login page enter correct username and password

Question

The login page displays an error message indicating failure to login, even when the correct username and password combination is entered. What is the cause of this problem?

try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection conn = DriverManager.getConnection("jdbc:odbc:mydsn","sa","password@123");
String sql = "select customer_id, fname, lname, email_id, phone_number from customer_details where user_name=? and password=?";
PreparedStatement stmt;
ResultSet rs = stmt.executeQuery();
if (rs.next()) {
session.setAttribute("customerId", rs.getString(1));
session.setAttribute("userName", userName);
session.setAttribute("fName", rs.getString(2));
session.setAttribute("lName", rs.getString(3));
session.setAttribute("emailId", rs.getString(4));
session.setAttribute("phoneNumber", rs.getString(5));
conn.close();
%>
<jsp:forward page="welcome.jsp" />
<%} else {%>
Sorry! You have entered an invalid username or password. Please try again.
<%}
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

Answer 1

it is because

PreparedStatement stmt;
ResultSet rs = stmt.executeQuery();

stmt is null

Few suggestions for your code:

• Avoid java code in jsp
• write java code in servlet
• Handle exceptions properly