is uniqe everything work fine, but my program can't forward error message to jsp file when ssn is already in table. what do I do wrong in my code ?

/////////////////////////////////////////

public void doPost(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {

res.setContentType("text/html");
PrintWriter out = res.getWriter();

try {


//Get the incoming data parameters from the client
String NewSSN =req.getParameter("SSN");
String Fname =req.getParameter("Fname");

String ErrMsg = "";


conn = DriverManager.getConnection( "jdbc:microsoft:sqlserver://localhost:1433; DatabaseName=airplanes","****","*****" );
DatabaseMetaData md = conn.getMetaData();
stmt = conn.createStatement(
ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_READ_ONLY);

rs = stmt.executeQuery("select SSN FROM OurMembers ");

// user information will be insert into our database
//if we can't find your ssn in our database

while(rs.next()) {
if (NewSSN = SSN){
ErrMsg ="you registrate before or you don't enter the right SSN";
req.setAttribute("ErrMsg",ErrMsg);}

else{
stmt.executeUpdate("INSERT INTO OurMembers ("
+ "SSN, Fname)"
+ "VALUES('"
+ NewSSN + "','"
+ Fname + "'"
+ ")");


//get current session, create if it doesn't exits
HttpSession userSession = req.getSession(true);
userSession.setAttribute("SSN", NewSSN);
userSession.setAttribute("Fname", Fname);

}

}//end of while


RequestDispatcher disp;
disp = getServletContext().getRequestDispatcher("/Welcome.jsp");

disp.forward(req, res);
}//end try


catch(SQLException e) {

}

finally {
try {
if(rs != null)
{
rs.close();
rs = null;
}
if(stmt != null)
{
stmt.close();
stmt = null;
}
if(conn != null)
{
conn.close();
conn = null;
}
} //end try
catch (SQLException e) {}

}//end finally
}

}
Thank you