finally出错！该如何使用？

伟大de虫子 2003-10-06 10:23:18

下面代码运行正常：
———————————————————————————

<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.sql.*"%>
<html>
<body>
SQLserver连接测试： 

<%
try
{
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
String connstr="jdbc:microsoft:sqlserver://arbiter:1433;DatabaseName=test";

Connection conn= DriverManager.getConnection(connstr,"aa","123456");
Statement stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
String sql="select * from aa_user";
ResultSet rs=stmt.executeQuery(sql);
while(rs.next())
{
out.print(" " + rs.getString(1));
out.print("," + rs.getString(2));
out.print("," + rs.getString(3));
}
out.print(" 数据库操作成功，恭喜你");
}
catch(Exception ex)
{
out.print("error:"+ex.toString());
}
rs.close();
stmt.close();
conn.close();
%>
</body>
</html>

为了能在抛出异常时也能关闭数据库的连接，节省资源，把上面的
rs.close();
stmt.close();
conn.close();
改成如下代码：

finally
{
if(rs!=null){
try{rs.close();}
catch(Exception rs_err){out.print("error:"+rs_err.toString());}
}
if(stmt!=null){
try{stmt.close();}
catch(Exception stmt_err){out.print("error:"+stmt_err.toString());}
}
if(conn!=null){
try{conn.close();}
catch(Exception conn_err){out.print("error:"+conn_err.toString());}
}
}

改了之后，出现下面的错误：
500 Servlet Exception
/sqltest.jsp:55: cannot resolve symbol
symbol : variable rs
location: class _sqltest__jsp
if(rs!=null){
^
/sqltest.jsp:57: cannot resolve symbol
symbol : variable rs
location: class _sqltest__jsp
try{rs.close();}
^
/sqltest.jsp:63: cannot resolve symbol
symbol : variable conn
location: class _sqltest__jsp
if(conn!=null){
^
/sqltest.jsp:65: cannot resolve symbol
symbol : variable conn
location: class _sqltest__jsp
try{conn.close();}
^
4 errors

无论怎么改都改不好，请大家帮帮忙，感激！

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