Question

我正在接受＆＃34; java.sql.SQLException：ResultSet关闭后不允许操作＆＃34;例外。我用谷歌搜索它，它说当我们有几个属于同一个Statement的ResultSet时它会导致它。但在我的代码中，我为每个ResultSet使用不同的Statement，但我仍然看到这个问题。这是我的代码。 Frist Code 。

    ResultSet rs = null;
    PreparedStatement pstmt = null;
    try {
        pstmt = getPreparedStatement(sql);
        rs = (ResultSet) pstmt.executeQuery();
        while (rs.next()) {
            PreparedStatement pstmt1 = null;
            ResultSet rs1 = null;
            if (condition) {
            } else {
                if (condition) {
                    int index = 0;
                    String newSql = "query";
                    pstmt1 = getPreparedStatement(newSql);
                    rs1 = (ResultSet) pstmt1.executeQuery();
                    if (rs1.next()) {
                    }
                }
            }
            closeAll(pstmt1, rs1);
        }
    } finally {
        closeAll(pstmt, rs);
        closeConnection();
    }

这是我的基本连接类代码

Connection conn = null;
boolean isfromPool = false;
Vector connectionavailable = new Vector();

/**
 *
 * @return
 * @throws java.sql.SQLException
 */
private Connection getConnection() throws SQLException {
    try {

        Context initContext = new InitialContext();
        //DataSource ds = (DataSource) initContext.lookup("java:comp/env/jdbc/TestDB");

        Context envContext = (Context) initContext.lookup("java:comp/env");
        if (envContext == null) {
            ApplicationLogger.log("envContext is null. unable to get connection from pool");
            throw new Exception("envContext is null. unable to get connection from pool");
        }
        DataSource ds = (DataSource) envContext.lookup("jdbc/CI");
        if (ds == null) {
            ApplicationLogger.log("DataSource is null. unable to get connection from pool");
            throw new Exception("DataSource is null. unable to get connection from pool");
        }

        conn = ds.getConnection();

        if (conn == null) {
            ApplicationLogger.log("connection object is null that taken "
                    + "from connection pool");
        } else {
            if (conn.isClosed()) {
                ApplicationLogger.log(Level.INFO, "Connection object is closed that taken from pool");
                throw new Exception("Connection object is closed that taken from pool");
            }
            isfromPool = true;
            return conn;
        }
    } catch (Exception e) {
        ApplicationLogger.log(Level.SEVERE, "unable to get the connection", e);
        throw e;
    } finally {
        return conn;
    }


}

/**
 *
 * @return
 * @throws java.sql.SQLException
 */
private Statement getStatement() throws SQLException {
    return getConnection().createStatement();
}
public PreparedStatement getPreparedStatement(String sql) throws SQLException {
    ApplicationLogger.log(Level.ALL, "SQl is : " + sql);
    // return (PreparedStatement) getConnection().prepareStatement(sql);
    return (PreparedStatement) getConnection().prepareStatement(sql);
}

public void closeAll(PreparedStatement pstmt, ResultSet rs) throws SQLException {
    if (rs != null) {
        rs.close();
        rs = null;
    }
    if (pstmt != null) {
        pstmt.close();
        pstmt = null;
    }
    if (conn != null) {
        closeConnection();
    }

}

你能告诉我为什么它在这段代码中工作。 第二个代码

ResultSet rs = null;
    PreparedStatement pstmt = null;

    try {
        pstmt = getPreparedStatement(sql);
        rs = (ResultSet) pstmt.executeQuery();
        while (rs.next()) {
            PreparedStatement pstmt1 = null;
            ResultSet rs1 = null;
            if (onlineTestid != 0) {
                int index = 0;
                String newSql = "query";
                pstmt1 = getPreparedStatement(newSql);
                rs1 = (ResultSet) pstmt1.executeQuery();
                if (rs1.next()) {
                }
            }
            closeAll(pstmt1, rs1);
        }
    } finally {
        closeAll(pstmt, rs);
        closeConnection();
    }

这是closeConnection（）方法

public void closeConnection() throws SQLException {
    if (conn != null) {
        conn.close();
        conn = null;
    }
}

提前致谢。

Answer 1

编辑我最初认为这些陈述是在共享连接的时候，事实上，它们似乎并不存在。我已更新，以反映我的新理解。

您正在使用closeAll()方法关闭连接。

while (rs.next()) {
    PreparedStatement pstmt1 = null;
    ResultSet rs1 = null;
    if (condition) {
    } else {
        if (condition) {
            int index = 0;
            String newSql = "query";
            pstmt1 = getPreparedStatement(newSql);
            rs1 = (ResultSet) pstmt1.executeQuery();
            if (rs1.next()) {
            }
        }
    }
    closeAll(pstmt1, rs1);
}

在while循环的倒数第二行，您致电closeAll(pstmt1, rs1)。在closeAll()方法中，语句closeConnection()关闭（我假设我还没有看到代码）任何打开的连接，包括{{1}使用的连接} ResultSet引用。

Answer 2

您正在关闭连接，之后您正在尝试结果集

while (rs.next()) {
            PreparedStatement pstmt1 = null;
            ResultSet rs1 = null;
            if (condition) {
            } else {
                if (condition) {
                    int index = 0;
                    String newSql = "query";
                    pstmt1 = getPreparedStatement(newSql);
                    rs1 = (ResultSet) pstmt1.executeQuery();
                    if (rs1.next()) {
                    }
                }
            }
            closeAll(pstmt1, rs1);// connnection is closed 
        }

让我们假设您有3条记录。所以rs.next()将返回true并且控制进入循环while (rs.next()) {，现在最后你关闭连接，现在再次控制转到while (rs.next()) {但是因为连接已经关闭所以你将在这一行中得到错误。试着调试你会知道错误

ResultSet关闭后不允许操作 - 使用不同的语句

2 个答案: