需要一些逻辑帮助. [英] Need some logic help.

问题描述

我正在做一些"while"循环，但是有点卡在某个地方.

我要做的实际上是从2个数据库表中进行比较.

现在的问题例如，我在SMS_IN表中有10条记录，但是我的代码每次调用它时都只运行第一条记录.正确，它应该遍历所有数据并进行检查.

SMS_IN(样本数据)

originator |文字|日期
88411254 |互联网bla bla bla | 8月5日
78412447 |测验ans1 ans2 ans3 | 8月5日

USERAPP(示例数据)

userid |关键字
54 |互联网
80 |测验

所以逻辑是首先将检查SMS_IN文本列，例如第一个结果的第一个单词是"Internet"，然后将检查USERAPP关键字列，如果关键字是"Internet" ''存在，表示其有效的短信.如果USERAPP表中根本不存在该关键字，则将从SMS_IN表中删除该消息.

这是我的代码

Hi people, i am doing some ''while'' loop but kinda stuck somewhere.

What i want to do is actually is comparing from 2 database tables.

The problem now is example i have 10 records in SMS_IN table, but my code only runs the first record everytime i calls it. By right, it should loop thru all the data and check.

SMS_IN (sample data)

originator | text | date
88411254 | Internet bla bla bla | 5 August
78412447 | Quiz ans1 ans2 ans3 | 5 August

USERAPP (sample data)

userid | keyword
54 | Internet
80 | Quiz

So the logic is first it will check the SMS_IN text column, example the first word of the first result is ''Internet'', then it will check the USERAPP keyword column, if the keyword ''Internet'' exists, means its a valid sms. If the keyword does not exists at all in the USERAPP table, the msg will be deleted from SMS_IN table

this is my code

ResultSet rs = null;<br />        ResultSet rs2 = null;<br />        String sql = "Select * from smsserver_in";<br />        String sql1 = "Select * from USERAPP";<br />        rs = db.SelectDB(sql);<br />        rs2 = db.SelectDB(sql1);<br /><br />        try {<br />            String firstword = null;<br />            String keyword = null;<br />            int number = 0;<br />            while (rs.next()) {<br />                StringTokenizer st = new StringTokenizer(rs.getString("text"));<br />                firstword = st.nextToken();<br />                //out.println("1"+firstword);<br />                number = rs.getInt("id");<br /><br />                while (rs2.next()) {<br />                    keyword = rs2.getString("keyword");<br />                    //out.println("2"+keyword);<br />                    if (firstword.equals(keyword)) {<br />                        out.println(number);<br />                        String sql3 = "Insert into app_" + keyword + "(originator,text)values(" + rs.getString("originator") + ",''" + rs.getString("text") + "'')";<br />                        db.InsertDB(sql3);<br />                        String sql4 = "delete from smsserver_in where id=" + number;<br />                        db.UpdateDB(sql4);<br />                    } else {<br /><br />                    }<br /><br />                }<br /><br />            }<br />        } catch (Exception ex) {<br />        }<br />    }

推荐答案

您的代码是错误的，它有两个嵌套循环，但就像只有一个循环一样.
这是一个非常简单的代码段，存在相同的问题，它应该可以帮助您理解问题所在:

Hi,

your code is wrong, it has two nested loops but acts as if there were only one loop.
Here is a very simple snippet with the same problem, it should help you in understanding what goes wrong:

<br />int i1=0;<br />int i2=0;<br /><br />for (; i1<10; i1++) {<br />    for (; i2<10; i2++) {<br />        Console.WriteLine("i1="+i1+"  i2="+i2);<br />    }<br />}<br />

现在想象您手动执行此代码.如果仍然看不到，请运行该代码.然后使用调试器，设置断点，然后学习.
如果您发现了这一点，很可能就不会再犯同样的错误了.

:)

Now imagine you executing this code by hand.
If you still don''t see it, run the code. Then use the debugger, set a breakpoint, and learn.
If you discover this, chances are you won''t make the same mistake ever again.

:)

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