Question

Rather than having complex SQL queries, tries, catch and finals everywhere in the code I have a method execute(SQL, up to three inputs) however if trying to access the ResultsSet this produces outside of the execute you get the error:

"Operation not allowed after ResultSet closed"

Which is because when you close the PreparedStatement it closes the ResultsSetToo (and there seems to be no way around it).

Is there a way to fix this? The only thing I could think of was converting it to an array which is stored

Many thanks for your time,

Answer 1

I have encountered the same problem in the past. Now i use this method:

public ArrayList<Map<String, String>> getListOfMapsFromSQL(String sql) throws SQLException {
    con = DriverManager.getConnection(url,user,pass);
    stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
    ArrayList<Map<String, String>> list = new ArrayList<Map<String, String>>();

    rs = stmt.executeQuery(sql);
    ResultSetMetaData rsmd = rs.getMetaData();

    while(rs.next()){
        Map<String, String> fieldsMap = new HashMap<String, String>();
        for(int i=1; i<=rsmd.getColumnCount(); i++){
            fieldsMap.put(rsmd.getColumnLabel(i), rs.getObject(i).toString());
        }
        list.add(fieldsMap);
    }

    list.trimToSize();
    stmt.close();
    con.close();
    return list;
}

Instead of returning a ResultSet, it returns a list of Maps(each one representing 1 row). The first String is the column Label, and the second is the column’s value. I hope it helps. 🙂