oracle中返回主键值

在今天的ATM中，就用纯粹的jdbc来处理数据，当发现用user ，card，log之间的关系，在save用户之后，要用到user中id来关联到card中，的字段，而oracle中插入和跟新之后是返回的插入和更新的行数，后来想了想，也上网搜了一些资料，现在总结如下，

/**
     * 添加用户
     */
    @Override
    public int save(User user)
    {
        temp = -1;
        final String sql = "insert into atm_user(username,password,sex,idCard) values(?,?,?,?)";

        try
        {
           String key[] =
            { "id" };
            ps = this.conn.prepareStatement(sql, key);
            ps.setString(1, user.getUsername());
            ps.setString(2, user.getPassword());
            ps.setString(3, String.valueOf(user.getSex()));
            ps.setString(4, user.getIdCard());
            temp = ps.executeUpdate();
            System.out.println(temp);

            rs = ps.getGeneratedKeys();
            rs.next();
            if (temp > 0)
            {
                temp = Integer.valueOf(rs.getString(1));
            }

        } catch (SQLException e)
        {
            e.printStackTrace();
            try
            {
                conn.rollback();
            } catch (SQLException e1)
            {
                e1.printStackTrace();
            }
        } finally
        {
            close();
        }
        return temp;
    }