java - 选择位置查询的JDBC问题

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ResultSet exception - before start of result set
                                
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我的代码：

con = jdbc.connect();
        System.out.println("status of con"+con);
String query = " select * from BmgCPUTotalUsage where CPUserID='"+CPUserID+"' and MessageTypeID='"+MessageTypeID+"'";
        System.out.println(query);
        PreparedStatement statement = con.prepareStatement(query);
    ResultSet result = statement.executeQuery();
    System.out.println(result);
    int QuotaUsed=result.getInt("QuotaUsed");

输出：

   status of concom.mysql.jdbc.JDBC4Connection@182600f
     select QuotaUsed from BmgCPUTotalUsage where CPUserID='msdp' and MessageTypeID='SMS'
    com.mysql.jdbc.JDBC4ResultSet@16e1dd8
    java.sql.SQLException: Before start of result set.

有人可以告诉我如何删除此异常。并从表中获取QuotaUsed。其中QuotaUsed是整数。

最佳答案

您确实需要对JDBC Tutorial进行更多阅读，但是请简要尝试一下：

ResultSet resultSet = statement.executeQuery();
if (resultSet.next() {
    int quotaUsed = resultSet.getInt("QuotaUsed");
}