JDBC always tests the last row of MySQL table?

Question

I have a Manager class that saves data in the SQL table and also get result from SQL table and test these data.when I run my program,one frame will be shown that gets ID and pas

Answer 1

The simple answer is that your while loop should terminate when you find a match, so it should read:

    while (rst.next() && bool == false) {
        if (rst.getString(1).equalsIgnoreCase(userName) && rst.getString(2).equalsIgnoreCase(password)) {
            bool = true;
        }
    }

Note that it would be more efficient to select only rows that match your user id & password, something along the lines of the following: (note that error handling is left as an exercise for the reader)

PreparedStatement stmt; stmt = conn.prepareStatement("SELECT yahooId , password FROM clienttable WHERE yahooId = ?"); stmt.setString(1, "userName");
ResultSet rst = null; rst = stmt.executeQuery();

if (rs != null && rs.getString("password").equals(password)) { bool = true; }