SQL place holders will not bind

Question

I just need a second set of eyes on this as mine are not able to see the mistake.The insert is not working and I can't see why. This is for a homework assignment. The applicable code is inside the CustomerDAO class. This is for a webapp built with Java using the Stripes framework. Here is the offending code:

public void create(Customer customer) {
    String sql = "insert into customer (`firstname`, `lastname`, `email`, " +
            "`username`, `password`) values (?, ?, ?, ?, ?)";   
    try {
        PreparedStatement sth = this.dbh.getCon().prepareStatement(sql);
        sth.setString(1, customer.getFirstName());
        sth.setString(2, customer.getLastName());
        sth.setString(3, customer.getEmailAddress());
        sth.setString(4, customer.getUserName());
        sth.setString(5, customer.getPassword());
        sth.executeUpdate();
    } catch (SQLException e) {
        e.printStackTrace();;
    } catch (NullPointerException ex) {
        ex.printStackTrace();
    } finally {
        this.dbh.closeConnection();
    }

}

As I said this method resides in my DAO. This method is called from an action bean for the registration form. Here are the things I have tested for:

The customer object is not null. The customer fields are getting their values from the form and they are correct. The DAO is not null. The database is connected.

I checked the items above by testing the condition in the Action Bean and returning null if the condition was true, otherwise I returned the RedirectResolution.

I did comment out the five lines that bind the variables to the SQL and replaced the variables in the SQL with the actual data I wanted to insert and the record did insert. That is why I believe the problem is somewhere in these five lines:

sth.setString(1, customer.getFirstName());
sth.setString(2, customer.getLastName());
sth.setString(3, customer.getEmailAddress());
sth.setString(4, customer.getUserName());
sth.setString(5, customer.getPassword());

When I used this if statement in the action bean I was redirected to a completely empty page which is how I know that the values are bound to the model's fields.

if (this.customer.getFirstName().equals("Tony")) {
    return null;
}

Here is the submit method from the action bean:

public Resolution submit() {
    this.customer = this.getCustomer();
    this.customerDao = this.getCustomerDao();
    this.customerDao.create(customer);
    return new  RedirectResolution(RegisterFormActionBean.class);
}

The test for the field values was inserted under this.customer = this.getCustomer();. I ran that test independently on all of the form fields and it always forwarded to a blank page. When this runs I am redirected back to the registration page but the record is not inserted. I checked the documentation to make sure that the setString() method is right and it appears to be.

I know it is probably something silly that I am overlooking but I am just spinning my wheels here.

Actual question: Why does the insert work when I hard code the values into the SQL but it doesn't work when I bind values to the statement.

Answer 1

I figured it out. On a hunch I changed my database table to accept NULL except for the id field. When I ran it again the record inserted and I saw that the 'password' field was NULL. I have two password inputs on the register.jsp page, both named 'password'. Apparently Stripes doesn't know what to do if you have duplicate names on the same form, I thought one would overwrite the other. I renamed one of the text boxes to "" and changed the database table back to not allowing NULL and the record inserted.

Answer 2

Perhaps your transactions are not being autocommitted. Verify how your dbh object is creating connections and see if they are disabling autocommit. Try enabling autocommit with this:

Connection myConnection = this.dbh.getCon();
myConnection.setAutoCommit(true);
myConnection.prepareStatement(sql);

See http://docs.oracle.com/javase/tutorial/jdbc/basics/transactions.html for more info.