java-获取数字数据库值

Question

你好我正在研究一个java代码,它假设得到我正在处理的用户配置文件表中的用户总数.现在我确信我的sql语句是正确的但由于某种原因我不知道如何从中获取数值.任何帮助都非常感谢和欢迎.我相信我试图获得价值的方式不起作用,但我不知道如何获得价值,这是下面的代码,谢谢你:

     public int getUserCount() throws SQLException {    

    Connection conn = null;
    Statement stmt = null;
    ResultSet rs = null;
    double encinfo;
    conn = DAOFactory.getDatabaseDAO().getConnection();
        StringBuffer query = new StringBuffer();
        query.append( "Select COUNT (DISTINCT record_id)");
        query.append( "From USER_PROFILE");
        stmt = conn.createStatement();
        rs = stmt.executeQuery( query.toString());
        if (!rs.next())
           throw new SQLException( SQLException.User_NOT_FOUND,"No User Count found.");

        // Should be able to get the user amount or value or total users in DB.
        userInfo = rs.getDouble( "USER_VALUE");

        m_userCount = (int) userInfo;
   }

Answer 1

这可能有效:

添加别名以记录计数:

  query.append( "Select COUNT (DISTINCT record_id) AS USER_VALUE");
        query.append( " From USER_PROFILE");

另一种方式可能是:

rs.getDouble(1);

这里1是列的索引.