• 使用ColumnListHandler

public static void columnListHandler() throws SQLException {
        Connection con = MyJDBCUtiles.getConnection();
        QueryRunner qr = new QueryRunner();
        String sql = "select username,password from userinfo where age = ?";
        //注意sql語句中的篩選項(username,password)一定要包括下列list中的引數項(username)
        Object [] param = {29};
        List<Object> list = qr.query(con,sql,new ColumnListHandler<Object>("username"),param);
        //若沒有查詢到則list.size()=0
        for (Object o : list){
            System.out.println(o + "\t");
        }
    }

• 結果

• 使用ScalarHandler

public static void scalarHandler() throws SQLException {
        Connection con = MyJDBCUtiles.getConnection();
        String sql = "select count(*) from userinfo where age = ?";
        QueryRunner qr = new QueryRunner();
        Object [] param = {21};
        long o = qr.query(con,sql,new ScalarHandler<Long>(),param);
        //若未查詢到，則o的值為0
        System.out.println(o);
    }

• 結果