[Error] Operation not allowed after ResultSet closed

java.sql.SQLException: Operation not allowed after ResultSet closed

에러 발생~ !!

하나의 Statement에 대해 하나의 ResultSet이 유효합니다. 

아래 참고~하였습니다.

public static void main(String[] args) throws ClassNotFoundException, SQLException {

    Connection conn = null;
    Statement stmt = null;

    Class.forName("com.mysql.jdbc.Driver");

    conn = (Connection) DriverManager.getConnection(DB_URL, USER, PASS);

    stmt = (Statement) conn.createStatement();
    String sql;
    ResultSet rs = null;
    ResultSet rs2 = null;
    ResultSet rs3 = null;
    java.sql.PreparedStatement ps = null;
    int event_id = 10;
    sql = "SELECT id,text from tweet where event_id = " + event_id;
    rs = stmt.executeQuery(sql);

    String text = "";
    Long id;
    while (rs.next()) {
        id = rs.getLong("id");
        text = rs.getString("text");
        System.out.println("tweet = " + text);
        text = text.replaceAll("http[^\\s]+", "");
        text = text.replaceAll("www[^\\s]+", "");
        System.out.println("tweet after removal of links= " + text);

        StringTokenizer st = new StringTokenizer(text);
        while (st.hasMoreTokens()) {
            String stopword = st.nextToken();
            System.out.println("stopword : " + stopword);

            sql = "SELECT * from stopwords WHERE word =" + '"'+stopword+'"';

            Statement stmt2 = conn.createStatement();
            rs2 = stmt2.executeQuery(sql);
            if (rs2.next()) {
                text = text.replaceAll(stopword, "");
                System.out.println("tweet after removing stopword = " + text);
            }
            sql = "SELECT * from filtertweet where tweet_id = " + id + "";

            Statement stmt3 = conn.createStatement();
            rs3 = stmt3.executeQuery(sql);
            if (!rs3.next()) {
                sql = "INSERT INTO filtertweet VALUES(?,?)";
                ps = conn.prepareStatement(sql);
                ps.setLong(1, id);
                ps.setString(2, text);
                ps.executeUpdate();
            }

        }
    }
    stmt.close();
    conn.close();
}

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