可以在 v$open_cursor中查询未关闭的cursor.

最好还是用完就关。

通过回答这一问题，请大家告诉我，我在发帖的时候写的那个函数在极度频繁被调用时可行吗？因为这个函数不处理任何close()操作，只是根据调用者的connection参数和String参数返回rs给调用者，在调用者的代码的最后会有rs.close()和connection.close()操作，但是肯定不会有st.close()。 那么这个未被显式地close()的st就是我一直不清楚的东西，在非常频繁地被重复这样调用（事实上这样的调用就象out.print（）一样多）后，DB端会是怎样一种情况？

摘录自 JDBC. 3.0 Specification，13.1.3 Closing Statement Objects

An application calls the method Statement.close to indicate that it has finished processing a statement. All Statement objects will be closed when the connection that created them is closed. However, it is good coding practice for applications to close statements as soon as they have finished processing them. This allows any external resources that the statement is using to be released immediately.

Closing a Statement object will close and invalidate any instances of ResultSet produced by that Statement object. The resources held by the ResultSet object may not be released until garbage collection runs again, so it is a good practice to explicitly close ResultSet objects when they are no longer needed.

These comments about closing Statement objects apply to PreparedStatement and CallableStatement objects as well.

public static ResultSet sysSelect(Connection conn,String sql)throws SQLException{
Statement st = null;
try{
st = conn.createStatement();
ResultSet rs = st.executeQuery(sql);
return rs;
}catch (SQLException ex){
throw ex;
}finally{
if (null!=st) st.close();
}
}

to glassprogrammer: 关闭连接后还能使用rs的讨论，我在其他地方看到过类似的讨论，可是我以前在DB2、ORACLE812上测试的结果都是行不通的！不知道你是在哪里设置了这一特性？ 不过对于使用conn.createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability)的最后一个参数可以做到这一点！ 但是这是jdbc3.0里的功能，我现在所在的都是IBM的环境，IBM自带的JDK只相当于sun jre1.3.1的版本，是没有这个功能所以也无法测试。

try{
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
for (int i=0; i<100; i++){
Connection conn = DriverManager.getConnection(
"jdbc:microsoft:sqlserver://Akun:1433;databaseName=bookstore", "sa",
"");
Statement stm = conn.createStatement();
ResultSet rs = stm.executeQuery("Select * from Book");
//stm.close();
conn.close();
}
执行后,在SQL查询分析器里sp_who,不占连接啊.