Spring : previous Line in jdbc template

Question

I have this request :

private List<IWsResponse> getBPartnerDetails(String valueNetwork, String reportLevel2) {
        JdbcTemplate tm = new JdbcTemplate(ds.getDataSource());
        StringBuffer sql =  new StringBuffer("SELECT * FROM XRV_BPARTNERDETAILS where rownum < 10 order by BPartner_ID");
        response = tm.query(sql.toString(),  new BPartnerMapper());
        return response;
    }

in the BPartnerMapper, i want to do the following :

get the previous elements in the ResultSet to compare it with actual line

@Override
    public IWsResponse mapRow(ResultSet rs, int rowNum) throws SQLException {
        rs.previous();
        int prev_Bpartner_ID = rs.getInt("BPARTNER_ID");
        int prev_Location_ID = rs.getInt("BPARTNER_LOCATION_ID");
        int prev_User_ID = rs.getInt("User_ID");
        rs.next();
        int Bpartner_ID = rs.getInt("BPARTNER_ID");
        int Location_ID = rs.getInt("BPARTNER_LOCATION_ID");
        int User_ID = rs.getInt("User_ID");
        // My code
    }

I get the error in rs.previous() :

java.sql.SQLException: Invalid operation for forward only resultset : previous

how can i fix that to get the previous elements of resultSet

You shouldn't be doing `next()` or `previous()` in the first place in a `RowMapper`. You should use a `ResultSetExtractor` and simply iterate over the results (keep the last one and compare with the next one). Instead of going back and forward. You should also not create a `JdbcTemplate` each time you need one, performance wise not very smart to do as it is a heavy object to construct. — M. Deinum, Mar 30 '16 at 10:33
What is your use case, why do you need to do this comparison? — M. Deinum, Mar 30 '16 at 10:33

score 0 · Accepted Answer · answered Mar 30 '16 at 10:06

You can't call prev() or next() on the ResultSet as it pre-initialized for the current row.

From the Spring Documentation of mapRow():

Implementations must implement this method to map each row of data in the ResultSet. This method should not call next() on the ResultSet; it is only supposed to map values of the current row.

What you should be doing instead is:

Get an ArrayList out of your query().
Iterate this list and do the needed comparisons.

Spring : previous Line in jdbc template

1 Answers1