mysql添加添加两次_MySQL在Java中两次插入数据

我试图将数据从另一个表(购物车)插入到表(order_details)中.当我执行此操作时,它在数据库中插入了两次数据.我不知道为什么会这样.有谁能够帮助我？提前致谢.

CartDAO

public boolean insertCart(String username)

{

try

{

sql = "INSERT INTO order_details (username, product_code, product_name, qty, product_price, product_pic, order_status)"

+"SELECT username, product_code, product_name, qty, product_price, product_pic, order_status FROM cart WHERE username = ? AND order_status = 1";

con = DbConnection.getConnection();

pst = con.prepareStatement(sql);

pst.setString(1, username);

pst.executeUpdate();

DbConnection.close();

return true;

}catch(ClassNotFoundException | SQLException ex)

{

Logger.getLogger(CartDAO.class.getName()).log(Level.SEVERE, null, ex);

return false;

}

}

CartWS

public boolean insertOrderDetails(String username)

{

CartDAO dao = new CartDAO();

return dao.insertCart(username);

}