Question

我有一个必须阻止用户的功能，并且在其中我检查是否有任何结果，但是，即使我设置为返回，它仍会以某种方式在while循环中返回Results are not available如果没有可用的结果，从功能。处理ResultSet时我做错了吗？这种检查没有结果的方法在所有其他功能中都运行良好，但这里存在问题。

public static boolean block(int id, int blocktime) throws Exception, SQLException {
    DatabaseConnection db = new DatabaseConnection();
    db.establishConnection().prepareStatement("SELECT * FROM accounts WHERE id = ?");
    db.setIntParameter(1, id);
    db.executeQuery();

    if (!db.results().isBeforeFirst()) {
        Notify.accountIdInvalid();
        db.close();
        return false;
    }

    while (db.results().next()) {
        int blocked = db.results().getInt("blocked");
        if (blocked == 1) { db.close(); Notify.accountAlreadyBlocked(); return false; }
        else {
            db.close();
            DatabaseConnection db2 = new DatabaseConnection();
            db2.establishConnection().prepareStatement("UPDATE accounts SET blocked = 1, blocktime = ? WHERE id = ?");
            db2.setIntParameter(1, blocktime);
            db2.setIntParameter(2, id);
            db2.executeUpdate();
            db2.close();
        }
    }

    return true;
}

以下是DatabaseConnection中用于处理语句和结果的一些函数。进程始终是相同的，我建立连接，准备语句并执行查询（或更新），它返回我使用的结果。

/**
 * Executes the query.
 * 
 * @return DatabaseConnection
 * @throws Exception if statement doesn't exists.
 */
public DatabaseConnection executeQuery() throws Exception {
    if (this.stmt == null) {
        throw new Exception("Statement for query executing doesn't exist.");
    }

    this.rs = this.stmt.executeQuery();
    return this;
}

/**
 * Executes the update.
 * 
 * @throws Exception 
 */
public void executeUpdate() throws Exception {
    if (this.stmt == null) {
        throw new Exception("Statement for query updating doesn't exist.");
    }

    this.stmt.executeUpdate();
}

/**
 * Returns the results from executed query.
 * 
 * @return ResultSet
 * @throws Exception if results aren't available.
 */
public ResultSet results() throws Exception {
    if (this.rs == null) {
        throw new Exception("Results are not available.");
    }

    return this.rs;
}

我认为它不相关，但无论如何;我正在使用MySQL数据库。

执行查询（JDBC）后结果不可用

0 个答案: