Hashtable问题?

[zyfire88]

import java.util.*;
import java.sql.*;

public class table {
private Connection con;
private Statement sta;
private ResultSet rs;
private ResultSet rs1;
private Hashtable has=new Hashtable();
private Hashtable ha=new Hashtable();
private class authors{
String au_id;
String au_lname;
String au_fname;
}
private class titles{
String title_id;
String title;
}
public table(){
try{
String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=pubs";
String user="sa";
String pwd="sa";
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
con=DriverManager.getConnection(url,user,pwd);
System.out.println("ok");
sta=con.createStatement();
rs=sta.executeQuery("select au_id,au_lname,au_fname from authors");
while(rs.next()){
authors author=new authors();
author.au_id=rs.getString(1);
author.au_lname=rs.getString(2);
author.au_fname=rs.getString(3);
System.out.println(author.au_id+" ");
rs1=sta.executeQuery("select title_id,title from titles where title_id in(select title_id from titleauthor where au_id='"+author.au_id+"')");
while(rs1.next()){
System.out.println(rs1.getString("title_id"));
titles title=new titles();
title.title_id=rs1.getString(1);
title.title=rs1.getString(2);
System.out.println(title.title=rs1.getString(2));
ha.put(title.title_id,title.title);
}
rs1.close();
has.put(author.au_id,ha);
}
rs.close();
con.close();
}
catch(Exception ex){
System.out.println("err");
}
}
public static void main(String args[]){
new table();
}
}


不知道哪出了错,请大家帮忙,谢!

[kingofhawks]

老大，什么错都不说，让人家怎么帮你看哪出错阿？

[xiaobzg]

什么异常？runtime异常这里不好判断，用debug查
另外 rs.close();
con.close();
写在finally里

[chg2008]

晕死，好歹把错误提示给弄出来吧

[zyfire88]

不好意思

这是错误信息:
java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Object has been closed.
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BaseResultSet.validateClosedState(Unknown Source)
at com.microsoft.jdbc.base.BaseResultSet.commonFetchInitialize(Unknown Source)
at com.microsoft.jdbc.base.BaseResultSet.next(Unknown Source)
at table.<init>(table.java:30)
at table.main(table.java:56)

[franckjun]

Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
看看有没有sun.jdbc.odbc.JdbcOdbcDriver这个驱动，用这个或许可以。

[zyfire88]

我不是连接数据库的问题,是
while(rs.next()){
authors author=new authors();
author.au_id=rs.getString(1);
author.au_lname=rs.getString(2);
author.au_fname=rs.getString(3);
System.out.println(author.au_id+" ");
rs1=sta.executeQuery("select title_id,title from titles where title_id in(select title_id from titleauthor where au_id='"+author.au_id+"')");
while(rs1.next()){
System.out.println(rs1.getString("title_id"));
titles title=new titles();
title.title_id=rs1.getString(1);
title.title=rs1.getString(2);
System.out.println(title.title=rs1.getString(2));
ha.put(title.title_id,title.title);
}
rs1.close();
has.put(author.au_id,ha);
}

外面一层循环好象循环一次后就有异常发生,不再做循环了

[gongxsh00]

应该是数据库操作的问题，你再用一个Statement试试。ResultSet中并不直接存储查找到的结果，对象里有一个Statement，所以，两个ResultSet都指向了同一个Statement，内循环的查询影响了外循环的结果。

[yuzl32]

System.out.println(author.au_id+" ");
rs1=sta.executeQuery
... ...

改:
System.out.println(author.au_id+" ");
Statement stmt = con.createStatement();
rs1=stmt.executeQuery

... ...

PS: 内循环完记得马上释放stmt.

[zyfire88]

恩,可以了,是Statement的问题 谢了!!!