StringBuffer and PreparedStatement

Question

Does anyone know why prepared statements don't update ? fields when you provide the preparedstatement with a query that is a stringbuffer?
i.e.
StringBuffer query = new StringBuffer(500);
query.append("SELECT * from Customer WHERE CustId = ?");
    try{
                      pstmt = conn.prepareStatement(
                           query.toString()
                pstmt.setInt(1, 2);
                result = pstmt.executeQuery();

Answer 1

Why are you doing this?
StringBuffer query = new StringBuffer(500);I am doing this before i have to dynmically manipulate the query, i have an array which i have to loop around and keep adding to the query till i get to the end. I cannot do this by simply specifiying the query inside the prepared statmenet paramaeter. The question mark parameters have nothing to do with adding to the query, it works fine if i specify the actual fields CustID = 1; instead of CustID = ?;
SO my actual point was simply:
I want to following query inside a string buffer where i can specifiy the paramaeters at a later stage using setInt, setString etc.
SELECT * from Customer WHERE CustId = ?
System.out.println(query.toString()); gives:
SELECT * from Customer WHERE CustId = ?Now the string buffer, I'm specifiy the query reference directly to the preparedsttement i.e. this would be the same if i did conn.preparedStatment(SELECT * FROM CUSTOMER WHERE CustID = ?);
try{
                      pstmt = conn.prepareStatement(
                           query.toString()
                 );After i use pstmt.setInt(1, 2);
i get:
SELECT * from Customer WHERE CustId = ?when it should be:
SELECT * from Customer WHERE CustId = 2