Question

我的代码有问题：错误：ORA-01000：超出最大打开光标。从多个线程调用此代码。问：oracle游标是否与JDBC游标（结果集）不同？

public static void viewTable(Connection con, String TBName)
        throws SQLException {

        Statement stmt = null;
        String query =   "select *from " + TBName;

        try {
            stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery(query);
            while (rs.next()) {
                String studentName = rs.getString("STD_NAME");

                System.out.println(studentName + "\t");
            }
        } catch (SQLException e ) {
            e.printStackTrace();
        } finally {
            if (stmt != null) { stmt.close(); }
        }
    }

Answer 1

您应该始终关闭ResultSet和Statement。正如您所说，您的代码可以被许多线程访问，因此很多Resultset将是开放的，永远不会闭合。

将ResultSet变量放在try catch块之外，并在Statement结束旁边的finally中关闭它。

Answer 2

使用try-with-resources确保语句和结果集都已关闭。

    String query =   "select STD_NAME from " + TBName;
    try (Statement stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery(query)) {
        while (rs.next()) {
            String studentName = rs.getString("STD_NAME");
            System.out.println(studentName + "\t");
        }
    } // Closes rs and stmt even with exceptions.

最大打开游标超过了java和oracle中的异常

2 个答案: